Cognitive deficits, such as impairments of WM and attention are associated with reduced social functioning and poor outcome in schizophrenia but it is unknown how they cascade into abnormal social behavior. Schizophrenic patients have a wide range of socio-affective deficits including abnormal emotion recognition, social cue perception, “theory-of-mind” (TOM) and attribution styles but the origins of these deficits and their neural underpinnings are not yet clearly understood. We are studying the relationship between socio-affective and cognitive functions in schizophrenia using behavioral and functional neuroimaging methods.
Successful social interactions depend on fast and accurate interpretation of actions, intentions and emotions of others. We hypothesized that deficits in attentional orienting and WM may be responsible for abnormal perception and interpretation of social stimuli in schizophrenia. The neural network that supports attention and WM largely overlap with regions that are heavily implicated in the pathophysiology of schizophrenia, including the prefrontal, the posterior parietal, the anterior cingulate cortices and basal ganglia. Abnormalities of this network also result in social/affective deficits.
Cognitive roots of social deficits in schizophrenia may be characterized by: (a) inability to attend to socially or emotionally relevant features, (b) inability to generate internal representation to guide behavior, (c) inability to maintain social/emotional context in WM.
To elucidate generation of internal representation of the social world, we are examining a wide range of imitation abilities in relation to social functioning. Schizophrenic patients seem unable to imitate very simple manual gestures, mouth movements or facial expressions even thought they can correctly identify these acts. Imitation ability is related to simulation of acts and therefore whether internal representation is intact or not. Imitation ability is linked to the “mirror neuron” mechanism supported by the left inferior frontal region that includes Broca’s area. We are currently conducting a near infrared optical imaging study of language and imitation in healthy and schizophrenic subjects to relate behavior, structural findings and functional activation patterns.
To summarize, this project will enable us to understand how core cognitive deficits may lead to social deficits and contribute towards specifying the functional neuroanatomy of social cognition in schizophrenia.