TESTING MODELS OF SIGNAL INTEGRATION IN MT Valerio Mante, Najib Majaj, Matteo Carandini, J. Anthony Movshon ETH and University of Zurich Howard Hughes Medical Institute and New York University

Gratings and plaids

Models of MT direction selectivity SH pattern model (Simoncelli and Heeger 1998) Component model (Movshon et al. 1983) Abstract Pattern model (Movshon et al. 1983)

The stimuliand their velocities

Responses of three MT cells

Component model

Abstract pattern model

SH pattern model

SH pattern model cells sum the output of the appropriate V1 cells

The direction tuning of SH pattern model cells for slow gratings is bimodal

Comparison of the models for the 3 cells

Comparison of the models for 39 cells

Conclusions To fit our data, we extended the original abstract component and pattern models and simplified the SH pattern model. Overall, the SH pattern model and the abstract pattern model performed equally well. But the SH model has fewer free parameters. The SH pattern model predicts some properties that are not explained by the other two.