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Biomedical subjects

Uta Frith

Publications and source records attributed to Uta Frith.

At least 19 recordsLinked to original sources

More than words: a common neural basis for reading and naming deficits in developmental dyslexia?

Dyslexic individuals show subtle impairments in naming pictures of objects in addition to their difficulties with reading. The present study investigated whether word reading and picture naming deficits in developmental dyslexia can be reduced to a common neurological impairment. Eight dyslexic subjects, impaired on measures of reading, spelling and naming speed, were matched for age and general ability with 10 control subjects. Participants were scanned using PET during two experimental conditions: reading words and naming pictures in the form of corresponding line drawings. In addition, two high-level baseline conditions were used to control for visual and articulatory processes. Relative to the control group, the dyslexic participants showed reduced activation in a left occipitotemporal area during both word reading and picture naming. This was the case even in the context of intact behavioural performance during scanning. Abnormal activation in this region, as reported previously for reading, is therefore not specific to orthographic decoding but may reflect a more general impairment in integrating phonology and visual information. Our investigation points to a common neurological basis for deficits in word reading and picture naming in developmental dyslexia.

Adolescent↗

Your own action influences how you perceive another person's action.

A growing body of neuroimaging and neurophysiology studies has demonstrated the motor system's involvement in the observation of actions, but the functional significance of this is still unclear. One hypothesis suggests that the motor system decodes observed actions. This hypothesis predicts that performing a concurrent action should influence the perception of an observed action. We tested this prediction by asking subjects to judge the weight of a box lifted by an actor while the subject either lifted or passively held a light or heavy box. We found that actively lifting a box altered the perceptual judgment; an observed box was judged to be heavier when subjects were lifting the light box, and it was judged to be lighter when they were lifting the heavy box. This result is surprising because previous studies have found facilitating effects of movement on perceptual judgments and facilitating effects of observed actions on movements, but here we found the opposite. We hypothesize that this effect can be understood in terms of overlapping neural systems for motor control and action-understanding if multiple models of possible observed and performed actions are processed.

Adult↗

The impact of extensive medial frontal lobe damage on 'Theory of Mind' and cognition.

The ability of humans to predict and explain other people's behaviour by attributing to them independent mental states, such as desires and beliefs, is considered to be due to our ability to construct a 'Theory of Mind'. Recently, several neuroimaging studies have implicated the medial frontal lobes as playing a critical role in a dedicated 'mentalizing' or 'Theory of Mind' network in human brains. Here, we report a patient, G.T., who suffered an exceptionally rare form of stroke-bilateral anterior cerebral artery infarction, without rupture or the complications associated with anterior communicating artery aneurysms. Detailed high-resolution neuroanatomical investigations revealed extensive damage to the medial frontal lobes bilaterally, including regions identified to be critical for 'Theory of Mind' by functional neuroimaging of healthy human subjects. For the first time in such a patient, we carried out a thorough assessment of her cognitive profile including, critically, an experimental investigation of her performance on a range of tests of 'Theory of Mind'. G.T. had a dysexecutive syndrome characterized by impairments in planning and memory, as well as a tendency to confabulate. Importantly, however, she did not have any significant impairment on tasks probing her ability to construct a 'Theory of Mind', demonstrating that the extensive medial frontal regions destroyed by her stroke are not necessary for this function. These findings have important implications for the functional anatomy of 'Theory of Mind', as well as our understanding of medial frontal function. Possible reasons for the discrepancies between our results and neuroimaging studies are discussed. We conclude that our findings urge caution against using functional imaging as the sole method of establishing cognitive neuroanatomy.

Cognition Disorders↗

How does the brain deal with the social world?

It is only relatively recently that the search for the biological basis of social cognition has started. It is still unknown just how biological factors, from genes to brain processes, interact with environmental variables to produce individual differences in social competence and in pathology of social communication. It may seem over-ambitious to work out how connections can be made between sophisticated social behaviour and basic neurophysiological mechanisms. However, examples already exist. The neural basis of social processes such as deception and morality are now being studied by cognitive neuroscientists. In this review, we summarize recent work that has illuminated the neuro-cognitive basis of complex social interaction and communication in humans.

Animals↗

Social cognitive neuroscience: where are we heading?

Humans crave the company of others and suffer profoundly if temporarily isolated from society. Much of the brain must have evolved to deal with social communication and we are increasingly learning more about the neurophysiological basis of social cognition. Here, we explore some of the reasons why social cognitive neuroscience is captivating the interest of many researchers. We focus on its future, and what we believe are priority areas for further research.

Bayes Theorem↗

Brief report: cognitive processing of own emotions in individuals with autistic spectrum disorder and in their relatives.

Difficulties in the cognitive processing of emotions--including difficulties identifying and describing feelings--are assumed to be an integral part of autism. We studied such difficulties via self-report in 27 high-functioning adults with autistic spectrum disorders, their biological relatives (n = 49), and normal adult controls (n = 35), using the 20-item Toronto Alexithymia Scale and the Beck Depression Inventory. The individuals with autism spectrum disorders were significantly more impaired in their emotion processing and were more depressed than those in the control and relative groups.

Adolescent↗

Emanuel Miller lecture: confusions and controversies about Asperger syndrome.

BACKGROUND: Hans Asperger drew attention to individuals who show the core symptoms of autism in the presence of high verbal intelligence. METHODS: A review of the literature explores current issues concerning the diagnosis and nature of Asperger syndrome. RESULTS: The behavioural and neurophysiological evidence to date suggests that Asperger syndrome is a variant of autism typically occurring in high-functioning individuals, and not a separate disorder. One of the problems of diagnosis is that the typical impairment of social communication may be difficult to identify in early childhood, and can be camouflaged in adulthood by compensatory learning. The range and nature of the social impairments in Asperger syndrome are still in need of investigation, but appear to be less severe than in autism. Experimental evidence suggests that individuals with Asperger syndrome may lack an intuitive theory of mind (mentalising), but may be able to acquire an explicit theory of mind. Brain imaging studies pinpoint a network that links medial prefrontal and temporal cortex as the neural substrate of intuitive mentalising. This network shows reduced activation and poor connectivity in Asperger syndrome. While some individuals with Asperger syndrome have written eloquently about their lives, their ability to talk about their own emotions appears to be impaired (alexithymia). This impairment may be linked to depression and anxiety, which is common in adulthood. Little is as yet known about the often considerable cognitive strengths in Asperger syndrome, or about the difficulties observed in higher-level executive skills. CONCLUSIONS: Studies are needed that define the developmental course of the disorder and the nature of the strengths and weaknesses in both social and non-social domains. This requires more sensitive assessment instruments than are currently available. Questions about the prevalence of Asperger syndrome, about associated and secondary features, and about optimal education and management, urgently call for such studies.

Adolescent↗

Reading music modifies spatial mapping in pianists.

We used a novel musical Stroop task to demonstrate that musical notation is automatically processed in trained pianists. Numbers were superimposed onto musical notes, and participants played five-note sequences by mapping from numbers to fingers instead of from notes to fingers. Pianists' reaction times were significantly affected by the congruence of the note/number pairing. Nonmusicians were unaffected. In a nonmusical analogue of the task, pianists and nonmusicians showed a qualitative difference on performance of a vertical-to-horizontal stimulus-response mapping task. Pianists were faster when stimuli specifying a leftward response were presented in vertically lower locations and stimuli specifying a rightward response were presented in vertically higher locations. Nonmusicians showed the reverse pattern. No group differences were found on a task that required horizontal-to-horizontal mappings. We suggest that, as a result of learning to read and play keyboard music, pianists acquire vertical-to-horizontal visuomotor mappings that generalize outside the musical context.

Adolescent↗

"Hey John": signals conveying communicative intention toward the self activate brain regions associated with "mentalizing," regardless of modality.

Successful communication between two people depends first on the recognition of the intention to communicate. Such intentions may be conveyed by signals directed at the self, such as calling a person's name or making eye contact. In this study we use functional magnetic resonance imaging to show that the perception of these two signals, which differ in modality and sensory channel, activate common brain regions: the paracingulate cortex and temporal poles bilaterally. These regions are part of a network that has been consistently activated when people are asked to think about the mental states of others. Activation of this network is independent of arousal as measured by changes in pupil diameter.

Acoustic Stimulation↗

Development and neurophysiology of mentalizing.

The mentalizing (theory of mind) system of the brain is probably in operation from ca. 18 months of age, allowing implicit attribution of intentions and other mental states. Between the ages of 4 and 6 years explicit mentalizing becomes possible, and from this age children are able to explain the misleading reasons that have given rise to a false belief. Neuroimaging studies of mentalizing have so far only been carried out in adults. They reveal a system with three components consistently activated during both implicit and explicit mentalizing tasks: medial prefrontal cortex (MPFC), temporal poles and posterior superior temporal sulcus (STS). The functions of these components can be elucidated, to some extent, from their role in other tasks used in neuroimaging studies. Thus, the MPFC region is probably the basis of the decoupling mechanism that distinguishes mental state representations from physical state representations; the STS region is probably the basis of the detection of agency, and the temporal poles might be involved in access to social knowledge in the form of scripts. The activation of these components in concert appears to be critical to mentalizing.

Child, Preschool↗

Understanding autism: insights from mind and brain.

Autism is a developmental disorder characterized by impaired social interaction and communication as well as repetitive behaviours and restricted interests. The consequences of this disorder for everyday life adaptation are extremely variable. The general public is now more aware of the high prevalence of this lifelong disorder, with ca. 0.6% of the population being affected. However, the signs and symptoms of autism are still puzzling. Since a biological basis of autism was accepted, approaches from developmental cognitive neuroscience have been applied to further our understanding of the autism spectrum. The study of the behavioural and underlying cognitive deficits in autism has advanced ahead of the study of the underlying brain abnormalities and of the putative genetic mechanisms. However, advances in these fields are expected as methodological difficulties are overcome. In this paper, recent developments in the field of autism are outlined. In particular, we review the findings of the three main neuro-cognitive theories of autism: theory-of-mind deficit, weak central coherence and executive dysfunction.

Autistic Disorder↗

Brain changes after learning to read and play music.

Musically naive participants were scanned before and after a period of 15 weeks during which they were taught to read music and play the keyboard. When participants played melodies from musical notation after training, activation was seen in a cluster of voxels within the bilateral superior parietal cortex. A subset of these voxels were activated in a second experiment in which musical notation was present, but irrelevant for task performance. These activations suggest that music reading involves the automatic sensorimotor translation of a spatial code (written music) into a series of motor responses (keypresses).

Adult↗

Theories of developmental dyslexia: insights from a multiple case study of dyslexic adults.

A multiple case study was conducted in order to assess three leading theories of developmental dyslexia: (i) the phonological theory, (ii) the magnocellular (auditory and visual) theory and (iii) the cerebellar theory. Sixteen dyslexic and 16 control university students were administered a full battery of psychometric, phonological, auditory, visual and cerebellar tests. Individual data reveal that all 16 dyslexics suffer from a phonological deficit, 10 from an auditory deficit, four from a motor deficit and two from a visual magnocellular deficit. Results suggest that a phonological deficit can appear in the absence of any other sensory or motor disorder, and is sufficient to cause a literacy impairment, as demonstrated by five of the dyslexics. Auditory disorders, when present, aggravate the phonological deficit, hence the literacy impairment. However, auditory deficits cannot be characterized simply as rapid auditory processing problems, as would be predicted by the magnocellular theory. Nor are they restricted to speech. Contrary to the cerebellar theory, we find little support for the notion that motor impairments, when found, have a cerebellar origin or reflect an automaticity deficit. Overall, the present data support the phonological theory of dyslexia, while acknowledging the presence of additional sensory and motor disorders in certain individuals.

Adult↗

The relationship between motor control and phonology in dyslexic children.

BACKGROUND: The goal of this study was to investigate the automaticity/cerebellar theory of dyslexia. We tested phonological skills and cerebellar function in a group of dyslexic 8-12-year-old children and their matched controls. Tests administered included the Phonological Assessment Battery, postural stability, bead threading, finger to thumb and time estimation. RESULTS: Dyslexic children were found to be significantly poorer than the controls at all tasks but time estimation. About 77% of dyslexics were more than one standard deviation below controls in phonological ability, and 59% were similarly impaired in motor skills. However, at least part of the discrepancy in motor skills was due to dyslexic individuals who had additional disorders (ADHD and/or DCD). The absence of evidence for a time estimation deficit also casts doubt on the cerebellar origin of the motor deficiency. About half the dyslexic children didn't have any motor problem, and there was no evidence for a causal relationship between motor skills on the one hand and phonological and reading skills on the other. CONCLUSION: This study provides partial support for the presence of motor problems in dyslexic children, but does not support the hypothesis that a cerebellar dysfunction is the cause of their phonological and reading impairment.

Attention Deficit Disorder with Hyperactivity↗

Becoming a pianist. An fMRI study of musical literacy acquisition.

Musically naïve subjects were scanned using functional magnetic resonance imaging (fMRI) before and after they had been taught to read music and play keyboard. When subjects played melodies from musical notation after training, activation was seen in a cluster of voxels within the right superior parietal cortex consistent with the view that music reading involves spatial sensorimotor mapping.

Brain Mapping↗

Autism, Asperger syndrome and brain mechanisms for the attribution of mental states to animated shapes.

Ten able adults with autism or Asperger syndrome and 10 normal volunteers were PET scanned while watching animated sequences. The animations depicted two triangles moving about on a screen in three different conditions: moving randomly, moving in a goal-directed fashion (chasing, fighting), and moving interactively with implied intentions (coaxing, tricking). The last condition frequently elicited descriptions in terms of mental states that viewers attributed to the triangles (mentalizing). The autism group gave fewer and less accurate descriptions of these latter animations, but equally accurate descriptions of the other animations compared with controls. While viewing animations that elicited mentalizing, in contrast to randomly moving shapes, the normal group showed increased activation in a previously identified mentalizing network (medial prefrontal cortex, superior temporal sulcus at the temporo-parietal junction and temporal poles). The autism group showed less activation than the normal group in all these regions. However, one additional region, extrastriate cortex, which was highly active when watching animations that elicited mentalizing, showed the same amount of increased activation in both groups. In the autism group this extrastriate region showed reduced functional connectivity with the superior temporal sulcus at the temporo-parietal junction, an area associated with the processing of biological motion as well as with mentalizing. This finding suggests a physiological cause for the mentalizing dysfunction in autism: a bottleneck in the interaction between higher order and lower order perceptual processes.

Adult↗

Evidence for an articulatory awareness deficit in adult dyslexics.

Dyslexia is widely considered to be associated with impaired performance on phonological awareness tasks. However, it is likely that orthographic knowledge also influences performance on these tasks. In this study, adult dyslexics, for whom reading is no longer a major problem, were compared to a control group on a measure of articulatory awareness, a task which is not confounded with orthography. The dyslexic group showed deficits on the task in comparison to the control group. We hypothesize that information about articulatory movements for specific phonemes is less accessible to dyslexics because of a deficient phonological processing system.

Adult↗