TY - JOUR T1 - <em>In Vivo</em> Two-Photon Ca<sup>2+</sup> Imaging Reveals Selective Reward Effects on Stimulus-Specific Assemblies in Mouse Visual Cortex JF - The Journal of Neuroscience JO - J. Neurosci. SP - 11540 LP - 11555 DO - 10.1523/JNEUROSCI.1341-12.2013 VL - 33 IS - 28 AU - Pieter M. Goltstein AU - Emily B. J. Coffey AU - Pieter R. Roelfsema AU - Cyriel M. A. Pennartz Y1 - 2013/07/10 UR - http://www.jneurosci.org/content/33/28/11540.abstract N2 - Experiences can alter functional properties of neurons in primary sensory neocortex but it is poorly understood how stimulus–reward associations contribute to these changes. Using in vivo two-photon calcium imaging in mouse primary visual cortex (V1), we show that association of a directional visual stimulus with reward results in broadened orientation tuning and sharpened direction tuning in a stimulus-selective subpopulation of V1 neurons. Neurons with preferred orientations similar, but not identical to, the CS+ selectively increased their tuning curve bandwidth and thereby exhibited an increased response amplitude at the CS+ orientation. The increase in response amplitude was observed for a small range of orientations around the CS+ orientation. A nonuniform spatial distribution of reward effects across the cortical surface was observed, as the spatial distance between pairs of CS+ tuned neurons was reduced compared with pairs of CS− tuned neurons and pairs of control directions or orientations. These data show that, in primary visual cortex, formation of a stimulus–reward association results in selective alterations in stimulus-specific assemblies rather than population-wide effects. ER -