some systems the excitation-inhibition ratio can contribute to shaping the response of a cortical neuron to distinct stimuli. As a consequence, because neighboring principal neurons in several cortical sensory areas are not necessarily tuned to the same stimuli (i.e. the rodent visual cortex with regard to orientation (Ohki et al., 2005); the auditory cortex with regard to frequency (Bandyopadhyay et al., 2010; Rothschild et al., 2010) and the olfactory cortex with regard to odors (Stettler and Axel, 2009) in response to a given stimulus, the ratio between excitation and inhibition may vary significantly between nearby neurons. Thus, differences in the excitation-inhibition ratio between neurons can also shape the activity pattern of a population of cortical neurons in space.
