***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Systematic studies of infants with autism have not been previously carried out . Taking advantage of a new prospect i ve screening instrument for autism in infancy ( S. Baron-Cohen et al. , 1996 ) , the present study found that , compared with developmentally delayed and normally developing children , 20-month-old children with autism were specifically impaired on some aspects of empathy , joint attention , and imitation .  Infants with autism failed to use social gaze in the empathy and joint attention tasks . Both the infants with autism and the infants with developmental delay demonstrated functional play , but very few participants in either group produced spontaneous pretend play . In the developmental delay group , but not the autism group , pretend play was shown following prompting . The implication s of these findings for developmental accounts of autism and for the early diagnosis of the disorder are discussed Nonconscious  behavioral mimicry  occurs when a person unwittingly imitates the behaviors of another person . This mimicry has been attributed to a direct link between perceiving a behavior and performing that same behavior . The current experiments explored whether having a goal to affiliate augments the tendency to mimic the behaviors of interaction partners .  Experiment 1 demonstrated that having an affiliation goal increases nonconscious mimicry , and Experiment 2 further supported this proposition by demonstrating that people who have unsuccessfully attempted to affiliate in an interaction subsequently exhibit more mimicry than those who have not experienced such a failure . Results suggest that behavioral mimicry  may be part of a person 's repertoire of behaviors , used nonconsciously , when there is a desire to create rapport Autism spectrum disorder ( ASD ) is a neurodevelopmental disorder associated with impaired social and emotional skills , the anatomical substrate of which is still unknown . In this study , we compared a group of 14 high-functioning ASD adults with a group of controls matched for sex , age , intelligence quotient , and h and edness . We used an automated technique of analysis that accurately measures the thickness of the cerebral cortex and generates cross-subject statistics in a coordinate system based on cortical anatomy . We found local decreases of gray matter in the ASD group in areas belonging to the mirror neuron system ( MNS ) , argued to be the basis of empathic behavior . Cortical thinning of the MNS was correlated with ASD symptom severity . Cortical thinning was also observed in areas involved in emotion recognition and social cognition . These findings suggest that the social and emotional deficits characteristic of autism may reflect abnormal thinning of the MNS and the broader network of cortical areas subserving social cognition We investigated whether individuals with autism spectrum disorders ( ASD ) would show attentional modulation for social ( face ) and non-social ( house ) stimuli . Sixteen individuals with ASD and 16 matched control participants completed a task in which pairs of face and house stimuli were present on every trial , with one of the pairs r and omly assigned to attended locations and the other to unattended locations . Both mass-univariate ( SPM ) and region of interest analyses suggested that responses to houses were modulated by attention in both groups , but that only the control participants demonstrated attentional modulation of face-selective regions . Thus , the participants with ASD demonstrated a lack of attentional modulation which was particularly evident for the social stimulus . Analyses of effective connectivity indicated that these results were due to a failure of attention to modulate connectivity between extrastriate areas and V1 . We discuss how these results may suggest a mechanism to explain the reduced salience of social stimuli in ASD To examine mirror neuron abnormalities in autism , high-functioning children with autism and matched controls underwent fMRI while imitating and observing emotional expressions . Although both groups performed the tasks equally well , children with autism showed no mirror neuron activity in the inferior frontal gyrus ( pars opercularis ) . Notably , activity in this area was inversely related to symptom severity in the social domain , suggesting that a dysfunctional ' mirror neuron system ' may underlie the social deficits observed in autism 
    Output:
    
The only well localised measure of mirror system function is fMRI .
In fMRI studies , those using emotional stimuli have reported group differences , but studies using non-emotional h and action stimuli do not .
Overall , there is little evidence for a global dysfunction of the mirror system in autism .
Current data can be better understood under an alternative model in which social top-down response modulation is abnormal in autism .