Symptom Profile And Neural Bases A Social Abnormalities 1 Characteristics

Parenting Children With Asperger's And High-functioning Autism

Books on Autism

Get Instant Access

When Leo Kanner was deciding on a name that might most aptly characterize his original 11 cases, he chose the term autism, derived from the Greek work "autos" or self. His choice likely emerged from the strong sense of a preference for isolation, or the self, to the company of others observed in all his cases.

Indicators of social abnormalities are noted early in autism, quite often as early as the first few months of life. Parents often remark that as infants, their autistic children stiffened when held, failed to make prolonged eye contact, and did not cry for help or consolation. A robust early indicator of social abnormality is a near absence of joint attention, or the coordination of attention between object and person, a skill that emerges in normal infants toward the end of the first year of life. As a category, joint attention behaviors may include pointing and showing objects and the use of eye contact and direction of visual gaze to and from an object and person. Normal infants and toddlers use such gestures regularly. Autistic infants and toddlers, on the other hand, rarely use such gestures and, given that joint attention is considered a precursor to normal language development, it is not surprising that this deficit compounds into not only later deficits in social behavior but also severe deficits in language development.

As the autistic infant matures, social abnormalities become even more apparent and include decreased rates of eye contact, difficulties in expressing and identifying emotion, lack of social initiations, lack of maintaining interactions with others, and lack of an ability to demonstrate empathy. Early studies of social abnormality in autism were largely quantitative: Children with autism were shown to initiate interactions, play with peers, make eye contact, or maintain prolonged interactions with others less than normal children. Current investigations of social behavior have not only refined and brought greater detail to our understanding of the nuances involved in social dysfunction in autism but also aim to test psychological theories or hypotheses about the role that such abnormalities might play in the course of the disorder.

One such example comes from the idea that individuals with this disorder either lack or have an underdeveloped "theory of mind'' (TOM), or an inability to develop mental representations for the contents of other people's minds. By age 4, normal children can typically correctly perform simple TOM tasks, whereas most autistic individuals, with mental ages at or above 4 years, cannot, suggesting that this deficit may not be due solely to general developmental delay. Social intelligence, or TOM, comprises our ability to interpret others' mental states (thoughts, desires, beliefs, and intentions), to use this information to interact in groups, to empathize, and to predict others' thoughts and behaviors. The TOM hypothesis of autism, posited by Simon Baron-Cohen, speculates that not only is this deficit central to the symptomatology of autism and may explain social, communicative, and imaginative abnormalities but also it may be independent from general intelligence.

2. Brain-Behavior Findings

Social dysfunction in autism is severe and persistent and likely involves abnormalities in multiple neural regions, including those involved in face perception, emotion processing, orienting to social cues, and attention regulation. New functional neuroimaging studies provide the first evidence that one brain region traditionally involved in face perception (i.e., fusiform gyrus), an important constituent of social behavior, may have abnormally reduced levels of functional activation in autism (Fig. 1). Furthermore, it appears that activation to faces may instead aberrantly occur in neighboring regions or atypical locations within the fusiform gyrus; the reason for such functional relocation is unclear. One possibility is that limited exposure to faces in patients with autism (perhaps due to innate preference, biases of processing style, or learning) results in an underdevelopment or maldevelopment of face processing systems. Interestingly, recent research has reported increased fusiform gyrus activation after normal subjects were trained to be experts in identifying a novel set of nonsense objects, suggesting that the fusiform gyrus may be an area involved in the processing of extremely familiar objects or objects associated with a particular area of expertise, such as faces. In autism, limited social interactions, and eye contact in particular, could then explain decreased rates of fusiform activation. If so, early intervention strategies could be developed to help autistic toddlers and children acquire the necessary "expertise" for more normal utilization of this cortical region.

The amygdala is necessary to recognize the emotion of fear and blends of emotions, information critical to engaging in successful social interchanges. Anatomic abnormality (increased neuron density) of the amygdala has been described by one research group in nine postmortem autism cases, and two in vivo MRI studies have reported reduced amygdala volume in a small sample of adolescent patients. Although not conclusive, such initial evidence of structural defect in the amygdala sets the stage for future anatomic research and functional neuroimaging studies aimed at confirming and further elaborating its role in emotional processing deficits in autism.

Anatomic and functional defects in a third structure, the cerebellum, may contribute to deficits in orienting to social cues and regulating attention during rapid social interchanges when the source of critical social, emotional, and linguistic information shifts. Studies of autistic children show that they orient more slowly than normal to social as well as nonsocial stimuli and that the greater the impairment, the greater the cerebellar anatomical abnormality as measured by MRI. fMRI and ERP studies also show that the cerebellum plays a role in the rapidly shifting attention between different sources of sensory information and that, like patients with acquired cerebellar lesions from stroke or tumor, autistic children and adults are slow to shift attention and miss information as a consequence. Moreover, autistic patients, as well as patients with acquired cerebellar lesions, are missing at least two neurophysiological responses associated with redirecting attention—one that signals frontal cortex to orient (Fig. 2) and another that may signal posterior cortical structures to disengage and redirect attention to a new spatial locus or sensory modality.

An important caveat to both current and future fMRI research on social abnormalities in autism is that individuals with autism have less social experience than their normal peers, thus making claims about the functioning of neural regions difficult to interpret. Furthermore, tests of social intelligence frequently have complex attentional demands, yet another area of considerable difficulty for individuals with autism. Nonetheless, because social functions are markedly maldeveloped in autism, brain-behavior studies of this

Figure 1 Within group t-maps for both autism and normal groups showing significant regions of activation. Note fusiform, superior temporal sulcus and amygdala activation in normals, in comparison to a lack of positive activation in the autism group. Decreased functional activity in the autism group is likely due to the inconsistent patterns of activation noted across individual autism subjects, which would fail to be seen when results are averaged (from Pierce et al., 2001). (See color insert).

Figure 1 Within group t-maps for both autism and normal groups showing significant regions of activation. Note fusiform, superior temporal sulcus and amygdala activation in normals, in comparison to a lack of positive activation in the autism group. Decreased functional activity in the autism group is likely due to the inconsistent patterns of activation noted across individual autism subjects, which would fail to be seen when results are averaged (from Pierce et al., 2001). (See color insert).

disorder promise to provide special insights into the neural systems underlying human social development.

Was this article helpful?

0 0
Aspergers Answers Revealed

Aspergers Answers Revealed

Learn How to Help, Understand amp Cope with your Aspergers Child from a UK Chartered Educational Psychologist. Before beginning any practice relating to Aspergers it is highly recommended that you first obtain the consent and advice of a qualified health,education or social care professional.

Get My Free Ebook


Post a comment