Probabilistic Reasoning by Neurons

The following supplementary movies are prepared for the journal publication

Yang, T and Shadlen, MN (2007), Probabilistic reasoning by neurons, Nature 447, 1075-1080

These movies reproduce the sequence of events on six representative trials from the experiment. The diagrams in this appendix depict the content of each of the movies. Versions of these diagrams are also reproduced dynamically at the bottom of the movies. Each movie begins with acquisition of the fixation point (FP) and ends with a saccadic eye movement to the red or the green target.

The moving yellow dot shows the eye position of the monkey during the trial. In the bottom of the movie, spike trains are shown as ticks along the time line. The traces depict the changing logLR associated with the appearance of the shapes; height reflects the logLR in favor of Tin. The color of the trace in the movies indicates whether the evidence currently favors the red or the green target. Neither the eye position trace nor the diagrams were shown on the video display that was viewed by the monkey. The movie soundtrack plays the spikes from the neuron. There is a prominent transient response to the targets in the beginning of the 1st epoch. The four shapes cause the firing rate to increase or decrease ~200 ms after each is displayed. Movies 1-3 are from the example neuron depicted in Figure 2 (RF below and to the right of fixation). Movies 4-6 are from three other neurons. All six neurons have their RF location in the right visual field. Note that the same shape can cause different changes of logLR in different epochs (e.g., Movie 1), as explained in Online Methods.

Click the diagrams below to view the movies. Please note that these movies are converted from original .mov format to .m4v format for play in Quicktime 10.4.