Eye Movement-Related Activity in and below the Macaque Auditory Cortex

Recent studies have revealed influences of viewing scenes on sound processing and of gaze direction on sound location coding in the auditory cortex of the macaque monkey. We examined the spontaneous activity of auditory cortex in the darkness. During those recordings, no sound stimuli were delivered but eye movements were recorded. We found locally-generated field potentials related to eye movements in the absence of sensory stimuli. Spectral power in these field potentials was mostly concentrated in the delta-theta (∼1–8 Hz) ranges. The amplitude of field potential tends to grew larger with depth below auditory cortex, suggestive of a contribution from far field signals generated at loci below auditory cortex proper. Current source density (CSD) analyses confirmed the electrical events occurred in the superior temporal sulcus. CSD analyses also indicated the possibility that there were local electrical events related to eye movements occurring in auditory cortex