Social Communication2

Neural Correlates

Studies have been conducted to identify the common neural basis of social decision making. One study examined the neural basis of social decision making during judgments of approachability and intelligence from faces. In the approachability task participants had to decide whether faces appeared 'not approachable or 'very approachable'. Both ASD and schizophrenic patients have shown impairment in these two tasks. In the intelligence task participants had to decide whether the faces appeared 'intelligent' or 'not intelligent'. They found that the common brain regions activated during tasks which measured these constructs included the amygdala, medial prefrontal cortex, inferior prefrontal cortex, and cerebellum. This study suggests that these structures are involved in broader social judgements as well as the specific social functions they have been associated with, such as the detection of threats by the amygdala. This study was particularly surprising because the amygdala was involved in a task in detection of intelligence. This supports the idea that the amygdala is generally involved in inferring the states of others.⁸

Impairment in pragmatic language, the ability to use and comprehend language in context, is seen universally across individuals with ASD regardless of level of functioning. Individuals with ASD employ an overly literal interpretation of utterances, causing problems in understanding humor, irony, metaphors, and comprehending indirect requests. Given that the left inferior frontal gyrus (LIFG) is particularly associated with integration of knowledge about the world and contextual information, a study investigated LIFG activation in high functioning adults that met criteria for ASD versus controls. The study targeted pragmatic language comprehension that is relevant for social interactions in daily life, specifically, the integration of speaker characteristics: age, gender, and social background. The fMRI study measured this activation for pragmatic language comprehension using speaker-congruent and speaker-incongruent sentences. Bilateral activation in the inferior frontal gyrus was found in both groups, and there was significant increased activation of the RIFG in the ASD group for speaker-incongruent sentences as opposed to speaker-congruent sentences. Increased activation in the LIFG for speaker-incongruent sentences supports the idea of the LIFG being involved in the unification of conflicting incoming information.The increased neural activity in the right inferior frontal gyrus seen in adults with ASD is suggested to be compensatory in nature. The increased activity of the RIFG in the ASD group, points to greater effort in forming and revising the situation model.⁶

vMPFC and its possible role in Autism: In one study, the right ventral MPFC showed decreased activation, but not a true deactivation, to speaker-incongruent sentences relative to speaker-congruent sentences in controls, but not adults with ASD. Furthermore, manipulating the congruency of the speaker characteristics altered activity in the right ventral MPFC, including anterior cingulated cortex.⁶ The vMPFC, including the ACC may be implicated in fundamental aspects of social cognitive functioning, such as mentalizing and theory of mind, person perception, and self-reference. The ventral part of the MPFC, including the ACC seems to be particularly associated in both self-referential judgments and inferences about perceived similarity of others to oneself.

Reward Systems in ASD

One fMRI study found decreased neural activation in the striatal reward systems in those with autism associated with abnormal social reward processing. The lack of reward from social stimuli is consistent with the hypothesis of impaired social reward processing in individuals with ASD, and potentially explains the impairments in social communication observed in those with ASD due to lack of social motivation. ⁷

Superior temporal sulcus in ASD

The STS is central for social perception (processing socially-relevant sensory information). The STS shows selective sensitivity to vocal and speech stimuli over nonsocial auditory stimuli. The STS also helps us differentiate between different voices. It is useful for relating human movements to emotional expression, eye gaze, and intentional inference. Studies suggest that individuals with ASD have both structural and functional abnormalities in the STS. ASD asults have diferences in grey matter volumes in the frontal and temporal regions, and STS grey matter is reduced bilaterally with decreased white matter concentrations in the temporal lobe and a shift in location of the STS. ASD individuals displya a cortical thinning of the STS which correlates with social and communication impairments. Additionally, there seems to be decreased connectivity between the occipital lobe and the STS, which may mean that visual information might be processed differently.¹⁰

Fusiform Gyrus

The lateral side of the mid-fusiform gyrus has been shown to selectively respond to human faces. Those with ASD have altered fusiform gyrus with reduced grey matter density, increased grey matter volume, and reduced numbers of neurons(particularly in the right half).White matter pathways to the amygdala and hippocampus are abnormal in microstructure. ¹⁰ Research suggests that unlike other areas activated by faces (amygdala, STS), the fusiform gyrus automatically responds to faces¹¹. the FFA then may be critical in recognizing people and correctly identifying the emotional expressions of others. ¹² Reduced FFA activation in working memory tasks using faces, emotion processing, and judgments of worthiness may reflect an actual difference between ASD and typically developing groups because FFA deficits are still there even after accounting for the effects of diminished attention of the eyes.¹³

Amygdala

The Amygdala is involed with facial processing, identification of emtion, perspective taking, social judgments, empathy, and threat detection. A damaged amydala results in less direct eye contact and impaired recognition of basic emotions (happiness, anger, etc) and social emotions (guilt, admiration, etc).¹⁰ There is reduced connectivity in white matter pathways with other brain regions. Poorer connectivity with the fusiform gyrus predicts ASD symptom severity. The altered amygdala might affect social communication because the amygdala plays a critical part in assigning emotional significance to stimuli. As a result, those with ASD may have an impaired ability to use emotional information to guide social behavior.¹⁰

Prefrontal Cortex

The ventromedial PFC (vmPFC) participates in motivation, reward, emotional processing, evaluation of ongoing behavior, and planning for the future. The vmPFC is connected to other limbic structures (amygdala, hippocampus). It is activated by tasks requiring empathy, theory of mind, and emotional discrimination. Those with ASD display altered patterns of vmPFC activation during these tasks. A SPECT study found that ASD children had diminished resting cerebral blood flow to the medial PFC and anterior cingulate gyrus. There was a negative correlation between medial PFC blood flow and social and communicative impairments.¹⁴ There are reductions in white matter, overall volume, and resting metabolic rates in the anterior cingulate cortex in the PFC. The ACC could be important in social interaction because glucose metabolism in the left ACC predictions social symptoms, verbal, and nonverbal communication.¹⁰

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Concerns

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References

See Citations_Social_Com2

Related Information

• Indicators (dependent variables, conditions, or contrasts; measurement variables used for analysis) associated with this construct (vote or nominate by editing this page):

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• CNP Level (What's this?)
  • Cognitive Concept

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