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A neural circuit for spatial summation in visual cortex

2012; Nature Portfolio; Volume: 490; Issue: 7419 Linguagem: Inglês

10.1038/nature11526

1476-4687

Hillel Adesnik, William Bruns, Hiroki Taniguchi, Z. Josh Huang, Massimo Scanziani,

Neuroscience and Neuropharmacology Research

The response of cortical neurons to a sensory stimulus is modulated by the context. In the visual cortex, for example, stimulation of a pyramidal cell's receptive-field surround can attenuate the cell’s response to a stimulus in the centre of its receptive field, a phenomenon called surround suppression. Whether cortical circuits contribute to surround suppression or whether the phenomenon is entirely relayed from earlier stages of visual processing is debated. Here we show that, in contrast to pyramidal cells, the response of somatostatin-expressing inhibitory neurons (SOMs) in the superficial layers of the mouse visual cortex increases with stimulation of the receptive-field surround. This difference results from the preferential excitation of SOMs by horizontal cortical axons. By perturbing the activity of SOMs, we show that these neurons contribute to pyramidal cells' surround suppression. These results establish a cortical circuit for surround suppression and attribute a particular function to a genetically defined type of inhibitory neuron. The activity of somatostatin-expressing inhibitory neurons (SOMs) in the superficial layers of the mouse visual cortex increases with stimulation of the receptive-field surround, thereby contributing to the surround suppression of pyramidal cells. The neurons of the primary visual cortex respond preferentially to stimuli of particular spatial size and are suppressed when stimuli are larger than their receptive fields. This form of modulation of neural response by contextual information is thought to underlie many perceptual phenomena, but the source of the suppression is not well understood. These authors report the identification of a circuit in the mouse visual cortex that contributes to surround suppression through a mechanism involving somatostatin-expressing interneurons.