Papers by Rosemary Varley
Proceedings of the National Academy of Sciences of the United States of America, 2005
A central question in cognitive neuroscience concerns the extent to which language enables other ... more A central question in cognitive neuroscience concerns the extent to which language enables other higher cognitive functions. In the case of mathematics, the resources of the language faculty, both lexical and syntactic, have been claimed to be important for exact calculation, and some functional brain imaging studies have shown that calculation is associated with activation of a network of left-hemisphere language regions, such as the angular gyrus and the banks of the intraparietal sulcus. We investigate the integrity of mathematical calculations in three men with large left-hemisphere perisylvian lesions. Despite severe grammatical impairment and some difficulty in processing phonological and orthographic number words, all basic computational procedures were intact across patients. All three patients solved mathematical problems involving recursiveness and structure-dependent operations (for example, in generating solutions to bracket equations). To our knowledge, these results de...
Nature reviews. Neuroscience, 2002
What is the nature of our ability to understand and reason about the beliefs of others--the posse... more What is the nature of our ability to understand and reason about the beliefs of others--the possession of a "theory of mind", or ToM? Here, we review findings from imaging and lesion studies indicating that ToM reasoning is supported by a widely distributed neural system. Some functional components of this system, such as language-related regions of the left hemisphere, the frontal lobes and the right temporal parietal cortex, are not solely dedicated to the computation of mental states. However, the system also includes a core, domain-specific component that is centred on the amygdala circuitry. We provide a framework in which impairments of ToM can be viewed in terms of abnormalities of the core system, the failure of a co-opted system that is necessary for performance on a particular set of tasks, or the absence of an experiential trigger for the emergence of ToM.
International Journal of Language & Communication Disorders, 1995
This paper reports on the use of electropalatography (EPG) in the treatment of a patient with sev... more This paper reports on the use of electropalatography (EPG) in the treatment of a patient with severe acquired apraxia of speech. A t 2 yeam post-onset and afier a period of conventional speech and language therapy, the patient, AD, presented with severe speech production problems affecting articulation, phonation and resonance. Treatment using EPG is described and both the patient's progress and his continued limitations are outlined. EPG provided a valuable form of visual feedback for the patient and revealed and clarified aspects of oral movements for speech and non-speech activity which had been difficult to capture via auditory perception.
Understanding the inter-relationship between language and thought is fundamental to the study of ... more Understanding the inter-relationship between language and thought is fundamental to the study of human cognition [1-3]. Some investigators have proposed that propositions in natural language serve to scaffold thinking, by providing, for example, a sequential structure to a massively parallel process [4]. Others have maintained that certain thoughts, such as inferring the mental states of others, termed 'theory of mind' (ToM) reasoning, and identifying causal relationships, necessarily involve language propositions [5]. It has been proposed that ToM reasoning depends upon the possession of syntactic structures such as those that permit the embedding of false propositions within true statements ('Mary knows that John (falsely) thinks chocolates are in the cupboard') [6]. The performance on reasoning tasks of individuals with severe agrammatic aphasia (an impairment of language following a lesion of the perisylvian areas of the language-dominant hemisphere) offers novel insights into the relation between grammar and cognition. We report the unusual case of a patient with agrammatic aphasia of such severity that language propositions were not apparently available at an explicit processing level in any modality of language use. Despite this profound impairment in grammar, he displayed simple causal reasoning and ToM understanding. Thus, reasoning about causes and beliefs involve processes that are independent of propositional language.
ABSTRACT We examine Carruthers’ proposal that sentences in logical form serve to create flexibili... more ABSTRACT We examine Carruthers’ proposal that sentences in logical form serve to create flexibility within central system modularity, enabling the combination of information from different modalities. We discuss evidence from aphasia and the neurobiology of input-output systems. This work suggests that there exists considerable capacity for interdomain cognitive processing without language mediation. Other challenges for a logical form account are noted.
A central question in cognitive neuroscience concerns the extent to which language enables other ... more A central question in cognitive neuroscience concerns the extent to which language enables other higher cognitive functions. In the case of mathematics, the resources of the language faculty, both lexical and syntactic, have been claimed to be important for exact calculation, and some functional brain imaging studies have shown that calculation is associated with activation of a network of left-hemisphere language regions, such as the angular gyrus and the banks of the intraparietal sulcus. We investigate the integrity of mathematical calculations in three men with large left-hemisphere perisylvian lesions. Despite severe grammatical impairment and some difficulty in processing phonological and orthographic number words, all basic computational procedures were intact across patients. All three patients solved mathematical problems involving recursiveness and structure-dependent operations (for example, in generating solutions to bracket equations). To our knowledge, these results demonstrate for the first time the remarkable independence of mathematical calculations from language grammar in the mature cognitive system. aphasia ͉ language ͉ mathematics
We report the case of a left-handed man (MCR), who presented with a peripheral agraphia as an ear... more We report the case of a left-handed man (MCR), who presented with a peripheral agraphia as an early sign of multiple sclerosis. His left-handed writing was neologistic, whilst oral spelling, typing and spelling with the right hand were intact. Structural MRI scanning revealed a lesion of the body of the corpus callosum. Dichotic listening tests indicated that MCR displayed left hemisphere dominance for language. It is proposed that MCR represents a case of a disconnection syndrome in which right hemisphere systems that provide the basis for movement templates during left-handed writing are isolated from left hemisphere language systems. Analysis of left-handed writing indicated that peripheral movement control was highly structured with both individual letter frequency and sequential dependencies between letters represented within these motor control units. This case represents an opportunity to explore the mechanisms of movement control for writing and to examine the characteristics of isolated letter templates.
Procedia - Social and Behavioral Sciences, 2010
The human capacity to communicate has been hypothesized to be causally dependent upon language. I... more The human capacity to communicate has been hypothesized to be causally dependent upon language. Intuitively this seems plausible since most communication relies on language. Moreover, intention recognition abilities (as a necessary prerequisite for communication) and language development seem to co-develop. Here we review evidence from neuroimaging as well as from neuropsychology to evaluate the relationship between communicative and linguistic abilities. Our review indicates that communicative abilities are best considered as neurally distinct from language abilities. This conclusion is based upon evidence showing that humans rely on different cortical systems when designing a communicative message for someone else as compared to when performing core linguistic tasks, as well as upon observations of individuals with severe language loss after extensive lesions to the language system, who are still able to perform tasks involving intention understanding.
Communication impairments such as aphasia and apraxia can follow brain injury and result in limit... more Communication impairments such as aphasia and apraxia can follow brain injury and result in limitation of an individual's participation in social interactions, and capacity to convey needs and desires. Our research group developed a computerized treatment program which is based on neuroscientific principles of speech production and has been shown to improve communication in people with apraxia and aphasia ). Investigations of treatment efficacy have presented challenges in study design, effect measurement, and statistical analysis which are likely to be shared by other researchers in the wider field of cognitive neurorehabilitation evaluation. Several key factors define neurocognitively based therapies, and differentiate them and their evaluation from other forms of medical intervention. These include: (1) inability to "blind" patients to the content of the treatment and control procedures; (2) neurocognitive changes that are more permanent than pharmacological treatments on which many medical study designs are based; and (3) the semi-permanence of therapeutic effects means that new baselines are set throughout the course of a given treatment study, against which comparative interventions or long term retention effects must be measured. This article examines key issues in study design, effect measurement, and data analysis in relation to the rehabilitation of patients undergoing treatment for apraxia of speech. Results from our research support a case for the use of multiperiod, multiphase cross-over design with specific computational adjustments and statistical considerations. The paper provides researchers in the field with a methodologically feasible and statistically viable alternative to other designs used in rehabilitation sciences.
Although there is evidence that exact calculation recruits left hemisphere perisylvian language s... more Although there is evidence that exact calculation recruits left hemisphere perisylvian language systems, recent work has shown that exact calculation can be retained despite severe damage to these networks. In this study, we sought to identify a "core" network for calculation and hence to determine the extent to which left hemisphere language areas are part of this network. We examined performance on addition and subtraction problems in two modalities: one using conventional two-digit problems that can be easily encoded into language; the other using novel shape representations. With regard to numerical problems, our results revealed increased left fronto-temporal activity in addition, and increased parietal activity in subtraction, potentially reflecting retrieval of linguistically encoded information during addition. The shape problems elicited activations of occipital, parietal and dorsal temporal regions, reflecting visual reasoning processes. A core activation common to both calculation types involved the superior parietal lobule bilaterally, right temporal sub-gyral area, and left lateralized activations in inferior parietal (BA 40), frontal (BA 6/8/32) and occipital (BA 18) regions. The large bilateral parietal activation could be attributed to visuo-spatial processing in calculation. The inferior parietal region, and particularly the left angular gyrus, was part of the core calculation network. However, given its activation in both shape and number tasks, its role is unlikely to reflect linguistic processing per se. A possibility is that it serves to integrate right hemisphere visuo-spatial and left hemisphere linguistic and executive processing in calculation.
Language has been proposed as a medium that serves to promote spatial orientation through integra... more Language has been proposed as a medium that serves to promote spatial orientation through integrating geometric and featural information (Spelke, 2003). This proposal has been explored in dual-task experiments where linguistic resources are blocked by verbal shadowing. Although some studies report disruption in using environmental cues for spatial reorientation, findings have not been consistently replicated, and the source of disruption to reorientation by verbal shadowing remains unclear. We examined conditions under which verbal shadowing affects reorientation. Shadowing of meaningful language disrupted healthy adults' use of geometric and featural information to reorient only when task instructions were unclear and when extraneous visual information provided a source of nonlinguistic interference. Reorientation was examined during the shadowing of meaningful prose or nonword syllables and was similar under both concurrent task conditions. These results indicate that language is not necessary for spatial cue integration.
Trends in Cognitive Sciences, 2001
Research on propositional reasoning (involving 'theory of mind' understanding) in adult patients ... more Research on propositional reasoning (involving 'theory of mind' understanding) in adult patients with aphasia reveals that reasoning can proceed in the absence of explicit grammatical knowledge. Conversely, evidence from studies with deaf children shows that the presence of such knowledge is not sufficient to account for reasoning. These findings are in keeping with recent research on the development of naming, categorization and imitation, indicating that children's reasoning about objects and actions is guided by inferences about others' communicative intentions. We discuss the extent to which reasoning is supported by, and tied to, language in the form of conversational awareness and experience rather than grammar.
Neuropsychologia, 2007
We report a dissociation between higher order mathematical ability and language in the case of a ... more We report a dissociation between higher order mathematical ability and language in the case of a man (SO) with severe aphasia. Despite severely impaired abilities in the language domain and difficulties with processing both phonological and orthographic number words, he was able to judge the equivalence of and to transform and simplify mathematical expressions in algebraic notation. SO was sensitive to structure-dependent properties of algebraic expressions and displayed considerable capacity to retrieve algebraic facts, rules and principles, and to apply them to novel problems. He demonstrated similar capacity in solving expressions containing either solely numeric or abstract algebraic symbols (e.g., 8 − (3 − 5) + 3 versus b − (a − c) + a). The results show the retention of elementary algebra despite severe aphasia and provide evidence for the preservation of symbolic capacity in one modality and hence against the notion of aphasia as asymbolia.
Neurocase, 2001
Understanding the inter-relationship between language and thought is fundamental to the study of ... more Understanding the inter-relationship between language and thought is fundamental to the study of human cognition [1-3]. Some investigators have proposed that propositions in natural language serve to scaffold thinking, by providing, for example, a sequential structure to a massively parallel process [4]. Others have maintained that certain thoughts, such as inferring the mental states of others, termed 'theory of mind' (ToM) reasoning, and identifying causal relationships, necessarily involve language propositions [5]. It has been proposed that ToM reasoning depends upon the possession of syntactic structures such as those that permit the embedding of false propositions within true statements ('Mary knows that John (falsely) thinks chocolates are in the cupboard') [6]. The performance on reasoning tasks of individuals with severe agrammatic aphasia (an impairment of language following a lesion of the perisylvian areas of the language-dominant hemisphere) offers novel insights into the relation between grammar and cognition. We report the unusual case of a patient with agrammatic aphasia of such severity that language propositions were not apparently available at an explicit processing level in any modality of language use. Despite this profound impairment in grammar, he displayed simple causal reasoning and ToM understanding. Thus, reasoning about causes and beliefs involve processes that are independent of propositional language.
Memory & Cognition, 2011
Artificial grammar learning (AGL) is a widely used experimental paradigm that investigates how sy... more Artificial grammar learning (AGL) is a widely used experimental paradigm that investigates how syntactic structures are processed. After a familiarization phase, participants have to distinguish strings consistent with a set of grammatical rules from strings that violate these rules. Many experiments report performance solely at a group level and as the total number of correct judgments. This report describes a systematic approach for investigating individual performance and a range of different behaviors. Participants were exposed to strings of the nonfinite grammar A n B n . To distinguish grammatical from ungrammatical strings, participants had to pay attention to local dependencies while comparing the number of stimuli from each class. Individual participants showed substantially different behavioral patterns despite exposure to the same stimuli. The results were replicated across auditory and visual sensory modalities. It is suggested that an analysis that looks at individual differences grants new insights into the processes involved in AGL. It also provides a solid basis from which to investigate sequenceprocessing abilities in special populations, such as patients with neurological lesions.
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Papers by Rosemary Varley