Multisensory responses in primary auditory cortex of the cat
Abstract
Core auditory cortex of the cat is comprised of primary auditory cortex (A1) and the anterior auditory field (AAF). Neurons in both fields respond strongly to acoustic stimuli and are tonotopically organized. In hearing animals, a small number of cells in AAF respond to tactile stimulation. However, it is unclear if multisensory input influences responses in A1. In this study, multisensory stimuli were developed by pairing a pure tone stimulus with a flash stimulus at various stimulus onset asynchronies. A linear multielectrode array recorded multi-unit activity in A1 across cortical layers. We identified unisensory auditory, unisensory visual, bimodal, and subthreshold multisensory multi-unit activity. We also found neurons where auditory-visual interactions either suppressed or enhanced neuronal activity. Additionally, visual stimulation can modulate the neural response to auditory inputs depending on the stimulus onset asynchrony. Taken together, the majority of neural activity in A1 in the cat is influenced by visual inputs.