Electrophysiology of covert attention in area PITd
Supplemental Videos for "An Attentional Priority Map in Inferotemporal Cortex" by Stemmann and Freiwald
This movie illustrates the spatial layout and the temporal sequence of a trial of the attentive motion-discrimination paradigm. Stimulus events are slowed down for clarity. The basic spatial layout consists of the central fixation point (FP), which has to be foveated throughout the trial, the bar cue (to the left of the fixation spot) indicating which of the two random dot surfaces, one to the left, the other to the right of the FP, is to be attended, two random dot surfaces, and eight saccade targets in the periphery. The saccade targets are positioned at equidistant locations from the FP. The random dot surfaces undergo rapid random changes in motion transition, which are interrupted, at a point in time unpredictable by the subject, by a prolonged motion event (PME). In the example in this movie the distracter PME on the right occurs prior to the target PME. Since the target’s PME direction is towards the upper right, a saccade to that location would need to be made for successful completion of the trial.
This movie shows live video taken during the first PITd recording while the subject was successfully performing six trials of the attentive motion discrimination task. The top shows the control monitor on which the hand-mapped receptive field (RF) is marked on a transparent plastic sheet on top of a control monitor that shows the stimuli as the subject was seeing them. The activity of the simultaneously recorded multi-unit activity can be heard. At the bottom, the average PSTHs for the two attention conditions are shown, light red for ‘attend into RF’, and grey for ‘attend away from RF’. The instantaneous firing rates (causally smoothed with half Gaussian) are plotted online in red and white (for ‘attend into RF’ and ‘attend away from RF’ conditions, respectively). At the end of the trial, the outcome (‘Hit’) is indicated and in case of a successful completion, the sound of the solenoid controlling juice reward can be heard opening and closing as a click. The first trial is an ‘attend in RF’ condition (red) – the bar cue is to the left of the fixation spot. The following three trials are ‘attend away from RF’ conditions, and the final two trials again, ‘attend into RF’ conditions.
This movie shows the same live recording as S2, but an error trial. All conditions and conventions as in S2. The cue is placed to the right of the fixation spot, thus the subject’s task was to pay attention to the right random dot surface (‘attend away from RF’ condition, white). Yet activity is as high as it would be, on average, when attention is paid into the RF. And the subject is responding to the prolonged motion event on the distractor surface, thus completing the trial as an error.
