Seminars

The responses of neurons in primary auditory cortex (AI) depend on the summation of excitatory (E) and inhibitory (I) synaptic inputs. How the E and I inputs scale with stimulus depends on the network architecture, broadly classified either as the lateral inhibitory network (LIN) where the E inputs are more narrowly tuned than the I inputs, or the co-tuned network (CON) where the both are tuned equally. The underlying circuitry that gives rise to the CON and LIN is yet unclear. We use a combination of experiments and computer simulations to show that the same E-I network gives rise to both. By changing the spatial extent of the input to the network, we show that the spatial extent of the input determined the configuration: LIN when the input was narrow and CON when broad. Coexistence of both configurations permits multiple operational modes, enabling the auditory cortex to process a wide range of stimuli under a variety of conditions.