Excitatory and suppressive receptive field subunits in awake monkey primary visual cortex (V1).
An essential step in understanding visual processing is to characterize the neuronal receptive fields (RFs) at each stage of the visual pathway. However, RF characterization beyond simple cells in the primary visual cortex (V1) remains a major challenge. Recent application of spike-triggered covariance (STC) analysis has greatly facilitated characterization of complex cell RFs in anesthetized animals. Here we apply STC to RF characterization in awake monkey V1. We found up to nine subunits for each cell, including one or two dominant excitatory subunits as described by the standard model, along with additional excitatory and suppressive subunits with weaker contributions. Compared with the dominant subunits, the nondominant excitatory subunits prefer similar orientations and spatial frequencies but have larger spatial envelopes. They contribute to response invariance to small changes in stimulus orientation, position, and spatial frequency. In contrast, the suppressive subunits are tuned to orientations 45 degrees -90 degrees different from the excitatory subunits, which may underlie cross-orientation suppression. Together, the excitatory and suppressive subunits form a compact description of RFs in awake monkey V1, allowing prediction of the responses to arbitrary visual stimuli.
Chen
Xiaodong
X
Institute of Neuroscience, State Key Laboratory of Neuroscience, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yue-Yang Road, Shanghai 200031, China.
Han
Feng
F
Poo
Mu-Ming
MM
Dan
Yang
Y
D000200:Action Potentials / Q000502:physiology; D000818:Animals; D005260:Female; D005403:Fixation, Ocular / Q000502:physiology; D008253:Macaca mulatta; D008297:Male; D008959:Models, Neurological; D009474:Neurons / Q000502:physiology*; D018408:Patch-Clamp Techniques; D010775:Photic Stimulation; D009435:Synaptic Transmission / Q000502:physiology; D014793:Visual Cortex / Q000166:cytology* / Q000502:physiology; D014795:Visual Pathways / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology*; D014851:Wakefulness