Responses of Neurons in the Medial Superior Temporal Visual Area to Apparent Motion Stimuli in Macaque Monkeys
- 1 January 2007
- journal article
- research article
- Published by American Physiological Society in Journal of Neurophysiology
- Vol. 97 (1), 272-282
- https://doi.org/10.1152/jn.00941.2005
Abstract
Monkeys fixated a stationary spot during presentation of dot textures that moved in apparent motion defined by the spatial and temporal separations, Δx and Δt, between successive flashes of each dot. For each neuron, we assessed the speed tuning for smooth motion (Δt = 2 or 4 ms) at speeds ≤128°/s and the effect of varying the value of Δt at speeds of 16 and 32°/s. Many medial superior temporal (MST) neurons, like middle temporal (MT) neurons, were tuned for the speed of smooth motion and showed decreases in firing rate as the value of Δt increased at a constant speed. A subset of MST neurons, however, showed monotonically increasing firing rates as a function of smooth stimulus speed and responses to apparent motion that paralleled a previously discovered illusion where estimates of target speed increase with the value of Δt. Opponent firing rate, defined as the difference between responses for motion in the preferred and opposite directions, peaked at values of Δt that were consistent with the behavioral illusion. Comparison with a new sample of MT neurons recorded with the same stimuli failed to reveal comparable effects. Attempts to map the population responses in MT and MST onto the behavioral illusion of increased speed succeeded by averaging the opponent response across MST neurons, but only by applying vector averaging to determine the preferred speed of the most active MT neurons. We suggest that a vector-averaging computation transforms MT's place code for target speed into the rate code of some MST neurons.Keywords
This publication has 23 references indexed in Scilit:
- Tuning for Spatiotemporal Frequency and Speed in Directionally Selective Neurons of Macaque Striate CortexJournal of Neuroscience, 2006
- Relationship Between Extraretinal Component of Firing Rate and Eye Speed in Area MST of Macaque MonkeysJournal of Neurophysiology, 2005
- Normal Performance and Expression of Learning in the Vestibulo-Ocular Reflex (VOR) at High FrequenciesJournal of Neurophysiology, 2005
- Comparison of the Spatial Limits on Direction Selectivity in Visual Areas MT and V1Journal of Neurophysiology, 2005
- Converting neural signals from place codes to rate codesBiological Cybernetics, 2001
- The Speed Tuning of Medial Superior Temporal (Mst) Cell Responses to Optic-Flow ComponentsPerception, 1995
- Pathways for motion analysis: Cortical connections of the medial superior temporal and fundus of the superior temporal visual areas in the macaqueJournal of Comparative Neurology, 1990
- Cortical connections of visual area MT in the macaqueJournal of Comparative Neurology, 1986
- Model of human visual-motion sensingJournal of the Optical Society of America A, 1985
- Sequence regularity and geometry of orientation columns in the monkey striate cortexJournal of Comparative Neurology, 1974