The effect of autonomic arousal on attentional focus.

This study investigates the effect of arousal on visual selection processes. Arousal is predicted to narrow the window of attention surrounding a point of focus. BOLD response to a letter discrimination task was measured under aroused (aversive noise) and non-aroused conditions (n = 8). Results revealed spatially distinct responses for trials invoking a narrow versus wide attentional focus. Under arousal a wide focus showed posterior thalamic activation similar to that associated with the narrowed attentional focus. This reflects altered stimulus filtering and supported the hypothesis. Relevant neuroanatomy involving the locus coeruleus and a triangular circuit of selective attention is discussed. The data demonstrates the intersection of arousal and visual stimulus selection systems, identifies a cognitive consequence of arousal, and provides the first fMRI evidence for brain stem autonomic arousal.