Figure 6. Population vector rotation.

(A) Schematics of hypotheses tested in this figure. Hypothesis I: the population vector in the sustained period is a linearly scaled version of that at stimulus onset. Hypothesis II: both the magnitude and direction of the population vector changes. (B1) Pseudocolor plot showing the angle in degrees between the mean population firing rate vectors for all times and tone frequencies, and a reference vector produced by a 14.4 kHz tone during stimulus onset (indicated by the arrow). The reference vector is more similar to onset response vectors for other frequencies, than to sustained responses for the same tone. (B2) Similar analysis for a reference vector computed during the sustained response, here showing greater similarity to sustained responses of other stimuli, than to onset responses to the same stimulus. (B3-4) Same as B1-2, with 27 kHz tone response as reference. Adapted from Bartho et al (2009).