Spatiotemporal receptive fields of barrel cortex revealed by reverse correlation of synaptic input

• Published in: Nature neuroscience Vol. 17; no. 6; pp. 866 - 875
• Main Authors: Ramirez, Alejandro, Pnevmatikakis, Eftychios A, Merel, Josh, Paninski, Liam, Miller, Kenneth D, Bruno, Randy M
• Format: Journal Article
• Language: English
• Published: New York Nature Publishing Group US 01.06.2014; Nature Publishing Group
• Subjects: 14/63; 59; 631/378/116/2395; 631/378/2620/2618; 631/378/2620/2622; 631/378/2620/2623; 64/86; 9/74; Animal Genetics and Genomics; Animals; Behavioral Sciences; Biological Techniques; Biomedicine; Cerebral Cortex - physiology; Female; Neocortex; Neurobiology; Neurons; Neurons - physiology; Neurosciences; Physical Stimulation - methods; Physiological aspects; Rats; Rats, Wistar; Rodents; Somatosensory system; Synapses - physiology; Synaptic Potentials - physiology; Time Factors; Vibrissae - physiology; United States; New York; United States > US
• ISSN: 1097-6256; 1546-1726; 1546-1726
• DOI: 10.1038/nn.3720

To investigate the sensory contributions of barrel cortex, the authors estimate spatiotemporal receptive fields by reverse correlation of multi-whisker stimulation to synaptic inputs. Complex stimuli revealed dramatically sharpened receptive fields, largely due to adaptation, and suggest the potential importance of surround facilitation through adaptation for discriminating complex shapes and textures during natural sensing. Of all of the sensory areas, barrel cortex is among the best understood in terms of circuitry, yet least understood in terms of sensory function. We combined intracellular recording in rats with a multi-directional, multi-whisker stimulator system to estimate receptive fields by reverse correlation of stimuli to synaptic inputs. Spatiotemporal receptive fields were identified orders of magnitude faster than by conventional spike-based approaches, even for neurons with little spiking activity. Given a suitable stimulus representation, a linear model captured the stimulus-response relationship for all neurons with high accuracy. In contrast with conventional single-whisker stimuli, complex stimuli revealed markedly sharpened receptive fields, largely as a result of adaptation. This phenomenon allowed the surround to facilitate rather than to suppress responses to the principal whisker. Optimized stimuli enhanced firing in layers 4–6, but not in layers 2/3, which remained sparsely active. Surround facilitation through adaptation may be required for discriminating complex shapes and textures during natural sensing.