Jeffrey S. Bedwell - US grants

One the deepest mysteries of life is consciousness. Most people take for granted the fact that they are aware, that their waking experiences are framed by the construct of a "self" identity that remains consistent throughout life. But what are the physical, psychological, and cultural bases of consciousness? Some researchers believe that this construct is ultimately subjective, which means that it cannot be directly observed or measured. Some believe that consciousness can nonetheless be studied by indirect observation, while others have argued that the quality of subjective experience can never be studied by the scientific method.

With support of the National Science Foundation, Drs. Jack, Gallagher, and Raichle will join an international team of psychologists, psychiatrists, philosophers, and neuroscientists to investigate the empirical bases of consciousness. They will examine whether evidence for different conceptualizations of the self can be found in patterns of brain activity, and if so, whether their neuroscientific findings can help to further refine and expand our understanding of consciousness. Their work is focused on how the representation of self differs as a function of social and environmental contexts.

DESCRIPTION (provided by applicant): Schizophrenia is a chronic, severe, mental illness, with over 2.5 million individuals estimated to have this disorder in the United States alone. Schizophrenia has been associated with a large number of neurocognitive deficits that researchers have investigated to better understand the underlying etiology and subtypes. One deficit that has received considerable attention is dysfunction in early visual processing, which has been assessed with visual-evoked potentials (VEPs) using electroencephalography. Most VEP studies have suggested a hypoactive magnocellular (M) visual pathway in individuals with schizophrenia, while a smaller number of studies have suggested that the parvocellular (P) pathway may also be hypoactive. A separate line of investigation has demonstrated that a subset of individuals with schizophrenia show an abnormal change in visual processing to red light. Despite the existing research on these visual processing abnormalities in schizophrenia samples, they remain poorly understood in terms of related symptom profiles and neurobiological etiologies. To address this need, the proposed 3-year project will assess 100 individuals with a broad range of schizophrenia-related disorders and 100 controls. The study will use a comprehensive diagnostic and symptom assessment (both self-reported and clinician administered) along with a VEP task to examine the relationship of the early visual processing abnormalities with clusters of schizophrenia-related symptoms. We expect that the VEP-to-symptom relationships will be stronger when examined across the diagnostic boundaries of the schizophrenia-related disorders rather than within particular diagnoses. VEPs will be elicited using a repeated transient (60 ms) presentation of a checkered pattern (presented at either high or low contrast) on alternating green and red backgrounds. We will examine whether there are specific differential clusters of schizophrenia-related symptoms that relate to VEP abnormalities of interest (which includes the abnormal change to red light). In addition, we will examine how each VEP abnormality relates to visual and auditory working memory performance. The results from this study will have strong potential to increase our understanding the underlying neuropathology and etiology of the schizophrenias that likely underlie our unitary concept of schizophrenia. This could potentially uncover new clinically-meaningful diagnostic categories, thereby facilitating the search for more effective pharmacological interventions for this devastating condition. Early identification of these deficits could also set the stage for intervention or prevention programs to ameliorate the most impairing aspects of this disorder.