Article Figures & Data
Figures
- Fig. 1.
Monophasic cortical response to single-whisker stimulation. A, Spatiotemporal dynamics of spread of averaged response (n = 128 trials) to whisker C3 stimulation using a 3 msec air puff. B, Average time course of response (SEs are displayed every five frames).C, Contour map comparing the response to whisker C3 versus C2. Note that the distance between the centers of activation in the two cases is <0.5 mm. D, The differential map of C3 and C2 activation revealing the cortical axis along rowC.E, Averaged response to E1 mechanical stimulation (10 msec; n = 244) at the center of activity and at a ring-like shape 0.9 mm away from the barrel center (frame rate, 0.6 msec/frame). The response was normalized to maximum. Inset, absolute responses before normalization (n = 244).
- Fig. 2.
Brief mechanical single whisker deflection causes a center-surround triphasic response. A, Frame sequence showing averaged cortical activation maps in response to brief (1 msec) mechanical stimulation of whisker D2 (4.8 msec/frame;n = 92 trials). B, Three time courses showing the averaged values from a ring-like shape at different distances from the barrel center. During the hyperpolarization phase, the response in the surround is more negative than the response in the center. The opposite is true for the earlier depolarization response.C, The net hyperpolarization gradually disappears on changing the duration of the stimulation from 1 msec to 30 msec.
- Fig. 3.
The VSD response to a strong cutaneous stimulus is triphasic. A, Frame sequence of averaged functional maps depicting the depolarization phase, followed by the hyperpolarization phase (n = 192 trials). Scale bar, 1 mm.B, Average normalized frame sequence across 10 experiments (n = 1638 trials). C,Time course of the triphasic response for the experiment shown inA. The three traces are at different distances from the barrel center. D, Average normalized time course of the triphasic response for the same 10 experiments. Different traces depict responses at different cortical distances from the point of maximal response. Inset, Same responses normalized to the peak of the depolarization phase. E, Average response as a function of the distance from the center of activity at different times. Black curves are Gaussian fits to the net depolarization minus the net hyperpolarization (see text). F, HWHH of positive Gaussian (red) and of negative Gaussian (blue). Fit during early depolarization (t <50 msec) is done only to the positive Gaussian. G, Late normalized response (t = 50–150 msec from stimulation onset) as a function of early response (t = 20 msec from stimulation onset), for different forces of cutaneous stimulation (n = 4 experiments, 488 trials).
- Fig. 4.
Stimulus-evoked 16 Hz oscillations seen in the positive rebound phase of the response. A, Average time course for a cutaneous stimulation (n = 192 trials), depicting the appearance of oscillations. B,Power spectrum performed on rebound depolarization phase ofA (from t = 155 msec).C, Contour plot showing that the spatial extent of the 16 Hz oscillations amplitude in the rebound phase (red) is similar to the spatial extent of the response in the initial depolarization phase, for the same data as in A. D, Comparison of a typical single trial, showing both ongoing and evoked activity (green), to average response from 75 trials (blue). Large ongoing activity is detected only in the trial without signal averaging (arrow).
