Biomedical subjects

Jill Boucher

Publications and source records attributed to Jill Boucher.

8 recordsLinked to original sources

PubMed2005

Gamma abnormalities during perception of illusory figures in autism.

This experiment was designed to test the hypothesis that perceptual abnormalities in autism might be associated with alteration of induced gamma activity patterns overlying visual cortical regions. EEG was recorded from six adolescents with autism and eight controls matched on chronological age, and verbal and nonverbal mental age, whilst identifying the presence or absence of an illusory Kanizsa shape. Although there were no reaction time or accuracy differences between the groups there were significant task-related differences in cortical activity. Control participants showed typical gamma-band activity over parietal regions at around 350 msec post onset of shape trials, similar to gamma patterns found in previous studies with non-impaired adults. In contrast, autistic participants showed overall increased activity, including an early 100 msec gamma peak and a late induced peak, 50 to 70 msec earlier than that shown by the control group. We interpret the abnormal gamma activity to reflect decreased "signal to noise" due to decreased inhibitory processing. In this experiment we did not establish a link between altered perception and abnormal gamma, as the autistic participants' behaviour did not differ from the controls. Future work should be designed to replicate this phenomenon and establish the perceptual consequences of altered gamma activity.

Adolescent↗

PubMed2005

Probed serial recall in Williams syndrome: lexical influences on phonological short-term memory.

Williams syndrome is a genetic disorder that, it has been claimed, results in an unusual pattern of linguistic strengths and weaknesses. The current study investigated the hypothesis that there is a reduced influence of lexical knowledge on phonological short-term memory in Williams syndrome. Fourteen children with Williams syndrome and 2 vocabulary-matched control groups, 20 typically developing children and 13 children with learning difficulties, were tested on 2 probed serial-recall tasks. On the basis of previous findings, it was predicted that children with Williams syndrome would demonstrate (a) a reduced effect of lexicality on the recall of list items, (b) relatively poorer recall of list items compared with recall of serial order, and (c) a reduced tendency to produce lexicalization errors in the recall of nonwords. In fact, none of these predictions were supported. Alternative explanations for previous findings and implications for accounts of language development in Williams syndrome are discussed.

Adolescent↗

PubMed2005

Moral understanding in children with autism.

Children with autism were compared with control groups on their ability to make moral judgements. Participants were presented with pairs of vignettes in which actions were either deliberate or accidental and caused injury to a person or damage to property. Participants were asked to judge which protagonist was the naughtier and to verbally justify this judgement. Results showed that the children with autism were as likely as controls to judge culpability on the basis of motive, and to judge injury to persons as more culpable than damage to property. Children with autism also offered some appropriate verbal justifications for their judgments although most justifications were of poor quality and reiterated the story. Results are discussed in terms of theory of mind and the possible role of deficits in complex reasoning and executive functions.

Autistic Disorder↗

PubMed2004

Counterfactual and mental state reasoning in children with autism.

The contributions of counterfactual conditional reasoning (CCR), belief understanding, and inferential reasoning to the performance of children with autism (CWA) on standard false belief tasks were investigated. To assess the roles of these three factors, we compared the performance of CWA on physical-state CCR tasks (which do not require either an understanding of belief or inferential reasoning); on Wellman and Bartsch's (1988) nonstandard tests of false belief (which require an understanding of belief, but not CCR or inferential reasoning), and on standard tests of false belief tasks. The CWA were impaired relative to controls on the physical-state CCR and standard false-belief tasks, but not on the nonstandard false-belief tasks, and the CWA's performance on the physical-state CCR and standard false-belief tasks correlated highly, even when the effects of verbal ability were partialled out. Finally, the CWA's performance on standard false-belief tasks was more impaired than their performance on the physical-state CCR tasks. We concluded that impaired performance on standard false-belief tasks in autism is associated with defective competence in CCR (or some of its component skills), plus defective competence in inferential reasoning and possibly generativity, but that impaired performance is not caused by an inadequate understanding of belief. The results are discussed in relation to other hypotheses concerning the cause or causes of impaired performance on standard false-belief tasks in children with autism.

Autistic Disorder↗

PubMed2003

Language development in autism.

In this short review article, a summary of the behavioural impairments most commonly associated with the spectrum of autism-related disorders is presented, with a slightly amplified account of the defining communication impairment. The patterns of language ability and disability which typically occur in some forms of autism are then outlined, followed by a short section on possible cognitive, or psychological, explanations of these patterns. In particular, the hypothesis that defective socio-affective and socio-cognitive ('theory of mind') causes language impairments, and the hypothesis that temporal processing deficits cause these impairments, are outlined and briefly discussed. An extensive list of references is included, to support and amplify the summary data included in the review.

Autistic Disorder↗

PubMed2003

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Autistic Disorder↗

PubMed2002

The temporal binding deficit hypothesis of autism.

Frith has argued that people with autism show "weak central coherence," an unusual bias toward piecemeal rather than configurational processing and a reduction in the normal tendency to process information in context. However, the precise cognitive and neurological mechanisms underlying weak central coherence are still unknown. We propose the hypothesis that the features of autism associated with weak central coherence result from a reduction in the integration of specialized local neural networks in the brain caused by a deficit in temporal binding. The visuoperceptual anomalies associated with weak central coherence may be attributed to a reduction in synchronization of high-frequency gamma activity between local networks processing local features. The failure to utilize context in language processing in autism can be explained in similar terms. Temporal binding deficits could also contribute to executive dysfunction in autism and to some of the deficits in socialization and communication.

Attention↗

PubMedDate not supplied

The interactional significance of formulas in autistic language.

The phenomenon of echolalia in autistic language is well documented. Whilst much early research dismissed echolalia as merely an indicator of cognitive limitation, later work identified particular discourse functions of echolalic utterances. The work reported here extends the study of the interactional significance of echolalia to formulaic utterances. Audio and video recordings of conversations between the first author and two research participants were transcribed and analysed according to a Conversation Analysis framework and a multi-layered linguistic framework. Formulaic language was found to have predictable interactional significance within the language of an individual with autism, and the generic phenomenon of formulaicity in company with predictable discourse function was seen to hold across the research participants, regardless of cognitive ability. The implications of formulaicity in autistic language for acquisition and processing mechanisms are discussed.

Adult↗