Fig. 6.

Comparison of response magnitudes of individual neurons in the D2 barrel column to stimulation of D1 and D3 whiskers in normal animals (i.e., whiskers not trimmed) (A), diet control animals after 7 d of whisker pairing (D1 and D2 were paired) (B), and PAE animals after 7 d of whisker pairing (D1 and D2 were paired) (C). Theleft column (Sort by Cell) of each pair of bars represents the response of each neuron to stimuli to the D1 (striped bars) and D3 (black bars) whiskers, and they are sorted arbitrarily in descending order by the magnitude of D1 responses to illustrate how each neuron varied in its response. Neurons in all layers and with all spike durations were included in the sample. In the right column of each pair (Sort by Mag), the neurons were sorted independently by the magnitude of response to D1 and D3. Thus, the Sort by Mag. column no longer represents the responses of single neurons, but this procedure greatly enhances visualization of the symmetry or asymmetry of the responses of the two surround whiskers before and after whisker pairing in the entire sample of neurons. The numbers for each pair of columns indicate the percentage of neurons that responded better to one or the other whisker. The PAE animals showed no significant shift toward the intact D1 surround whisker after 7 d. The width of the individual bars was determined by the number of neurons in the sample displayed in a column of fixed length. The magnitude of response was truncated above 50 spikes/50 stimuli. Theopen arrow points to a neuron that responded best to D1 whisker, and the closed arrow points to a neuron with stronger response to D3 whisker in the normal animal. The triple arrow points to three neurons that still had better responses to the cut D3 whisker in control animals after 7 d of whisker pairing. The x-axis is the response level in spikes/50 stimuli for the D1 and D3 whisker.