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, Òtheory-of-mindÓ (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 Òmirror neuronÓ mechanism supported by the left inferior frontal region
that includes BrocaÕs 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.