Corticospinal Excitability During a Perspective Taking Task:

1. TMS Pulse MEP 1PP 3PP How many balls do you see? How many balls does the avatar see? How many balls do you see? How many balls does the avatar see? How many balls do you see? How many balls does the avatar see? How many balls do you see? How many balls does the avatar see? Corticospinal Excitability During a Perspective Taking Task: Implications for Self vs. Other Brain Processing Elizabeth Murray1, Karen Kelly1, Alexander Shepard2, Kandy Bandahar3, Julian Paul Keenan1 1cognitive neuroimaging laboratory, montclair state university, 2university of pennsylvania, 3new york university results introduction • For each condition, measures of TMS-induced MEPs for filtered and rectified, grand-averaged data were analyzed in terms of area under the curve (AUC) and peak amplitude using repeated measures Analysis of Variance (ANOVAs). • FOR PEAK AMPLITUDE: • A significant main effect for self/other was found F = 5.57, p < .05. A significant interaction between hemisphere x condition was also found F= 6.55, p < .05. • FOR AREA UNDER THE CURVE: • A significant main effect was found for hemisphere F= 6.66, p < .05 and for the self/other condition F= 8.029, p < .05. A significant interaction between hemisphere and self/other condition was found F= 11.63, p < .05. One of the most fascinating and widely studied areas in psychology, philosophy, and neuroscience is consciousness. Due to the complex and multifaceted nature of consciousness, it is common for a particular aspect to be studied independently, making controlled experimental manipulation possible. One aspect of particular interest is the uniquely human ability to take not only a self-perspective but the ability to take another’s mental viewpoint, or other- perspective. This ability to take the first person perspective (1PP) and third person perspective (3PP) is a necessary component of human self consciousness (Vogeley & Fink, 2003) as well as a necessary component of both self-awareness (SA) and Theory of Mind (ToM). The 1PP plays a valuable role during social cognition in terms of the benefit of self-analysis and modification however, its mediating role in taking the 3PP may be even more valuable. In order to take the 3PP, one must first be aware of the self; without self-awareness, other-awareness is not possible. Having the ability to take the 3PP enables humans to cognitively speculate others’ mental states and intentions (mental state-attribution or ToM). The neural activation during 1PP vs. 3PP is of particular interest especially in terms of deficiencies in self/other processing (i.e. autism, schizophrenia, etc.) as well as, an insights into the neuroevolution of cognitive function. Although several neuroimaging studies have attempted to provide a “neural signature” of these states, the common and differential neural substrates involved, remain elusive. Area Under the Curve methods • Ten adults participants were recruited and appropriately screened using TMS safety guidelines established by Wasserman (1996, 1998). • Using a paradigm designed by Vogley et al. (2004), subjects were asked to take either the first-person perspective (1PP) or third person perspective (3PP) in identifying the number of red balls in a virtual scene. • Single-pulse Transcranial Magnetic Stimulation (TMS) was administered to the motor cortex of either the left or right hemisphere 150msec or 300msec following stimulus presentation. All stimulation was delivered at 100% MT. • Motor-evoked potentials (MEPs) were recorded using three surface electrodes attached to the hand, contralateral to the hemisphere stimulated, at the abductor pollicus brevis (APB) and the belly-tendon montage. discussion The results suggest that taking the self perspective is the default perspective and that the right hemisphere may be highly specialized for this default state, the self perspective The data support past research indicating right hemisphere advantage for self-related processing. Future studies may investigate information transfer between intra-hemisphere structures during decisions requiring taking first and/or third person perspective to further study the co-evolution of these processes. Results from this study, will further elucidate the neural pathways involved during perspective taking and facilitate the understanding of psychopathological syndromes in which there are functional deficits of self-awareness and theory of mind as well as, the neurophysiology of social cognitive brain processes which rely on such perspective taking Peak Amplitude Average MEPs For All Conditions www.cogneurolab.com