Up
Previous
Next
Novel effects of adaptation in area MT
Adam Kohn and J. Anthony Movshon
NYU
We have evaluated the effect of prolonged (40 s) adaptation on the
direction tuning of macaque area MT/V5 neurons using drifting sine
wave gratings. Preferred adaptation consistently caused a narrowing
of direction tuning, because the response in the adapted direction was
reduced less strongly than that in other nearby directions. A similar
phenomenon was observed following adaptation at near-preferred
('flank') directions, with the consequence that the direction tuning
of MT cells was attracted toward the adapted direction. Flank
adaptation of complex cells in primary visual cortex (V1) did not
cause an attractive shift in direction tuning. Finally, null
adaptation often caused an increase in direction tuning bandwidth in
MT neurons, but did not alter their preferred direction or
responsivity. We suggest that these novel effects of adaptation on
direction tuning in area MT are consistent with perceptual
aftereffects and provide functional benefits not afforded by the
repulsive shifts in tuning typically observed in V1.