A model of multiplicative neural responses in parietal cortex.
Visual responses of neurons in parietal area 7a are modulated by a combined eye and head position signal in a multiplicative manner. Neurons with multiplicative responses can act as powerful computational elements in neural networks. In the case of parietal cortex, multiplicative gain modulation appears to play a crucial role in the transformation of object locations from retinal to body-centered coordinates. It has proven difficult to uncover single-neuron mechanisms that account for neuronal multiplication. Here we show that multiplicative responses can arise in a network model through population effects. Specifically, neurons in a recurrently connected network with excitatory connections between similarly tuned neurons and inhibitory connections between differently tuned neurons can perform a product operation on additive synaptic inputs. The results suggest that parietal responses may be based on this architecture.
Salinas
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Volen Center for Complex Systems, Brandeis University, Waltham, MA 02254-9110, USA.
Abbott
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LF
D000818:Animals; D006257:Head; D006801:Humans; D008433:Mathematics; D008959:Models, Neurological; D009415:Nerve Net / Q000502:physiology*; D009474:Neurons / Q000502:physiology*; D010296:Parietal Lobe / Q000502:physiology*; D011187:Posture; D012160:Retina / Q000502:physiology*; D013569:Synapses / Q000502:physiology; D014785:Vision, Ocular; D014796:Visual Perception