1. Neuronal responses to intracortical microstimulation in V1.
Neuronal responses to intracortical microstimulation in V1. A, Example of reduction of four-element full representation of electrical stimulation vector (four-element vector where each number represents frequency of microstimulation at a different location) down to two-dimensional population vector. There are five examples from five different time points T1–T5. B, Geometric representation of the population vectors from A. C, Stimulus population vectors from all trials in a session, with mean of first and last three substimuli overlaid in red. The black diamond outline is the convex hull of stimulus population vectors, showing the perimeter of the set of all possible vectors. Note that only a fraction of this set is actually presented in a given behavioral session. See text for more details. D, Neuronal data from four representative units. PSTHs show mean response to first three and last three microstimulation pulses, averaged over all trials in the session (note there are different axis limits for the different PSTHs). Associated with each PSTH is an IR-RF, a contour plot that shows the mean number of spikes in response to each stimulus population vector, with hot colors representing high firing rates. E, Distribution of all 240 IR-RF centers from all units recorded: note they tend to concentrate at the two medial corners of the stimulus space, although these are fairly rare events (C). F, Polar count histogram illustrates the medial, rather than anterior, concentration of IR-RF angular distribution. G, H, Same as E and F, but from data from S1 from a previous study (Hartmann et al. 2016). Note the anterior distribution of the IR-RF centers, much closer to the distribution of the stimuli.
Eric E. Thomson et al. eNeuro 2017;4:ENEURO
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