Psychology

We studied the effect of different postoperative times on the behavioral recovery following brain implants. Adult male rats received cortical tissue grafts 2 weeks after aspiration of the medial frontal cortex. Either 2 (Immediate Group) or 28 (Delay Group) days after grafting, the performance of these rats on a behavioral battery, comprising the Morris water maze task, forepaw use, and grooming, was compared to that of rats with similar lesions and postoperative recovery times but no grafts. Rats tested immediately after receiving implants performed better on the spatial navigation task than rats with similar lesions but no grafts. This improvement, however, was less than that shown by rats with lesions but no grafts permitted to recover for 28 days before testing. In contrast, in the Delay Group, rats with grafts were more greatly impaired than were their operated controls. Neither lesions nor grafts affected grooming although the Immediate Group with grafts were significantly more impaired in using their forepaws during feeding than were any of the other groups. These results lead us to conclude that differing postoperative recovery times and task requirements may account for some of the inconsistent results of the influence of brain grafts on behavioral recovery reported in the literature. We also conclude that cortical tissue implants can have two effects with different time courses and opposite net behavioral effects.

Adult male Long-Evans rats (90 days of age) were housed in 12 h light :12 h dark (Group LD), constant white light (Group LL), or constant dark (dim red light) (Group DD) for 60\p=n-\90 days. The first of two sexual behaviour tests revealed that more (P < 0\m=.\05) rats in Group LD achieved intromission than did those in Groups LL and DD. Only 33% of Group LL and 32% of Group DD rats ejaculated. In contrast, all Group LD rats that mounted eventually ejaculated. Males in Group LD achieved more (P < 0\m=.\05)ejaculations (mean of both tests combined, 3\m=.\4) than did males in Groups LL (1 \ m=. \ 5) or DD (1\m=.\2).Although there were no notable differences amongst the groups in the weights of the accessory sex organs, males in Group DD had higher (P < 0\m=.\05) serum androgen levels than did those in Groups LL and LD while Group LL males had higher (P < 0\m=.\05) serum prolactin levels than did those in Groups LD and DD. There were no differences in LH or FSH levels. In addition, more rats in Group LL had disrupted activity rhythms than did Group DD rats. These results indicate that housing in constant white or dim red light disrupts sexual behaviour in male rats and may do so through different neuroendocrine mechanisms.

We studied the effect of different postoperative times on the behavioral recovery following brain implants. Adult male rats received cortical tissue grafts 2 weeks after aspiration of the medial frontal cortex. Either 2 (Immediate Group) or 28 (Delay Group) days after grafting, the performance of these rats on a behavioral battery, comprising the Morris water maze task, forepaw use, and grooming, was compared to that of rats with similar lesions and postoperative recovery times but no grafts. Rats tested immediately after receiving implants performed better on the spatial navigation task than rats with similar lesions but no grafts. This improvement, however, was less than that shown by rats with lesions but no grafts permitted to recover for 28 days before testing. In contrast, in the Delay Group, rats with grafts were more greatly impaired than were their operated controls. Neither lesions nor grafts affected grooming although the Immediate Group with grafts were significantly more impaired in using their forepaws during feeding than were any of the other groups. These results lead us to conclude that differing postoperative recovery times and task requirements may account for some of the inconsistent results of the influence of brain grafts on behavioral recovery reported in the literature. We also conclude that cortical tissue implants can have two effects with different time courses and opposite net behavioral effects.

Objective: Findings on spatial memory in depression have been inconsistent. A navigation task based on virtual reality may provide a more sensitive and consistent measure of the hippocampal-related spatial memory deficits associated with depression. Of great value for endophenotype studies in psychiatric disorders will be an understanding of the neuroanatomical and functional relationships between neuropsychological deficits and brain structure abnormalities (1). Neuropsychological testing has long established the presence of memory deficits in patients with unipolar depression and, more recently, in those suffering from bipolar depression (see reference 2 for a review). Owing to the role of the hippocampus (3), spatial memory may be of particular interest because of reports of hippocampal volume

Regarding the notion of putative &ldquo;best&rdquo; practices in social neuroscience and science in general, we contend that following established procedures has advantages, but prescriptive uniformity in methodology can obscure flaws, bias thinking, stifle creativity, and restrict exploration. Generating hypotheses is at least as important as testing hypotheses. To illustrate this process, we describe the following exploratory study. Psychiatric patients have difficulties with social functioning that affect their quality of life adversely. To investigate these impediments, we compared the performances of patients with schizophrenia and those with bipolar disorder to healthy controls on a task that involved matching photographs of facial expressions to a faceless protagonist in each of a series of drawn cartoon emotion-related situations. These scenarios involved either a single character (Nonsocial) or multiple characters (Social). The Social scenarios were also Congruent, with eve...

Elevated blood homocysteine (Hcy) among middle-aged adults can increase age-related disease risk, possibly through other biochemical and hematological markers. We selected markers for hyperhomocysteinemia among middle-aged adults, studied time-dependent Hcy-marker associations and computed highly predictive indices of hyperhomocysteinemia, with cross-sectional and longitudinal validations. We used data from the National Health and Nutrition Examination Survey (NHANES III, phase 2, n max = 4000), the NHANES 1999-2006 (n max = 10,151) and pooled NHANES (cross-sectional validation). Longitudinal validation consisted of mixed-effects linear regression models (Hcy predicting markers' annual rates of change), applied to the Healthy Aging in Neighborhoods of Diversity Across the Life Span (HANDLS, n = 227-244 participants, k = 2.4 repeats/participant, Age base : 30-65 years) data. Machine learning detected nine independent markers for Hcy > 14 µmol/L (NHANES III, phase 2): older age; lower folate and B-12 status; higher serum levels of creatinine, uric acid, alkaline phosphatase, and cotinine; mean cell hemoglobin and red cell distribution widths (RDW); results replicated in the 1999-2006 NHANES [AUC = 0.60-0.80]. Indices combining binary markers increased elevated Hcy odds by 6.9-7.5-fold. In HANDLS, first-visit Hcy predicted annual increase in creatinine, RDW and alkaline phosphatase, with third-visit index (2013-2018) directly predicting Hcy (2004-2009). We provide evidence of the internal and external validity of indices composed of several biomarkers that are strongly associated with elevated Hcy.

Background: Anemia and red cell distribution width (RDW) have been linked to poor cognitive performance, pending studies of underlying mechanisms. Objective: We examined cross-sectional relationships of initial RDW status (v 1), RDW change (δ), and anemia with brain structural magnetic resonance imaging (sMRI) markers, including global and cortical brain and hippocampal and white matter lesion (WML) volumes, 5-6 years later. Methods: Data were used from three prospective visits within the Healthy Aging in Neighborhoods of Diversity Across the Life Span (HANDLS) study with complete v 1 (2004-2009) and v 2 (2009-2013) exposures and ancillary sMRI data at v scan (2011-2015, n = 213, mean v 1 to v scan time: 5.7 years). Multivariable-adjusted linear regression models were conducted, overall, by sex, by race, and within non-anemics, correcting for multiple testing with q-values. Results: In minimally adjusted models (socio-demographics and follow-up time), anemia v1 and RDW v1 were consistently associated with smaller bilateral hippocampal volumes overall, and among females (q < 0.05), without significant sex differences. RDW v1 was related to smaller select regional cortical brain gray and white matter volumes in hematological measure-adjusted models; anemia v1 was associated with larger WML volumes only among Whites.

showed that when choice is between variable (risky) and fixed (safe) food amounts with the same expected values, capuchins prefer the safe alternative if choice is framed as a gain, but the risky alternative if it is framed as a loss. These results seem similar to those seen in human prospect-theory tests in choice between variable and fixed gains or losses. Based on this similarity, they interpreted their results as identifying a between-species commonality in cognitive function. In this report, we repeat their experiment with humans as subjects (an up-linkage replication). Whether choices were rewarded with candy or nickels, choice approximated indifference whether framed as gains or losses. Our data mirror those of others who found that when humans make risky choices within a repeated-trials procedure without verbal instruction about outcome likelihoods, preference biases seen in one-shot, language-guided, prospect-theory tests such as Tversky and Kahneman's (Science 211:453-458, 1981) reflection effect may not appear. The disparity between our findings and those of Lakshminarayanan et al. suggests their study does not evidence a cognitive process shared by humans and capuchins.