@article {67235, title = {The anterior cingulate cortex directs exploration of alternative strategies.}, journal = {Neuron}, volume = {109}, year = {2021}, month = {2021 Jun 2}, pages = {1876-87}, abstract = {

The ability to adjust one{\textquoteright}s behavioral strategy in complex environments is at the core of cognition. Doing so efficiently requires monitoring the reliability of the ongoing strategy and, when appropriate, switching away from it to evaluate alternatives. Studies in humans and non-human primates have uncovered signals in the anterior cingulate cortex (ACC) that reflect the pressure to switch away from the ongoing strategy, whereas other ACC signals relate to the pursuit of alternatives. However, whether these signals underlie computations that actually underpin strategy switching or merely reflect tracking of related variables remains unclear. Here we provide causal evidence that the rodent ACC actively arbitrates between persisting with the ongoing behavioral strategy and temporarily switching away to re-evaluate alternatives. Furthermore, by individually perturbing distinct output pathways, we establish that the two associated computations-determining whether to switch strategy and committing to the pursuit of a specific alternative-are segregated in the ACC microcircuitry.

}, issn = {1097-4199}, doi = {10.1016/j.neuron.2021.03.028}, author = {Tervo, D Gowanlock R and Kuleshova, Elena and Manakov, Maxim and Proskurin, Mikhail and Karlsson, Mattias and Lustig, Andy and Behnam, Reza and Karpova, Alla Y} } @article {49474, title = {Expanding the optogenetics toolkit by topological inversion of rhodopsins.}, journal = {Cell}, volume = {175}, year = {2018}, month = {2018 Oct 16}, pages = {1131-40}, abstract = {

Targeted manipulation of activity in specific populations of neurons is important for investigating the neural circuit basis of behavior. Optogenetic approaches using light-sensitive microbial rhodopsins have permitted manipulations to reach a level of temporal precision that is enabling functional circuit dissection. As demand for more precise perturbations to serve specific experimental goals increases, a palette of opsins with diverse selectivity, kinetics, and spectral properties will be needed. Here, we introduce a novel approach of "topological engineering"-inversion of opsins in the plasma membrane-and demonstrate that it can produce variants with unique functional properties of interest for circuit neuroscience. In one striking example, inversion of a Channelrhodopsin variant converted it from a potent activator into a fast-acting inhibitor that operates as a cation pump. Our findings argue that membrane topology provides a useful orthogonal dimension of protein engineering that immediately permits as much as a doubling of the available toolkit.

}, issn = {1097-4172}, doi = {10.1016/j.cell.2018.09.026}, author = {Brown, Jennifer and Behnam, Reza and Coddington, Luke and Tervo, D G R and Martin, Kathleen and Proskurin, Mikhail and Kuleshova, Elena and Park, Junchol and Phillips, James and Bergs, Amelie C F and Gottschalk, Alexander and Dudman, Joshua T and Karpova, Alla Y} } @article {6579, title = {A neuron-based screening platform for optimizing genetically-encoded calcium indicators.}, journal = {PLoS One}, volume = {8}, year = {2013}, month = {2013}, pages = {e77728}, abstract = {

Fluorescent protein-based sensors for detecting neuronal activity have been developed largely based on non-neuronal screening systems. However, the dynamics of neuronal state variables (e.g., voltage, calcium, etc.) are typically very rapid compared to those of non-excitable cells. We developed an electrical stimulation and fluorescence imaging platform based on dissociated rat primary neuronal cultures. We describe its use in testing genetically-encoded calcium indicators (GECIs). Efficient neuronal GECI expression was achieved using lentiviruses containing a neuronal-selective gene promoter. Action potentials (APs) and thus neuronal calcium levels were quantitatively controlled by electrical field stimulation, and fluorescence images were recorded. Images were segmented to extract fluorescence signals corresponding to individual GECI-expressing neurons, which improved sensitivity over full-field measurements. We demonstrate the superiority of screening GECIs in neurons compared with solution measurements. Neuronal screening was useful for efficient identification of variants with both improved response kinetics and high signal amplitudes. This platform can be used to screen many types of sensors with cellular resolution under realistic conditions where neuronal state variables are in relevant ranges with respect to timing and amplitude.

}, issn = {1932-6203}, doi = {10.1371/journal.pone.0077728}, author = {Wardill, Trevor J. and Chen, Tsai-Wen and Schreiter, Eric R and Hasseman, Jeremy P and Tsegaye, Getahun and Fosque, Benjamin F and Behnam, Reza and Shields, Brenda C and Ramirez, Melissa and Kimmel, Bruce E and Kerr, Rex A and Jayaraman, Vivek and Looger, Loren L and Svoboda, Karel and Kim, Douglas S.} }