Response profiles of oscillatory cell to a train of light stimuli.

<p>(<b>A</b>, <b>B</b>) Firing rate histograms of oscillatory OPN neuron during train stimulation with 3 second long light flashes (•).Grey dashed sinusoid lines superimposed on histograms reflect baseline oscillation periods. (<b>A</b>) The oscillation-preserving response profile was characterized by low responsiveness during active phase of oscillatory cycle and marked augmentation of activity during silent phase of oscillation. Occurrence of this profile was associated with low-intensity light stimulations and does not interrupted slow oscillatory pattern. The oscillation-disrupting response profile (<b>B</b>) was characterized by similar responsiveness to each stimulus and was apparent at high-intensity light stimulations. Spectral analysis of the 260 second long segment of the histogram (marked with blue dashed line) using FFT algorithm confirmed oscillation-preserving (<b>C</b>) or oscillation-disrupting (<b>D</b>) modes of response. Note that the peak location in <b>C</b> (115 s) correspond to observed period of oscillation. Plot <b>D</b> is lacking the peak at a similar location but instead significant periodicity was detected at 20 second (indicated by an arrow), matching rhythmicity of the stimulation and reflecting responses of the cell. (<b>E</b> and <b>F</b>) individual light-induced activity changes calculated from respective activity histograms and measured as a number of spikes generated during 3 seconds preceding a stimulus (1) and during a light flash (2). Note that activity changes plotted in <b>E</b> are not consistent and when high baseline activity takes place, the response is dampened (red lines).