Heterogeneity in the Coding in Rat Barrel Cortex of the Velocity of Protraction of the Macrovibrissae.
From: Department of Physiology, Monash University, Clayton, Victoria 3800, Australia. ramesh.rajan@med.monash.edu.au
The European journal of neuroscience
- Publish Date: Apr 2007
- ISSN: 0953-816X
- Volume: 25
- Issue: 8
- Pages: 2383-403
- Medium: Print
- Language: English
- Citation (JAMA): Rajan R, Browning Andrew S, Bourke Justin L, et al. Heterogeneity in the Coding in Rat Barrel Cortex of the Velocity of Protraction of the Macrovibrissae.. Eur. J. Neurosci. Apr 2007;25:2383-403
Abstract
Rats whisk to explore their environment and obtain information on object features, and the responses of somatosensory cortical neurones must precisely encode aspects of whisker movements. Using trapezoidal stimuli to deflect whiskers, with a wide range of velocities and amplitudes of whisker protraction, we recorded responses from a relatively homogeneous population of isolated cells and neuronal multiunits within the postero-medial barrel sub-field of somatosensory cortex, and analysed responses in an early post-stimulus-onset window. For 92% of neurones the function relating response strength to velocity was a saturating sigmoid but there were differences between neurones in the slopes and ranges over which responses changed. Responses of other neurones were non-monotonic, with response strength decaying at very high whisker deflection velocities. Generally, barrel cortex neurones were responsive to a much wider range of whisker protraction velocities than hitherto reported, especially to much slower velocities than generally assumed to be the main range of sensitivity. This carries implications for coding of whisker deflection velocity, a parameter that appears to be a significant information-bearing element of natural whisking. The effect of amplitude of deflection upon neural responses was evident in only approximately 24% of units and only when the dominant velocity effect had saturated.
Mesh Headings (Keywords): Animals, Behavior, Animal, Brain Mapping, Electrophysiology, Evoked Potentials, Neurons, Rats, Rats, Sprague-Dawley, Regression Analysis, Somatosensory Cortex, Vibrissae
Check for Full Text / PubMed Unique Identifier (PMID): 17445236
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