Memory Retrieval

Cerebral activation in the elderly may depend on general cognitive decline as well as actual retrieval performance. Consequently, activation between subjects with and without Mild Cognitive Impairment (MCI), and between remembered and non-remembered words was compared. Twenty-one MCI and 29 healthy control subjects learned 180 nouns. During retrieval, subjects had to discriminate these and 180 distractor words. fMRI identified response-related activation. Most retrieval-related activation was comparable in both groups. However, MCI subjects showed more activation in the prefrontal cortex than controls during processing of hits and correct rejections. Hits showed increased activation than misses in the precuneus and left lateral parieto-occipital cortex; misses showed more activation than correct rejections in the precuneus to cuneus. Verbal retrieval activated a large common network in the elderly independently of MCI. Increased activation in MCI subjects in prefrontal cortex depends on response category. Activation differences between response categories might reflect success (hits) and effort (misses). Increased retrieval-related activation may be used as early marker in subjects at risk of Alzheimer's disease.

Episodic memory encoding and retrieva processes have been linked to different neural networks. However, the common brain regions associated with non-relational memory processing during successful encoding (subsequent memory effect) and successful retrieval (recognition effect) have not yet been investigated. Further, the majority of functional imaging studies have been conducted in young subjects, whereas patients from lesion studies, where most neuropsychological models are still based upon, are usually older. Inferences from younger subjects cannot necessarily be applied to the elderly, an issue becoming particularly relevant with our ageing society. Using an event-related fMRI approach we studied 29 healthy elderly subjects (mean age 67.8, SD 5.4 years) with a non-associative task of intentional word list encoding and retrieval. For each subject, behavioural responses were individually classified into four event types (hits, misses, false alarms, correct rejections). Brain areas activated during successful memory encoding comprised the anterior left hippocampus extending into the surrounding parahippocampal gyrus. Regions associated with successful memory retrieval involved a widespread network of anterior left parahippocampal gyrus, bilateral temporal cortices and bilateral ventral and dorsal prefrontal areas. Regions contributing to both successful encoding and retrieval, evidenced by a conjunction analysis, revealed prominent left lateralized activations of the anterior hippocampus and the inferior parietal lobe. Our results indicate that the anterior left hippocampus plays an important role during successful memory encoding and during successful memory retrieval in a task of simple, non-associative wordlist learning in healthy elderly subjects.

Theoretical models conventionally portray the consolidation of memories as a slow process that unfolds during sleep. According to the classical Complementary Learning Systems theory, the hippocampus (HPC) rapidly changes its connectivity during wakefulness to encode ongoing events and create memory ensembles that are later transferred to the prefrontal cortex (PFC) during sleep. However, recent experimental studies challenge this notion by showing that new information consistent with prior knowledge can be rapidly consolidated in PFC during wakefulness and that PFC lesions disrupt the encoding of congruent events in the HPC. The contributions of the PFC to memory encoding have therefore largely been overlooked. Moreover, most theoretical frameworks assume random and uncorrelated patterns representing memories, disregarding the correlations between our experiences. To address these shortcomings, we developed a HPC-PFC network model that simulates interactions between the HPC and PFC during the encoding of a memory (awake stage), and subsequent consolidation (sleeping stage) to examine the contributions of each region to the consolidation of novel and congruent memories. Our results show that the PFC network uses stored memory "schemas" consolidated during previous experiences to identify inputs that evoke congruent patterns of activity, quickly integrate it into its network, and gate which components are encoded in the HPC. More specifically, the PFC uses GABAergic long-range projections to inhibit HPC neurons representing input components correlated with a previously stored memory "schema," eliciting sparse hippocampal activity during exposure to congruent events, as it has been experimentally observed.

Stress is associated with relapse to drugs after abstinence, but the mechanisms for this association are unclear. One mechanism may be that stress enhances abstinent addicts' recall of memories of drugs as stress relievers. This study assessed the effects of stress on free recall and cued recall of 10 heroin-related and 10 neutral words learned 24 h earlier by 102 abstinent heroin addicts. These participants were randomly assigned to three experiments that also assessed attention and working memory. Experiment 1 used a psychosocial stressor (Trier social stress test (TSST)) before testing for recall of heroin-related words. Experiment 2 added administration of the b-adrenoceptor antagonist propranolol 1 h before the psychosocial stressor. Experiment 3 added administration of either cortisol with propranolol, cortisol alone, or propranolol alone 1 h before word recall to determine whether stress enhancement of heroin-related word recall required noradrenergic-glucocorticoid interactions. We found that free recall of heroin-related words in abstinent addicts was enhanced after stress or cortisol administration when compared with a non-stress condition or placebo, respectively, whereas these interventions had no effect on neutral word recall. b-adrenergic blockade blocked the enhancing effect of stress or cortisol on free recall of heroin-related words. Neither stress nor cortisol affected cued recall, attention, or working memory. The potential of b-adrenergic blockade to reduce or block stress-induced enhancement of drug-related memory retrieval may be relevant to preventing stress-induced relapse in abstinent heroin addicts.

The Exybris Pipeline introduces a modular architecture for optimizing contextual memory retrieval and scoring in AI systems, targeting industrial, military, and strategic applications. Leveraging dynamic memory adaptation, contextual scoring, and optimized retrieval mechanisms, Exybris enhances AI model efficiency while minimizing computational overhead. Certain architectural innovations and implementation details are protected under intellectual property frameworks to safeguard their strategic value and are omitted here to maintain confidentiality. This paper introduces the conceptual framework of the Exybris Pipeline, outlining its theoretical foundations and strategic applications. The initial Proof of Concept (PoC) is currently being developed and will be iteratively refined based on experimental results. Interested parties are encouraged to contact the authors for potential partnerships under confidentiality agreements.
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Autobiographical episodic memory represents a subsystem of declarative long-term memory and largely depends on combining information from multiple sources. The purpose of this study was to assess neural correlates of declarative long-term memory in patients with amnestic mild cognitive impairment (MCI) and controls using fMRI and a task requiring autobiographical and semantic memory retrieval. Comparison of the network supporting episodic autobiographical and semantic memory irrespective of remoteness (recent and remote) revealed significant activations in right parietal cortex and precuneus bilaterally in the patients. Autobiographical episodic versus semantic memory retrieval in the controls led to significant bilateral activations of the parietal-temporal junction, left temporal pole, anterior cingulate, retrosplenial cortex and cerebellum. In contrast, MCI patients activated left supplementary motor area, left premotor and superior temporal cortex. In MCI patients compared to controls a dysfunction of the retrosplenial cortex during memory retrieval was revealed by a lack of differential activation in relation to recency of memories and memory type. Our data suggest that MCI leads to a loss of specificity in the neural network supporting declarative long-term memory.

An unresolved question is how much information can be remembered from visual scenes when they are inspected by saccadic eye movements. Subjects used saccadic eye movements to scan a computer-generated scene, and afterwards, recalled as many objects as they could. Scene memory was quite good: it improved with display duration, it persisted over time long after the display was removed, and it continued to accumulate with additional viewings of the same display The persistance of memory for scenes. Nature 412, 401). The occurrence of saccadic eye movements was important to ensure good recall performance, even though subjects often recalled non-fixated objects. Inter-saccadic intervals increased with display duration, showing an influence of duration on global scanning strategy. The choice of saccadic target was predicted by a Random Selection with Distance Weighting (RSDW) model, in which the target for each saccade is selected at random from all available objects, weighted according to distance from fixation, regardless of which objects had previously been fixated. The results show that the visual memory that was reflected in the recall reports was not utilized for the immediate decision about where to look in the scene. Visual memory can be excellent, but it is not always reflected in oculomotor measures, perhaps because the cost of rapid on-line memory retrieval is too great.

This study was aimed at determining the type of the glucocorticoid membrane receptors (mineralocorticoid receptors (MRs) or glucocorticoid receptors (GRs)) in the dorsal hippocampus (dHPC) involved in the rapid effects of corticosterone or stress on memory retrieval. For that purpose, we synthesized corticosterone-3-O-carboxymethyloxime-bovine serum albumin conjugate (Cort-3CMO-BSA) conjugate (a high MW complex that cannot cross the cell membrane) totally devoid of free corticosterone, stable in physiological conditions. In a first experiment, we evidenced that an acute stress (electric footshocks) induced both a dHPC corticosterone rise measured by microdialysis and memory retrieval impairment on delayed alternation task. Both the endocrinal and cognitive effects of stress were blocked by metyrapone (a corticosterone synthesis inhibitor). In a second experiment, we showed that bilateral injections of either corticosterone or Cort-3CMO-BSA in dHPC 15 min before memory testing produced impairments similar to those resulting from acute stress. Furthermore, we showed that anisomycin (a protein synthesis inhibitor) failed to block the deleterious effect of Cort-3CMO-BSA on memory. In a third experiment, we evidenced that intra-hippocampal injection of RU-28318 (MR antagonist) but not of RU-38486 (GR antagonist) totally blocked the Cort-3CMO-BSA-induced memory retrieval deficit. In a fourth experiment, we demonstrated that RU-28318 administered 15 min before stress blocked the stress-induced memory impairments when behavioral testing occurred 15 min but not 60 min after stress. Overall, this study provides strong in vivo evidence that the dHPC membrane GRs, mediating the rapid and non-genomic effects of acute stress on memory retrieval, are of MR but not GR type.

Human mental representations are both flexible and structured—properties that, together, present challenging design requirements for a model of human thinking. The Learning and Inference with Schemas and Analogies (LISA) model of analogical reasoning aims to achieve these properties within a neural network. The model represents both relations and objects as patterns of activation distributed over semantic units, integrating these representations into propositional structures using synchrony of firing. The resulting propositional structures serve as a natural basis for memory retrieval, analogical mapping, analogical inference, and schema induction. The model also provides an a priori account of the limitations of human working memory and can simulate the effects of various kinds of brain damage on thinking.

Enhanced physical activity is associated with improvements in cognitive function in rodents as well as in humans. The authors examined in detail which aspects of learning and memory are influenced by exercise, using a spatial Y-maze test combined with a 14-day exercise paradigm at different stages of learning. The authors show that 14 days of wheel running promotes memory acquisition, memory retention, and reversal learning. The exercise paradigm that was employed also significantly increased the number of maturing neurons, suggesting that an increase in neurogenesis underlies the positive effects of exercise on Y-maze performance. Finally, the authors show that memory acquisition in itself does not have a major impact on the number of immature neurons. However, memory retention testing and reversal learning both cause a significant reduction in the number of doublecortin and Ser133phosphorylated pCREB-positive cells, indicating that a decrease in neurogenesis might be a prerequisite for optimal memory retrieval.

This research extends the dual coding theory of memory retrieval (Paivio 1969, 2007) beyond its traditional focus on verbal and pictorial information to olfactory information. We manipulate the presence or absence of olfactory and pictorial stimuli at the time of encoding (study 1) or retrieval (study 2) and measure the impact on verbal recall. After a time delay, scent enhances recall of verbal information, and scent‐based retrieval cues potentiate the facilitative effect of pictures on recall. These results cannot be attributed merely to increased elaboration at the time of exposure.

In typical interactions, speakers frequently produce utterances that appear to reflect beliefs about the common ground shared with particular addressees. Horton and Gerrig (2005a) proposed that one important basis for audience design is the manner in which conversational partners serve as cues for the automatic retrieval of associated information from memory. This paper reports the results of two experiments demonstrating the influence of partner-specific memory associations on language production. Following an initial task designed to establish associations between specific words (Experiment 1) or object categories (Experiment 2) and each of two partners, participants named a series of pictures in the context of the same two individuals. Naming latencies were shortest for responses associated with the current partner, and were not significantly correlated with explicit recall of partner-item associations. Such partner-driven memory retrieval may constrain the information accessible to speakers as they produce utterances for particular addressees. During conversational interactions, the form and content of speakers' utterances are potentially shaped in a variety of ways by the intended audience. Speakers not only adjust global characteristics of their speech, such as overall complexity, in response to the perceived needs of particular types of addressees (e.g., non-native speakers; Bortfeld & Brennan, 1997), but can also make relatively fine-grained adjustments to referential (e.g., , syntactic (e.g., Haywood, Pickering, & Branigan, 2005) and even gestural (e.g., Özyürek, 2002) aspects of their behaviors based on interactions with specific individuals. Taken together, these partner-related adjustments are known as audience design and appear to be a ubiquitous feature of conversational speech. Although utterances routinely show evidence of having been tailored for certain addressees, the cognitive mechanisms that underlie audience design are not well understood. A primary issue concerns the extent to which instances of audience design necessarily emerge on the basis of considerations of the knowledge taken as shared between interlocutors-their common ground. Although individuals are presumed to coordinate interactions on the basis of beliefs about common ground , evidence is mixed regarding when and how this actually occurs (for a discussion, see . For example, speakers sometimes fail to consider addressees as much as they "should," producing utterances that are ambiguous or that show little evidence of addressee-specific adjustments . Conversely, some aspects of utterances that could be potentially helpful for addresses-e.g., articulatory reduction or heavy NP shift -may emerge instead on the basis of speaker-internal constraints.

In the honeybee Apis mellifera, multiple-trial olfactory conditioning of the proboscis extension response speciWcally leads to long-term memory (LTM) which can be retrieved more than 24 h after learning. We studied the involvement of nicotinic acetylcholine receptors in the establishment of LTM by injecting the nicotinic antagonists mecamylamine (1 mM),-bungarotoxin (-BGT, 0.1 mM) or methyllycaconitine (MLA, 0.1 mM) into the brain through the median ocellus 20 min before or 20 min after multiple-trial learning. The retention tests were performed 1, 3, and 24 h after learning. Pre-training injections of mecamylamine induced a lower performance during conditioning but had no eVect on LTM formation. Post-training injections of mecamylamine did not aVect honeybees' performances. Pre-training injections of MLA or post-training injection of-BGT speciWcally induced LTM impairment whereas acquisition as well as memory retrieval tested 1 or 3 h after learning was normal. This indicates that brain injections of-BGT and MLA did not interfere with learning or medium-term memory. Rather, these blockers aVect the LTM. To explain these results, we advance the hypothesis that honeybee-BGT-sensitive acetylcholine receptors are also sensitive to MLA. These receptors could be essential for triggering intracellular mechanisms involved in LTM. By contrast, medium-term memory is not dependent upon these receptors but is aVected by mecamylamine.

Can participants retrieve information about the 2nd of 2 stimuli while they are processing the 1st? Four experiments suggest they can. Reaction times to the 1st stimulus were faster if it came from the same category as the 2nd than if it came from a different category. This category-match effect was observed for letter-digit discrimination (Experiment 1), magnitude and parity judgments about digits (Experiment 2), and lexical decisions (Experiment 3). Experiment 4 showed that the 2nd stimulus could semantically prime the 1st. The category-match effect was observed only when the same task was performed on the 2 stimuli. When the task changed from the 1st stimulus to the 2nd, there was no advantage of a category match. This dependence on task set may explain previous failures to find parallel retrieval. This article is concerned with the possibility of parallel memory retrieval in dual-task situations. Can people retrieve information about one stimulus while they are busy processing another? This question has been important in the memory literature for decades, and many studies have addressed it throughout that period (see below). Many of the studies had procedural limitations that undermined their ability to address the question of parallel retrieval precisely. Two recent studies overcame these limitations by using the psychological refractory period (PRP) procedure, but they suggested opposite conclusions: Carrier and Pashler (1995) argued that memory retrieval was strictly serial, whereas Hommel's (1998) results suggest that memory retrieval may be parallel. Our research addressed procedural, analytic, and logical differences between the studies and found evidence supporting parallel retrieval that has implications for theories of the PRP as well as theories of memory. We should make clear that we are addressing parallel retrieval between tasks rather than within tasks. Most formal theories of memory assume parallel retrieval within tasks, in that a single memory probe accesses all traces in memory concurrently (e.g.,

We report that, in the rat, administering insulin-like growth factor II (IGF-II) significantly enhances memory retention and prevents forgetting. Inhibitory avoidance learning leads to an increase in hippocampal expression of IGF-II, which requires the transcription factor CCAAT enhancer binding protein β and is essential for memory consolidation. Furthermore, injections of recombinant IGF-II into the hippocampus after either training or memory retrieval significantly enhance memory retention and prevent forgetting. To be effective, IGF-II needs to be administered within a sensitive period of memory consolidation. IGF-II-dependent memory enhancement requires IGF-II receptors, new protein synthesis, the function of activity-regulated cytoskeletal-associated protein and glycogensynthase kinase 3 (GSK3). Moreover, it correlates with a significant activation of synaptic GSK3β and expression of GluR1 a-amino-3-hydroxy-5methyl-4-isoxasoleproprionic acid receptor subunits. In hippocampal slices, IGF-II promotes IGF-II receptor-dependent, persistent long-term potentiation after weak synaptic stimulation. Thus, IGF-II may represent a novel target for cognitive enhancement therapies. Elucidating the mechanisms of memory enhancement is critical for the development of cognitive enhancement therapies. Memory strengthening and persistence depend on consolidation, a process whereby newly learned information, which is initially labile, becomes stronger and resilient to disruption 1. This process recruits evolutionarily conserved de novo RNA and protein syntheses, the function of members of the cAMP response Users may view, print, copy, download and text and data-mine the content in such documents, for the purposes of academic research, subject always to the full Conditions of use: http://www.nature.com/authors/editorial_policies/license.html#terms Correspondences and requests for materials should be sent to C.M.A.

Often, retrieval cues are not uniquely related to one specific memory, which could lead to memory interference. Controlling interference is particularly important during episodic memory retrieval or when remembering specific events in a spatiotemporal context. Despite a clear involvement of prefrontal cortex (PFC) in episodic memory in human studies, information regarding the mechanisms and neurotransmitter systems in PFC involved in memory is scarce. Although the serotoninergic system has been linked to PFC functionality and modulation, its role in memory processing is poorly understood. We hypothesized that the serotoninergic system in PFC, in particular the 5-HT2A receptor (5-HT2AR) could have a role in the control of memory retrieval. In this work we used different versions of the object recognition task in rats to study the role of the serotoninergic modulation in the medial PFC (mPFC) in memory retrieval. We found that blockade of 5-HT2AR in mPFC affects retrieval of an object...

The neocortex is thought to be a distributed learning system that gradually integrates semantic information into the initial mnemonic representation rapidly formed by the hippocampus after acquisition. Nevertheless, an emerging view suggests that some cortical regions, in particular the medial prefrontal cortex (mPFC), may also have a role during the initial steps of memory consolidation as well as in the recall of recent memories. Here, we show that mPFC plays a critical role during the first few hours of inhibitory avoidance memory consolidation and is necessary for the normal retrieval of both recent and remote memories, supporting the idea that involvement of neocortical areas in memory processing is not restricted to the late post-training consolidation phase.

Pre-test exposure to training-related cues is known to improve subsequent retention performance. To identify brain regions engaged in processes promoted by retrieval cues, a brain imaging approach using the [6-14 C]glucose autoradiographic technique was used. Sprague-Dawley rats trained in a brightness discrimination avoidance task were submitted to different cueing conditions after a 1-or a 21-day training-to-test interval (TTI). Animals were either non-cued, cued with a box, or cued with a box and the light that served as a discriminative stimulus. Effects of the different cueing conditions on retention performance or on metabolic activity in 58 different brain regions were investigated. Rats cued with the light exhibited a subsequent improvement of their retention performance relative to controls, when tested at the 1-but not 21-days TTI, confirming our previous results. At the 1-day retention interval, a comparison between rats cued with the box and rats cued with the box and the light showed that the light cue significantly increased glucose uptake in a neuronal network composed of the lateral, basal, and central nuclei of the amygdala, the anterior and suprachiasmatic hypothalamic nuclei, the nucleus accumbens, the medial septum, and the insular cortex. In contrast, at the 21-day retention interval, both groups demonstrated similar cerebral metabolic activity. The present results indicate that exposure to a light cue increased metabolic activity in the previously mentioned brain structures only when the light acted as an effective retrieval cue, suggesting an involvement of this network in the processes triggered by a retrieval cue. Arguments are provided supporting the notion that the amygdala may play a key role in these processes. Whether the amygdala is a part of a neural network involved in retrieval processes or in neuromodulating systems that favour the efficacy of retrieval processes is also discussed.

The involvement of MAPK pathways in retrieval was investigated in a situation where reactivation of memory was dissociated from its behavioural expression. In rats trained in a brightness avoidance discrimination task, exposure to the discriminative stimulus had behavioural and molecular consequences: a facilitation of the retention performance and a decrease in ERK phosphorylation in the prefrontal cortex and amygdala, but not in the hippocampus. These results indicate that reactivation processes engage a down-regulation of ERK, possibly related to increases in glucocorticoids, in the amygdala and prefrontal cortex already known to be involved in emotional retrieval.

In most studies on animal learning, individual animals are tested separately in a specific learning environment and with a limited number of trials per day. An alternative approach is to test animals in a familiar environment in their social group. In this study, the authors-applying a fully automated learning device-investigated voluntary, self-controlled visual shape discrimination learning of group-housed dwarf goats (Capra hircus). The majority of the tested goats showed successful shape discrimination, which indicates the adaptive value of an effective learning strategy. However, in each group, a few individual goats developed behavioral strategies different from shape discrimination to get reward. Relocation impairs memory retrieval (probably by attention shifting) only temporarily for previously learnt shapes. The results demonstrate the usefulness of a self-controlled learning paradigm to assess learning abilities of social species in their normal social settings. This may be especially relevant for captive animals to improve their welfare.

Background and Objective: Alzheimer is the most common form of dementia in elderly persons. Oxidative stress is one of the main pathological factors in Alzheimer’s disease. This study was done to investigate the effect of crosin on histological changes of hippocampus and memory impairment which induced by scopolamine in the male rats. Methods: In this experimental study, 30 male rats were randomly allocated into 3 groups including: control, scopolamine and scopolamine with crosin treated groups. Scopolamine with dose of 3 mg/kg/bw for one week and crocin with dose of 30mg/kg for two weeks were administered, intraperitoneally. The learning and spatial memory parameters were evaluated by Morris water maze test. Then the animals were sacrificed and their hippocampi were removed immediately for histological evaluation. Results: Scopolamine injection causes significantly increased the number of dark cells in CA1 region of hippocampus in compared to control group (P<0.05). Treatment wi...

This paper outlines an inclusion initiative's conceptual framework for programs serving secondary students from economically challenged communities. It proposes distance learning technologies to afford these students access to learning resources, experiences, and environments in STEM. This paper addresses concerns with a complex duality of environmental factors: the environments in which these students are reared and currently reside; and the alteration to the environments in which they "traditionally" learning. It outlines a process where components participating in online learning experiences contribute to developing motivational and learning strategies to overcome environmental conditions and achieve academic excellence.

The sensitivity of event-related fields (ERFs) to memory retrieval processes is not well determined. This stands in sharp contrast to event-related potential (ERP) studies, as ERPs have been employed widely to address questions about the functional architecture supporting memory retrieval. Despite their success in this endeavour, however, the sensitivity of ERPs to one retrieval process-familiarity-is somewhat limited. This experiment was designed to determine the sensitivity of ERFs to familiarity, and thus to examine the functional leverage that is available to investigate item familiarity via magnetic means of indexing retrieval processing in real-time. The analyses of the ERF data focused on old/new effects, which are differences between the neural activities associated with old (previously studied) and new test items that attract correct memory judgments. The ERFs showed a level of sensitivity to changes in item familiarity superior to that reported previously in very similar studies where ERPs were acquired. Moreover, analyses of the ERF data revealed four functionally distinct old/new effects. These findings provide strong incentives for employing ERFs in subsequent studies of human memory retrieval processing operations.

In the present study, the possible role of nicotinic acetylcholine (nACh) receptors of the ventral tegmental area (VTA) on morphine-state-dependent learning was studied in adult male Wistar rats. As a model of memory, a step-through type passive avoidance task was used. All animals were bilaterally implanted with chronic cannulae in the VTA, trained using a 1mA foot shock, and tested 24h after training to measure step-through latency. Post-training subcutaneous (s.c.) injection of morphine (0.5-5mg/kg) dose-dependently reduced the step-through latency, showing morphine-induced amnesia. Amnesia induced by post-training morphine was significantly reversed by pre-test administration of morphine (2.5-5mg/kg, s.c.) and induced morphine-state-dependent learning. Pre-test injection of nicotine (0.25-1microg/rat) into the VTA plus an ineffective dose of morphine (0.5mg/kg) significantly restored the memory retrieval. It should be noted that pre-test intra-VTA injection of the same doses of ...

Background: Posterior cortical atrophy (PCA) may represent a discrete syndrome of Alzheimer’s disease (AD) rather than amnestic AD with visual deficits. Methods: We separated 30 patients with PCA based on ventral and dorsal visual symptoms using cluster analysis and analyzed the demographic, cognitive, and functional imaging features. Results: This analysis revealed subgroups of 26 dorsal and 4 ventral patients. The ventral subgroup had greater confrontational naming impairment, and the dorsal subgroup had greater hypofunction in the parietal regions. The PCA cohort had memory retrieval rather than encoding deficits, and clinical follow-up showed relative isolation of dorsal and ventral visual manifestations. Conclusion: These results support 2, mostly nonoverlapping syndromes in patients with PCA, with the commonest affecting the dorsal visual pathway; moreover, the memory retrieval difficulty in the patients with PCA was dissimilar to the amnestic pattern in typical AD. These resu...

One-trial conditioning of the proboscis extension reflex (PER) in honeybees was used to examine the qualitative effects of two muscarinic antagonists, atropine and pirenzepine, on the acquisition and retrieval of memory following intracranial injection. The main result of this study is that atropine, at a relatively high concentration of 10 Ϫ 2 M, impairs memory retrieval but not acquisition of memory after a single olfactory conditioning trial (at this concentration, there is no effect of atropine on the sensorimotor components of the PER). This result is in agreement with the effects of scopolamine, reported in a previously published article. Pirenzepine, at the same concentration as atropine, had no effect on either acquisition or retrieval of memory. These results suggest that blockade of muscarinic-like receptors, except those that bind to pirenzepine, induces solely an impairment of memory retrieval.

Previous in vivo electrophysiological studies suggest that the anterior cingulate cortex (ACgx) is an important substrate of novel object recognition (NOR) memory. However, intervention studies are needed to confirm this conclusion and permanent lesion studies cannot distinguish effects on encoding and retrieval. The interval between encoding and retrieval tests may also be a critical determinant of the role of the ACgx. The current series of experiments used micro-infusion of the GABA A receptor agonist, muscimol, into ACgx to reversibly inactivate the area and distinguish its role in encoding and retrieval. ACgx infusions of muscimol, before encoding did not alter NOR assessed after a delay of 20 min or 24 h. However, when infused into the ACgx before retrieval muscimol impaired NOR assessed after a delay of 24 h, but not after a 20-min retention test. Together these findings suggest that the ACgx plays a time-dependent role in the retrieval, but not the encoding, of NOR memory, neuronal activation being required for the retrieval of remote (24 h old), but not recent (20 min old) visual memory.

Previous in vivo electrophysiological studies suggest that the anterior cingulate cortex (ACgx) is an important substrate of novel object recognition (NOR) memory. However, intervention studies are needed to confirm this conclusion and permanent lesion studies cannot distinguish effects on encoding and retrieval. The interval between encoding and retrieval tests may also be a critical determinant of the role of the ACgx. The current series of experiments used micro-infusion of the GABAA receptor agonist, muscimol, into ACgx to reversibly inactivate the area and distinguish its role in encoding and retrieval. ACgx infusions of muscimol, before encoding did not alter NOR assessed after a delay of 20 min or 24 h. However, when infused into the ACgx before retrieval muscimol impaired NOR assessed after a delay of 24 h, but not after a 20-min retention test. Together these findings suggest that the ACgx plays a time-dependent role in the retrieval, but not the encoding, of NOR memory, ne...

Honeybees (Apis mellifera) exhibit an extraordinarily tuned division of labor that depends on age polyethism. This adjustment is generally associated with the fact that individuals of different ages display different response thresholds to given stimuli, which determine specific behaviors. For instance, the sucrose-response threshold (SRT) which largely depends on genetic factors may also be affected by the nectar sugar content. However, it remains unknown whether SRTs in workers of different ages and tasks can differ depending on gustatory and olfactory experiences. Groups of worker bees reared either in an artificial environment or else in a queen-right colony, were exposed to different reward conditions at different adult ages. Gustatory response scores (GRSs) and odor-memory retrieval were measured in bees that were previously exposed to changes in food characteristics. Results show that the gustatory responses of pre-foraging-aged bees are affected by changes in sucrose solutio...

Research into reading performance during the 1980s suggested that reading from video display terminals (VDTs) was slower and less accurate than reading from printed material. A recent study by Mayes et al. (Int. J. Ind. Ergon. 28 (2001) 367) reported in this journal also indicated that reading from a VDT took significantly longer than reading from paper. In reply to this, we report a study that examined directly comparable text in the two media in terms of study and reading times, number of correct answers and a memory retrieval measure. Neither study or reading times, nor the level of correct answers differed between the two forms of presentation, but the manner in which learned information was recalled did show a significant difference. It is suggested our replicated findings indicate that when material is adequately matched across media, reading times and number of correct answers do not differ, but differences in cognitive processing associated with memory assimilation do occur. This has major implications for the use of VDT presentation of knowledge. Further, the findings suggest that more traditional forms of performance measures, in particular reading speed, may be poor indicators of the amount and quality of information obtained from reading from VDTs in comparison to hard copy. Relevance to industry In the 1980s, research indicated reading performance was less for computers than paper. It is suggested this is not the case today, although the two media do have different effects on cognitive processing as measured by memory processes. This has important implications for using computers in learning and training activities.

The hippocampus, a region implicated in the processing of spatial information and episodic memory, is central to the debate concerning the relationship between episodic and semantic memory. Studies of medial temporal lobe amnesic patients provide evidence that the hippocampus is critical for the retrieval of episodic but not semantic memory. On the other hand, recent neuroimaging studies of intact individuals report hippocampal activation during retrieval of both autobiographical memories and semantic information that includes historical facts, famous faces, and categorical information, suggesting that episodic and semantic memory may engage the hippocampus during memory retrieval in similar ways. Few studies have matched episodic and semantic tasks for the degree to which they include spatial content, even though spatial content may be what drives hippocampal activation during semantic retrieval. To examine this issue, we conducted a functional magnetic resonance imaging (fMRI) study in which retrieval of spatial and nonspatial information was compared during an episodic and semantic recognition task. Results show that the hippocampus (1) participates preferentially in the retrieval of episodic memories; (2) is also engaged by retrieval of semantic memories, particularly those that include spatial information. These data suggest that sharp dissociations between episodic and semantic memory may be overly simplistic and that the hippocampus plays a role in the retrieval of spatial content whether drawn from a memory of one's own life experiences or real-world semantic knowledge.

The effect of physical activity (PA) on functional brain activation for semantic memory in amnestic mild cognitive impairment (aMCI) was examined using event-related fMRI during fame discrimination. Greater semantic memory activation occurred in the left caudate of High-versus Low-PA patients (P = 0.03), suggesting PA may enhance memory-related caudate activation in aMCI.

a These authors contributed equally to this study AUTHOR CONTRIBUTIONS J.M.B. performed the molecular biology and biochemistry experiments and analyzed the data. D.B.D. carried out the spinal cord slice release and formalin behavior experiments. S.M.W. performed immunocytochemistry and wrote the manuscript. C.B. carried out the laser Doppler blood flowmetry. W.Z. performed DRG patching. Y.W. conducted whole cell electrophysiology on hippocampal neurons. W.S. and X.J. performed electrophysiology on slices. B.S.S. carried out the DRG release assays. T.B. and N.B. performed and analyzed the calcium imaging experiments. M.K. and S.OM. performed the SPR experiments. N.L. performed the rotarod and water maze experiments. J.C.F. performed the nocifensive behavior experiments and helped write the manuscript. N.M.A. and A.H. synthesized the peptide blot. C.M.H. and M.R.V. contributed to editing of the manuscript. J.H.H. analyzed the blood flow data and edited the writing of the manuscript. F.A.W. analyzed the ddC behavior data and contributed to editing the manuscript. R.K. conceived the study, designed and supervised the overall project and wrote the manuscript.

This article provides an overview of the relationships among working memory, math performance, and math anxiety. We provide examples from the mathematical cognition literature to show: the critical role of working memory in performing arithmetic and math; the relationship between math performance and math anxiety, especially on standardized math achievement tests; and finally, the way that math anxiety compromises the functioning of working memory when people do arithmetic and math. We conclude with some predictions concerning the risk factors for math anxiety, and with some of the educational implications of this work. See Ashcraft and Ridley (2005) and Ashcraft, Krause, and Hopko (2007) for full-length treatments of these issues. Excellent summaries of the entire field of mathematical cognition can be found in Campbell (2005). We begin with a statement concerning just one justification (of many) for this work. Math and science are in the headlines these days, with research-based reports about the relatively poor job American schools do in teaching math and science, and the depressingly substandard job many students are doing in mastering these topics. No one doubts the importance of math and science to the workforce in a technological society, or their importance in general to an educated populace. So there is a general, undeniable need for investigations about the learning and mastery of math. And from a disciplinary perspective, the rich complexity of math in all its facets suggests that it should be an interesting topic for cognitive psychology to address, and a critical one in any discussion of the relevance of cognitive psychology to education. Working Memory and Math Performance Considerable evidence has appeared in the past 10 to 15 years concerning the vital role that working memory plays in mathematical cognition. In LeFevre, DeStefano, Coleman, and Shanahan's (2005) view, the literature now supports a clear generalization concerning the important positive relationship between the complexity of arithmetic or math problems and the demand on working memory for problem solving. One aspect of this relationship involves the numerical values being manipulated, and one aspect examines the total number of steps required for problem solution. We take these in turn. It is now clear that working memory is increasingly involved in problem solving as the numbers in an arithmetic or math problem (the "operands") grow larger. The benchmark effect in this area is the problem-size effect, the empirical result that response latencies and errors increase as the size of the operands increases: For example, 6 7 or 9 6 will be answered more slowly and less accurately than 2 3 or 4 5 (see Zbrodoff & Logan's 2005 review). Part of this effect, we have argued, is due to the structure of the mental representation of arithmetic facts in long-term memory, and the inverse relationship between problem size and problem frequency-for example, in textbooks (e.g., Hamann & Ashcraft, 1986). That is, larger arithmetic problems simply occur less frequently, and hence are stored in memory at lower levels of strength (see Siegler & Shrager, 1984, for a comparable approach); this is similar in most respects to the standard word-frequency effect found in language processing research. A second part of the effect, documented in the 243

As family therapy of sexual abuse survivors has become more common, theoretical and technical issues have received considerable attention. Less attention has been devoted to the countertransference experience of the therapist. Unexamined therapist countertransference is a critical element in the treatment of these families, which markedly influences the nature and direction of treatment. Particular types ofcountertransference are presented here. In addition, the contention is made that counte~ransference is not only evoked by the particular presentation of the family members, but also by the therapist's unexplored political and moral beliefs.

Resolving links between subsequent referents (e.g., the car) and open discourse roles (as in Keith drove to London yesterday. The car kept overheating) is crucial for discourse understanding. This article investigates the contribution of lexical semantic factors (e.g., that drive implies using a vehicle) as compared to more general contextual factors in the on-line resolution of such links. We report an eye-tracking experiment that measures immediate and delayed effects of both kinds of information as readers resolve the reference. The results indicate that lexical information dominates the initial linking process with more general contextual influences emerging later. They are discussed in terms of the distinction between early bonding and subsequent resolution processes that has been proposed for other kinds of anaphoric interpretation (Sanford, Garrod, Lucas, & Henderson, 1983).

The use of the computer as a model, metaphor, and modelling tool has tended to privilege the 'cognitive' over the 'affective' by engendering theories in which thinking and learning are viewed as information processing and affect is ignored or marginalised. In the last decade there has been an accelerated flow of findings in multiple disciplines supporting a view of affect as complexly intertwined with cognition in guiding rational behaviour, memory retrieval, decision-making, creativity, and more. It is time to redress the imbalance by developing theories and technologies in which affect and cognition are appropriately integrated with one another. This paper describes work in that direction at the MIT Media Lab and projects a large perspective of new research in which computer technology is used to redress the imbalance that was caused (or, at least, accentuated) by the computer itself.

This paper investigates the potential involvement of semantics in the processing of agreement. Forty Italian speakers participated to a self-paced reading test. We examined the reaction times and acceptability ratings with respect to Italian quantification expressions such as ‘a bag of / a bunch of’+ concrete/abstract noun. These expressions show two possibilities concerning Number agreement: the verb can agree either with the quantifier (syntactic agreement) or with the noun that it modifies (semantic agreement). When containing a concrete noun (e.g. bunch of lemons), these expressions are ambiguous between a reading in which the NP ‘bag’ is modified by a second NP denoting its content (i.e. a bag full of lemons) and a reading in which ‘bag’ quantifies over the NP head (i.e. lemons). The ambiguity disappears when the NP contains an abstract noun (e.g. a bunch of concepts). Results showed a preference for agreement with the concrete noun. We will discuss these findings arguing that ...

Honeybees (Apis mellifera) exhibit an extraordinarily tuned division of labor that depends on age polyethism. This adjustment is generally associated with the fact that individuals of different ages display different response thresholds to given stimuli, which determine specific behaviors. For instance, the sucrose-response threshold (SRT) which largely depends on genetic factors may also be affected by the nectar sugar content. However, it remains unknown whether SRTs in workers of different ages and tasks can differ depending on gustatory and olfactory experiences. Groups of worker bees reared either in an artificial environment or else in a queen-right colony, were exposed to different reward conditions at different adult ages. Gustatory response scores (GRSs) and odor-memory retrieval were measured in bees that were previously exposed to changes in food characteristics. Results show that the gustatory responses of pre-foraging-aged bees are affected by changes in sucrose solutio...

Chronometric studies of language and memory processing typically emphasize changes in mean response time (RT) performance across conditions. However, changes in mean performance (or the lack thereof) may reflect distinct patterns at the level of underlying RT distributions. In seven experiments, RT distributional analyses were used to better understand how distributions change across related and unrelated conditions in standard semantic priming paradigms. In contrast to most other lexical variables, semantic priming in standard conditions simply shifts the RT distribution, implicating a headstart mechanism. However, when targets are degraded, the priming effect increases across the RT distribution, a pattern more consistent with current computational models of semantic priming. Interestingly, priming effects also increase across the RT distribution when targets are degraded and primes are highly masked, supporting a memory retrieval account of priming under degraded conditions. Finally, strengths and limitations of alternative approaches for modeling RT distributions are discussed.

In the present research, we provide empirical evidence for the process of symbolic integration of number associations, focusing on the development of simple addition (e.g., 5 + 3 = 8), subtraction (e.g., 5-3 = 2), and multiplication (e.g., 5 x 3 = 15). Canadian children were assessed twice, in grade 2 and grade 3 (N = 244; 55% girls). All families were English-speaking, and parent education levels ranged from high school to postgraduate, with a median of community college. In grade 2, children completed general cognitive tasks (i.e., receptive vocabulary, working memory, nonverbal reasoning, and inhibitory control). In both grades, children completed single-digit addition and complementary subtraction problems. In grade 3, they completed single-digit multiplication problems and measures of applied mathematics, specifically, word-problem solving, algebra, and measurement. We found that addition and subtraction were reciprocally related (controlling for cognitive skills). Subtraction fluency predicted multiplication in grade 3, whereas addition fluency did not. In grade 3, both subtraction and multiplication fluency were predictors of applied mathematics, with multiplication partially mediating the relation between subtraction and applied mathematics performance. These findings support the view that learning arithmetic associations is a hierarchical process. As students practice each new skill, individual differences reflect the integration of the novel component into the developing associative network.

Attractor neural networks are thought to underlie working memory functions in the cerebral cortex. Several such models have been proposed that successfully reproduce firing properties of neurons recorded from monkeys performing working memory tasks. However, the regular temporal structure of spike trains in these models is often incompatible with experimental data. Here, we show that the in vivo observations of bistable activity with irregular firing at the single cell level can be achieved in a large-scale network model with a modular structure in terms of several connected hypercolumns. Despite high irregularity of individual spike trains, the model shows population oscillations in the beta and gamma band in ground and active states, respectively. Irregular firing typically emerges in a high-conductance regime of balanced excitation and inhibition. Population oscillations can produce such a regime, but in previous models only a non-coding ground state was oscillatory. Due to the modular structure of our network, the oscillatory and irregular firing was maintained also in the active state without fine-tuning. Our model provides a novel mechanistic view of how irregular firing emerges in cortical populations as they go from beta to gamma oscillations during memory retrieval.

Fourteen subjects were scanned in two fMRI sessions separated by several months. During each session, subjects performed an episodic retrieval task, a semantic retrieval task, and a working memory task. We found that 1) despite extensive intersubject variability in the pattern of activity across the whole brain, individual activity patterns were stable over time, 2) activity patterns of the same individual performing different tasks were more similar than activity patterns of different individuals performing the same task, and 3) that individual differences in decision criterion on a recognition test predicted the degree of similarity between any two individuals' patterns of brain activity, but individual differences in memory accuracy or similarity in structural anatomy did not. These results imply that the exclusive use of group maps may be ineffective in profiling the pattern of activations for a given task. This may be particularly true for a task like episodic retrieval, which is relatively strategic and can involve widely-distributed specialized processes that are peripheral to the actual retrieval of stored information. Further, these processes may be differentially engaged depending on individual differences in cognitive processing and/or physiology.

The present fMRI study investigates, first, whether learning new arithmetic operations is reflected by changing cerebral activation patterns, and second, whether different learning methods lead to differential modifications of brain activation. In a controlled design, subjects were trained over a week on two new complex arithmetic operations, one operation trained by the application of backup strategies, i.e., a sequence of arithmetic operations, the other by drill, i.e., by learning the association between the operands and the result. In the following fMRI session, new untrained items, items trained by strategy and items trained by drill, were assessed using an eventrelated design. Untrained items as compared to trained showed large bilateral parietal activations, with the focus of activation along the right intraparietal sulcus. Further foci of activation were found in both inferior frontal gyri. The reverse contrast, trained vs. untrained, showed a more focused activation pattern with activation in both angular gyri. As suggested by the specific activation patterns, newly acquired expertise was implemented in previously existing networks of arithmetic processing and memory. Comparisons between drill and strategy conditions suggest that successful retrieval was associated with different brain activation patterns reflecting the underlying learning methods. While the drill condition more strongly activated medial parietal regions extending to the left angular gyrus, the strategy condition was associated to the activation of the precuneus which may be accounted for by visual imagery in memory retrieval.

The present study aimed at investigating age-related changes and mild cognitive impairment (MCI) related effects in simple arithmetic. To pursue this goal, MCI patients, healthy old adults and young adults performed three computerised tasks. The production (e.g., 3 × 4 = ?) and the verification task (3 × 4 12?) evaluated direct access to multiplication knowledge, the number-matching task (3 × 4 34?, 'do 3 × 4 and 34 have the same digits?') tested indirect access. In verification and number-matching, interference from related distractors (e.g., 3 × 4 followed by 16) relative to unrelated distractors (17) reflects access to stored fact representations as well as efficiency of inhibition processes. Results indicated that, compared to young adults, MCI and healthy old adults were slower in responding across tasks. In production and verification, analyses of individual latency regression slopes and intercepts suggested that these age effects were related to differences at peripheral processing stages (e.g., encoding) rather than at the central (arithmetic retrieval) stage. Differences between MCI and healthy elderly emerged only in the number-matching task. While in verification effects were comparable between groups, in number-matching MCI patients were more susceptible to interference from irrelevant information than healthy old participants. Overall, the present findings indicate that aging has a general effect on peripheral processing speed, but not on arithmetic memory retrieval.