@article {69748, title = {Conjoint specification of action by neocortex and striatum}, journal = {Neuron}, year = {2025}, month = {2025 Jan 20}, abstract = {

Summary The interplay between two major forebrain structures{\textemdash}cortex and subcortical striatum{\textemdash}is critical for flexible, goal-directed action. Traditionally, it has been proposed that striatum is critical for selecting what type of action is initiated, while the primary motor cortex is involved in specifying the continuous parameters of an upcoming/ongoing movement. Recent data indicate that striatum may also be involved in specification. These alternatives have been difficult to reconcile because comparing very distinct actions, as is often done, makes essentially indistinguishable predictions. Here, we develop quantitative models to reveal a somewhat paradoxical insight: only comparing neural activity across similar actions makes strongly distinguishing predictions. We thus developed a novel reach-to-pull task in which mice reliably selected between two similar but distinct reach targets and pull forces. Simultaneous cortical and subcortical recordings were uniquely consistent with a model in which cortex and striatum jointly specify continuous parameters governing movement execution.

}, keywords = {action selection, action specification, Basal Ganglia, computational model, motor control, Motor Cortex, neuropixels, Optogenetics, reinforcement learning, striatum}, issn = {0896-6273}, doi = {https://doi.org/10.1016/j.neuron.2024.12.024}, url = {https://www.sciencedirect.com/science/article/pii/S089662732400922X}, author = {Junchol Park and Peter Polidoro and Catia Fortunato and Jon Arnold and Brett Mensh and Juan A. Gallego and Joshua T. Dudman} } @article {69228, title = {Distinct streams for supervised and unsupervised learning in the visual cortex}, journal = {bioRxiv}, year = {2024}, month = {2024 Feb 27}, abstract = {

Representation learning in neural networks may be implemented with supervised or unsupervised algorithms, distinguished by the availability of feedback. In sensory cortex, perceptual learning drives neural plasticity, but it is not known if this is due to supervised or unsupervised learning. Here we recorded populations of up to 90,000 neurons simultaneously from the primary visual cortex (V1) and higher visual areas (HVA), while mice learned multiple tasks as well as during unrewarded exposure to the same stimuli. Similar to previous studies, we found that neural changes in task mice were correlated with their behavioral learning. However, the neural changes were mostly replicated in mice with unrewarded exposure, suggesting that the changes were in fact due to unsupervised learning. The neural plasticity was concentrated in the medial HVAs and obeyed visual, rather than spatial, learning rules. In task mice only, we found a ramping reward prediction signal in anterior HVAs, potentially involved in supervised learning. Our neural results predict that unsupervised learning may accelerate subsequent task learning, a prediction which we validated with behavioral experiments.

}, doi = {10.1101/2024.02.25.581990}, url = {https://www.biorxiv.org/content/early/2024/02/27/2024.02.25.581990}, author = {Lin Zhong and Scott Baptista and Rachel Gattoni and Jon Arnold and Daniel Flickinger and Carsen Stringer and Marius Pachitariu} } @article {69036, title = {Conjoint specification of action by neocortex and striatum.}, journal = {bioRxiv}, year = {2023}, month = {2023 Oct 05}, abstract = {

The interplay between two major forebrain structures - cortex and subcortical striatum - is critical for flexible, goal-directed action. Traditionally, it has been proposed that striatum is critical for selecting what type of action is initiated while the primary motor cortex is involved in the online control of movement execution. Recent data indicates that striatum may also be critical for specifying movement execution. These alternatives have been difficult to reconcile because when comparing very distinct actions, as in the vast majority of work to date, they make essentially indistinguishable predictions. Here, we develop quantitative models to reveal a somewhat paradoxical insight: only comparing neural activity during similar actions makes strongly distinguishing predictions. We thus developed a novel reach-to-pull task in which mice reliably selected between two similar, but distinct reach targets and pull forces. Simultaneous cortical and subcortical recordings were uniquely consistent with a model in which cortex and striatum jointly specify flexible parameters of action during movement execution.

}, doi = {10.1101/2023.10.04.560957}, url = {https://doi.org/10.1101/2023.10.04.560957}, author = {Junchol Park and Peter Polidoro and Catia Fortunato and Jon Arnold and Brett Mensh and Juan A. Gallego and Joshua T. Dudman} }