Autism diagnosis differentiates neurophysiological responses to faces in adults with tuberous sclerosis complex

- Background: Autism spectrum disorder (ASD) is a common and highly heritable neurodevelopmental disorder that is likely to be the outcome of complex aetiological mechanisms. One strategy to provide insight is to study ASD within tuberous sclerosis complex (TSC), a rare disorder with a high incidence of ASD, but for which the genetic cause is determined. Individuals with ASD consistently demonstrate face processing impairments, but these have not been examined in adults with TSC using event-related potentials (ERPs) that are able to capture distinct temporal stages of processing. - Methods: For adults with TSC (n = 14), 6 of which had a diagnosis of ASD, and control adults (n = 13) passively viewed upright and inverted human faces with direct or averted gaze, with concurrent EEG recording. Amplitude and latency of the P1 and N170 ERPs were measured. - Results: Individuals with TSC + ASD exhibited longer N170 latencies to faces compared to typical adults. Typical adults and adults with TSC-only exhibited longer N170 latency to inverted versus upright faces, whereas individuals with TSC + ASD did not show latency differences according to face orientation. In addition, individuals with TSC + ASD showed increased N170 latency to averted compared to direct gaze, which was not demonstrated in typical adults. A reduced lateralization was shown for the TSC + ASD groups on P1 and N170 amplitude. - Conclusions: The findings suggest that individuals with TSC + ASD may have similar electrophysiological abnormalities to idiopathic ASD and are suggestive of developmental delay. Identifying brain-based markers of ASD that are similar in TSC and idiopathic cases is likely to help elucidate the risk pathways to ASD

Recognition of complex object-centred spatial configurations in early infancy

In a series of experiments we tested 4- and 8-month-olds' ability to represent the spatial layout of an object across changes in its orientation with respect to egocentric spatial coordinates. A fixed-trial familiarisation procedure based on visual habituation behaviour shows that both age-groups are able to discriminate between different object-centred spatial configurations. Furthermore, both age-groups demonstrate the ability to make discriminations of object-centred spatial coordinates that require simultaneous reference to at least two spatial axes of the object. We discuss these findings in relation to theories of the early development of object recognition and spatial reference skills

ORIGINAL ARTICLE - Near infrared spectroscopy reveals neural activation during face perception in infants and adults

We used near infrared spectroscopy to measure changes in cerebral oxygenation in both human infants and adults as they viewed images of faces or control “visual noise” stimuli. At an occipital site, adults showed a significant increase in oxyhaemoglobin and a contrasting pattern of results was observed in infants. While the same general difference between the processing of the two stimuli was observed, a larger decrease in oxyhemoglobin concentration in response to faces than to visual noise was found in infants. These results demonstrate that near infrared spectroscopy can detect differences in stimulus processing induced by a complex visual stimulus in both infants and adults. (J Pediatr Neurol 2004; 2(2): 85-89)

Additional file 2: Tables S1–S3. of Autism diagnosis differentiates neurophysiological responses to faces in adults with tuberous sclerosis complex

Table S1: Mean (SD) number of segments in each ERP average per stimulus and group during the face and gaze processing task. Table S2: Mean (SD) amplitude (in μV) and latency (in ms) for the P1 for each stimulus by group. Table S3: Mean amplitude (in μV) and latency (in ms) for the N170 for each stimulus by group

Infants can infer the presence of hidden objects from referential gaze information

Infants' apparent failure in gaze-following tasks is often interpreted as a sign of lack of understanding the referential nature of looking. In the present study, 8- and 12-month-old infants followed the gaze of a model to one of two locations hidden from their view by occluders. When the occluders were removed, an object was revealed either at the location where the model had looked or at the other side. Infants at both ages looked longer at the empty location when it had been indicated by the model's looking behaviour, and this effect held up even when their first look after gaze following was discounted. This result demonstrates that even young infants hold referential expectations when they follow others' gaze and infer the location of hidden objects accordingly