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

Figure 4

A loss of the characteristic audiovisual temporal profile was observed across the majority of layers of the multisensory zone of the V2L cortex in noise-exposed rats. Averaged CSD waveforms from the (a) supragranular, (b) granular, (c) infragranular upper, and (d) infragranular lower layers within the V2L-Mz in response to audiovisual stimuli presented at SOAs of 0, 30, and 50 ms. The black horizontal bar denotes the presentation of the visual stimulus, and the grey horizontal bar shows the timing of the auditory stimulus. The dark lines represent the group mean, and the shading represents the SEM for the noise-exposed rats (blue; ) and age-matched controls (light grey; ). An analysis of audiovisual-evoked sink amplitudes within each cortical layer (see bar graphs on the far right) shows an increase in responsiveness across most of the cortical layers in the noise-exposed rats. Values are displayed as . and .

(a) Supragranular layer

(b) Granular layer

(c) Infragranular (upper) layer

(d) Infragranular (lower) layer