TY - JOUR T1 - Sensitivity of Neurons in the Middle Temporal Area of Marmoset Monkeys to Random Dot Motion JF - bioRxiv DO - 10.1101/104117 SP - 104117 AU - Tristan A. Chaplin AU - Benjamin J. Allitt AU - Maureen A. Hagan AU - Nicholas S. Price AU - Ramesh Rajan AU - Marcello G.P. Rosa AU - Leo L. Lui Y1 - 2017/01/01 UR - http://biorxiv.org/content/early/2017/02/23/104117.abstract N2 - Neurons in the Middle Temporal area (MT) of the primate cerebral cortex respond to moving stimuli. Their sensitivity to noisy motion signals is often characterized by using random-dot stimuli, where the coherence of the motion signal is manipulated. In macaques, this has allowed the calculation of "neurometric" thresholds, which can be compared to the animal’s behavioral performance. There has been growing interest in the marmoset monkey, a species in which area MT is fully exposed on the surface of the brain, but responses of MT neurons to random-dot stimuli with noise have not been characterized. In sufentanil/nitrous oxide anesthetized marmosets, we found that MT neurons show a wide range of neurometric thresholds, similar to observations in macaques, and that the thresholds of the most sensitive neurons can account for the behavioral performance of macaques and humans. We also investigated factors that contributed to the wide range of observed thresholds. The difference in firing rate between responses to motion in the preferred and null directions was the most effective predictor of neurometric threshold, whereas the direction tuning bandwidth had no correlation with the threshold. We also showed that it is possible to obtain good neurometric thresholds using stimuli that were not highly optimized for each neuron, as is often necessary when recording from large populations of neurons. These results demonstrate that marmoset MT shows an essential similarity to macaque MT, and suggests that it is capable of representing motion signals that would allow for comparable motion-in-noise judgments. ER -