Figure 3.

Quantitative comparison of silencing intracortical activity by GABA_A agonist muscimol alone or by applying muscimol in combination with the GABA_B receptor agonist SCH50911 to block possible side effects of muscimol on presynaptic processing of thalamocortical input (see Results). A, Mean ± SEM peak amplitudes of the granular sink S1 evoked by pure tones of different spectral distance to the best frequency. Note the significant decreases of amplitude values at the BF and nearBF frequencies and the total absence of measurable responses at nonBF frequencies (for quantification of the ratios of decrease, see Table 1) after both silencing methods. B, Mean ± SEM onset latency of granular sink S1 decreased after drug application selectively for nearBF stimulation but was constant for BF stimulation. In all cases, we did not find significant differences between muscimol (n = 10) or muscimol plus SCH50911 (n = 3) induced cortical silencing. *p < 0.001 indicates significant changes after drug application (paired t test).