A Local Circuit Integration Approach to Understanding Visual Cortical Receptive Fields

The traditional concept of the receptive eld (e.g., [4, 6]) holds that each portion of the receptive eld (RF), in response to a stimulus element, has unitary (excitatory or inhibitory) in uence on neuronal response. Here, we argue: i) receptive eld components naturally have dual or vector (both excitatory and inhibitory) in uence; ii) neuronal integration is better understood in terms of local cortical circuitry than single neurons. Using a large-scale model of primary visual cortex, we demonstrate that the net e ect of a given stimulus element within either the classical or extraclassical RF can switch between excitatory and inhibitory as global stimulus conditions change. We analyze and explain these e ects by constructing self-contained modules (via a novel technique) which capture local circuit interactions. These modules illustrate a new vector-based RF analysis which uni es notions of classical and extraclassical RF, treating long-range intracortical inputs on equal footing with thalamocortical inputs.