Compensating Level-Dependent Frequency Representation in Auditory Cortex by Synaptic Integration of Corticocortical Input - Fig 5

<p>Temporal precision of thalamocortical and corticocortical synaptic inputs with varying stimulus intensity <b>A.</b> <i>Left</i>, Mean (±SEM) granular sink onset latency in untreated AI showed similar shift of the frequency evoking the earliest onset (2.1±0.85 oct. below CF), as compared to the FMR. Frequencies evoking the shortest onset or the maximal peak response were identical in most cases and differed maximally in one octave from the FMR (data not shown). <i>Right</i>, After silencing the corticocortical contribution of tone-evoked activity in AI the V-shaped onset-latency tuning was flattened to latencies comparable to CF stimulation in untreated cortex and reduced in bandwidth to CF- and near-CF-frequencies (cf. Happel et al., 2010). <b>B.</b> Schematic illustration of the mutually underlying cortical circuitry allowing to detect contributions to the evoked responses from the horizontal corticocortical circuitry in time (Happel et al., 2010). <b>C.</b> Before cortical silencing, negative mean (±SEM) latency difference of <i>RelResCSD onset latency–AVREC onset latencies</i> indicating temporal lead of the thalamocortical input over lateral corticocortical input was only found for BF stimulation. When stimulating with pure tones in spectral distance to the BF those differences were vanished, indicative for a temporally highly precise integration of substantial corticocortical contributions.