Why can an inhibitory part of a receptive field be included in the classical receptive field?

In the context of sensory physiology, the classical receptive field is defined as the specific region in the sensory periphery where stimuli can elicit a change in a neuron's background firing rate.1

An inhibitory part of a receptive field is included in the classical receptive field because stimuli presented within these inhibitory subregions are capable of evoking a response when they are turned off. This phenomenon is a key component of centre-surround antagonism, where the onset of a stimulus in one region elicits an excitatory response, while the onset of a stimulus in the surrounding region elicits an inhibitory response.1

Because these inhibitory subregions directly influence the neuron's spiking activity—either by suppressing it or by triggering a response upon the stimulus's removal—they are functionally integrated into the classical receptive field. This organization allows the nervous system to perform essential processing, such as detecting local contrast, rather than simply responding to uniform stimulation.12