Temporal and spatial integration in the rat SI vibrissa cortex
TLDR
Glass micropipettes were used to record the activity of 124 single units in the somatosensory vibrissa cortex of 16 rats in response to combined deflections of contralateral vibrissae, finding that response suppression is strongest at short interdeflection intervals and decreases progressively during the 50-100 ms following the first deflection.Abstract:
Glass micropipettes were used to record the activity of 124 single units in the somatosensory vibrissa cortex (SI) of 16 rats in response to combined deflections of contralateral vibrissae. Compact multiangular electromechanical stimulators were used to stimulate individual vibrissal hairs alone or in combinations of two or three adjacent whiskers. Each whisker was stimulated independently to produce controlled temporal and spatial patterns of mechanical stimuli. Following displacement of a vibrissa, unit discharges to subsequent deflections of adjacent whiskers are reduced in a time-dependent fashion. Response suppression is strongest at short interdeflection intervals, i.e., 10-20 ms and decreases progressively during the 50-100 ms following the first deflection. In many cases this period also corresponds with a reduction in ongoing unit discharges. Response suppression was not observed for first-order neurons recorded in the trigeminal ganglion of barbiturate-anesthetized rats. In the cortex, the presence and/or degree of response suppression depends on a number of spatial factors. These include 1) the angular direction(s) in which the individual hairs are moved, 2) the sequence in which two whiskers are deflected, that is, which one is deflected first, 3) the particular combination of whiskers stimulated, and 4) the number (2 or 3) of vibrissae comprising the multiwhisker stimulus. Within a vertical electrode penetration, one particular whisker typically elicits the strongest excitatory and inhibitory effects; other, nearby vibrissae elicit variable (or no) excitation or inhibition. Excitatory and inhibitory subregions of a receptive field could thus be distributed asymmetrically around the maximally effective whisker. In these cases, the receptive fields displayed spatial orientations. Quantitative criteria were used to classify 30 cortical units on the basis of the distribution of inhibitory subregions on either side of the maximally effective whisker. Twenty-one of these cells had receptive fields (RFs) with symmetrical inhibitory side regions. Responses of the other nine units were strongly suppressed by a preceding deflection of a vibrissa on one side but relatively unaffected, or even slightly facilitated, by preceding deflection of the whisker on the other side.(ABSTRACT TRUNCATED AT 400 WORDS)read more
Citations
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Biometric analyses of vibrissal tactile discrimination in the rat
TL;DR: The capacity of the rodent whisker system to distinguish a smooth surface from a rough one is comparable to that of primates using their fingertips and suggest common strategies for active touch in the mammalian somatomotor system.
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Thalamocortical responses of mouse somatosensory (barrel) cortex in vitro.
A. Agmon,Barry W. Connors +1 more
TL;DR: The thalamo-cortical slice is a very suitable system for studying the physiology and pharmacology of the thalamocortical synapse and for exploring the synaptic circuitry of the somatosensory cortex.
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Thalamocortical response transformation in the rat vibrissa/barrel system.
TL;DR: A cyclic pattern of stimulus-evoked excitation/inhibition characterizes responses in the cortical barrels but is considerably less pronounced in the thalamic barreloids.
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Functional architecture of the mystacial vibrissae.
TL;DR: A synthesis of morphological and behavioral data led to the following functional concept: the mystacial macrovibrissae row is a distance decoder, whose function is to derive head centered obstacle/opening contours at the various dorsoventral angles represented by vibrissal rows.
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Visualizing the Cortical Representation of Whisker Touch: Voltage-Sensitive Dye Imaging in Freely Moving Mice
TL;DR: These experiments demonstrate that fiber optics can be used to image cortical sensory activity with high resolution in freely moving animals and demonstrate differential processing of sensory input depending upon behavior.
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