Figure 5. Analysis of single-trial activity reveals state-dependent gating of interhemispheric interactions.
(A) Modulation of interhemispheric interactions necessary for modularity and error correction in a hemisphere (‘analyzed hemisphere’).
(B) Key elements of the predictive model of ALM activity. Left, the analyzed hemisphere is in the highly selective state or weakly selective state depending on the strength of activity projection on the choice decoder (CD). Right, the strength of interhemispheric influence is modulated depending on the state of the analyzed hemisphere.
(C) 3 example “lick right” trials (top) and 3 example “lick left” trials (bottom). Model prediction is restricted to the late delay epoch (Methods). Gray, weakly selective state. Time bin, 400 ms; time step, 100 ms.
(D) Left, interhemispheric input inferred from control trials versus selectivity recovery in photoinhibition trials. The interhemispheric input is the selectivity in the unperturbed hemisphere multiplied with the interhemispheric coefficient (β0 in the weakly selective state, Methods). Right, the inferred interhemispheric input versus behavioral performance in photoinhibition trials. Circles, sessions from the standard task; triangle, fully reversed task. Filled symbols, left ALM photoinhibition; open symbols, right ALM photoinhibition. Line, linear regression and Pearson’s correlation. 98 sessions, 28 mice.
(E) The strength of interhemispheric influence when the analyzed hemisphere is in the weakly versus highly selective state. The interhemispheric influence is the improvement of model prediction by incorporating interhemispheric influence on top of within-hemisphere influence (ΔR2, Methods). Circles, single hemispheres in individual sessions. Bar, mean. 98 sessions. ***, p<0.001, two-tailed t-test.
(F) Example session showing effects of contralateral photoinhibition when the analyzed hemisphere is in the weakly versus highly selective state. Dashed lines, activity in control trials (mean ± s.e.m.); solid lines, example photoinhibition trials. Trials are sorted into highly selective or weakly selective (gray area) based on the CD projection before photoinhibition (Methods). Blue, “lick right”; red, “lick left”. Cyan bars, photoinhibition period.
(G) Activity change caused by photoinhibition relative to control trials (Methods). Data from all sessions and both ALM hemispheres (n=20). Mean ± s.e.m. across sessions.
See also Figure S6.