The neurophysiology of biological motion perception in schizophrenia.
BACKGROUND
The ability to recognize human biological motion is a fundamental aspect of social cognition that is impaired in people with schizophrenia. However, little is known about the neural substrates of impaired biological motion perception in schizophrenia. In the current study, we assessed event-related potentials (ERPs) to human and nonhuman movement in schizophrenia.


METHODS
Twenty-four subjects with schizophrenia and 18 healthy controls completed a biological motion task while their electroencephalography (EEG) was simultaneously recorded. Subjects watched clips of point-light animations containing 100%, 85%, or 70% biological motion, and were asked to decide whether the clip resembled human or nonhuman movement. Three ERPs were examined: P1, N1, and the late positive potential (LPP).


RESULTS
Behaviorally, schizophrenia subjects identified significantly fewer stimuli as human movement compared to healthy controls in the 100% and 85% conditions. At the neural level, P1 was reduced in the schizophrenia group but did not differ among conditions in either group. There were no group differences in N1 but both groups had the largest N1 in the 70% condition. There was a condition × group interaction for the LPP: Healthy controls had a larger LPP to 100% versus 85% and 70% biological motion; there was no difference among conditions in schizophrenia subjects.


CONCLUSIONS
Consistent with previous findings, schizophrenia subjects were impaired in their ability to recognize biological motion. The EEG results showed that biological motion did not influence the earliest stage of visual processing (P1). Although schizophrenia subjects showed the same pattern of N1 results relative to healthy controls, they were impaired at a later stage (LPP), reflecting a dysfunction in the identification of human form in biological versus nonbiological motion stimuli.
Mental Illness Research, Education and Clinical Center (MIRECC), VA Greater Los Angeles Healthcare System Los Angeles, California ; Semel Institute for Neuroscience and Human Behavior, University of California Los Angeles, California.
Carol
C
Jahshan
Mental Illness Research, Education and Clinical Center (MIRECC), VA Greater Los Angeles Healthcare System Los Angeles, California ; Semel Institute for Neuroscience and Human Behavior, University of California Los Angeles, California.
Jonathan K
JK
Wynn
Mental Illness Research, Education and Clinical Center (MIRECC), VA Greater Los Angeles Healthcare System Los Angeles, California ; Semel Institute for Neuroscience and Human Behavior, University of California Los Angeles, California.
Kristopher I
KI
Mathis
Mental Illness Research, Education and Clinical Center (MIRECC), VA Greater Los Angeles Healthcare System Los Angeles, California ; Semel Institute for Neuroscience and Human Behavior, University of California Los Angeles, California.
Michael F
MF
Green
D000293:Adolescent; D000328:Adult; D016022:Case-Control Studies; D004569:Electroencephalography; D005071:Evoked Potentials; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009039:Motion Perception; D012559:Schizophrenia / Q000503:physiopathology*; D013997:Time Factors; D055815:Young Adult
Biological motion; electroencephalography; event-related potential; schizophrenia; visual perception