Fig. 2.

The recovery of MT neurons from short-term adaptation. A: histograms of the firing rate of an MT neuron showing its response to 2 brief 64-ms-duration presentations of motion with different condition/test intervals (CTI). The bold trace superimposed on each histogram shows the response to the conditioning motion alone. The bold and fine horizontal lines below the histograms show the times of the conditioning and test motions, respectively. The test and conditioning motion were both in the preferred direction and at the preferred speed of the neuron. B: assessment of the time course of recovery from short-term adaptation by plotting the firing rate evoked by the test motion as a function of the condition/test interval. These values were measured from the difference firing rate obtained by subtracting the response to the conditioning motion alone from the response to the conditioning/test stimulus. The horizontal dashed lines indicate 95% confidence intervals for the response of the neuron to the test motion without preceding conditioning motion, estimated as the mean response ±1 SE. The continuous curve indicates the exponential that provided the best fit to the recovery of the neuron. The time constant of recovery for this neuron was 73 ms. The error bars on the symbols indicate the standard error of the mean. C: histogram showing the distribution of the time constant of recovery for all the neurons in our sample population. The arrow indicates the mean recovery time constant of 86 ms.