Compensatory Plasticity in the Lateral Extrastriate Visual Cortex Preserves Audiovisual Temporal Processing following Adult-Onset Hearing Loss

Figure 2

Recording site reconstruction and audiovisual-evoked CSD analysis in the multisensory zone of the V2L cortex (V2L-Mz). (a) The schematic shows a reconstruction of all recording penetrations in normal-hearing control rats (grey; ) and noise-exposed rats (blue; ). In each rat, two penetrations were performed in the lateral extrastriate visual cortex: one in the multisensory zone of V2L (V2L-Mz) and the other in the more ventral-positioned, auditory zone of V2L (V2L-Az). (b) A representation of a 32-channel linear electrode array spanning the entire cortical thickness within V2L-Mz. (c) Representative CSD profile in a control rat in response to audiovisual stimuli presented at an SOA of 30 ms. Prominent current sinks (red) are reflective of a depolarization of neurons in the surrounding cortical region, whereas prominent current sources (blue) reflect a repolarization of neurons in the surrounding cortical regions. The black horizontal bar denotes the presentation of the visual stimulus (50 ms LED flash at 15 lux), and the grey horizontal bar shows the timing of the auditory stimulus (50 ms noise burst at 40 dB above click threshold). (d) Average rectified current source density (AVREC) analysis derived from the CSD profiles in (c) in response to the combined audiovisual stimulus.