RT Journal Article SR Electronic T1 Contribution of Cholinergic and GABAergic Mechanisms to Direction Tuning, Discriminability, Response Reliability, and Neuronal Rate Correlations in Macaque Middle Temporal Area JF The Journal of Neuroscience JO J. Neurosci. FD Society for Neuroscience SP 16602 OP 16615 DO 10.1523/JNEUROSCI.0554-12.2012 VO 32 IS 47 A1 Alexander Thiele A1 Jose L. Herrero A1 Claudia Distler A1 Klaus-Peter Hoffmann YR 2012 UL http://www.jneurosci.org/content/32/47/16602.abstract AB Previous studies have investigated the effects of acetylcholine (ACh) on neuronal tuning, coding, and attention in primary visual cortex, but its contribution to coding in extrastriate cortex is unexplored. Here we investigate the effects of ACh on tuning properties of macaque middle temporal area MT neurons and contrast them with effects of gabazine, a GABAA receptor blocker. ACh increased neuronal activity, it had no effect on tuning width, but it significantly increased the direction discriminability of a neuron. Gabazine equally increased neuronal activity, but it widened tuning curves and decreased the direction discriminability of a neuron. Although gabazine significantly reduced response reliability, ACh application had little effect on response reliability. Finally, gabazine increased noise correlation of simultaneously recorded neurons, whereas ACh reduced it. Thus, both drugs increased firing rates, but only ACh application improved neuronal tuning and coding in line with effects seen in studies in which attention was selectively manipulated.