Blunted EEG neural responses to emotional stimuli in schizophrenia and first degree family members

Background: Schizophrenia (SCZ) is associated with changes in both attention and social-emotional processing. While a number of studies have explored the neuroanatomy and neurophysiology (timing) of aberrant emotional processing in schizophrenia, less is known about the neural circuitry of emotional processing when the stimuli are task-irrelevant, and even less is known about emotional information processing in non-symptomatic first-degree family members. We previously reported on abnormal neural activity in frontolimbic circuits in recent-onset schizophrenia patients and first-degree relatives in an emotional oddball FMRI paradigm when processing emotionally significant but task-irrelevant stimuli. The current event-related potential study examined motivated attention to task-irrelevant emotional stimuli in recentyonset schizophrenia, first degree family member, and control subjects with an emotional visual P300 oddball detection task. Methods: Thirty schizophrenia patients with recent-onset ( <5 years), 22 first degree relatives, and 52 age, gender and parental SES matched control subjects viewed images of rare target (animal images), rare emotional (negative) and neutral (valence) pictures, and frequent "scrambled" images matched for contrast and luminance. Subjects performed a choice RT task and were instructed to press a button to the rare targets and another button to all other stimuli. We evaluated the N1, P1, N2, P3, to targets and additionally Early Posterior Negativity (EPN) and Late Positive Potential (LPP) emotional pictures. EEG acquisition was conducted form 32 channels using Neuroscan and analyzed using Edit and Matlab scripts. Results: The results revealed significant blunting of the N2, P3 to emotional stimuli in patients with schizophrenia (p