Venue: Centre Broca
Daniel Huber Group, Department of Basic Neuroscience
University of Geneva, Switzerland
Invited by Mario Carta (IINS)
What but not how: motor cortex neurons in mice encode movement goals rather than its kinematics
Motor cortex controls voluntary movements through descending commands via the brainstem and spinal cord. To better understand the cortical role in motor control, we studied the activity of layer 2/3 motor cortex neurons of mice performing a multi-directional water-reaching task. We found that task-related neurons became sequentially active across all phases of the behavior: from target presentation to reaching and water consumption. Interestingly, while all task-related neurons displayed strong selectivity for the location of the reaching target, few were modulated by the arm’s actual trajectory. This suggests that task-related neurons encode spatial information of reaching endpoints rather than kinematic parameters of movements. We analyzed this spatial representation and found that neurons were clustered into three roughly segregated groups representing reaching targets located to the left, center or right of the animal’s snout, conforming a coarse reaching endpoint map. As a whole, subsets of layer 2/3 neurons represent specific combinations of spatial and temporal aspects of the task. We hypothesized that these subsets form functional modules that are recruited dynamically during task execution. To test this hypothesis, we analyzed the neuronal activity while the reaching target was suddenly moved from one location to another during an ongoing reach. As predicted, activity of the neuronal modules was consistently updated to match the novel target location and upcoming phases of the task. In summary, our data suggests that cortical activity in the mouse does not solely reflect motor commands, but processes spatio-temporal information related to the ongoing behavior and we speculate that layer 2/3 motor cortex neurons play a cognitive role related to attentional or perceptual mechanisms.
Galiñanes GL, Bonardi C, Huber D. Directional Reaching for Water as a Cortex-Dependent Behavioral Framework for Mice. Cell Rep. 2018 Mar 6;22(10): 2767-2783.doi: 10.1016/j.celrep.2018.02.042. PMID: 29514103; PMCID: PMC5863030.
Prsa M, Galiñanes GL, Huber D. Rapid Integration of Artificial Sensory Feedback during Operant Conditioning of Motor Cortex Neurons. Neuron. 2017 Feb 22;93(4):929-939.e6. doi: 10.1016/j.neuron.2017.01.023. PMID: 28231470; PMCID: PMC5330804.
Galiñanes GL, Huber D. Circuits for Raiders. Neuron. 2018 Sep 5;99(5):872-873. doi: 10.1016/j.neuron.2018.08.024. PMID: 30189206.
Galiñanes GL, Marchand PJ, Turcotte R, Pellat S, Ji N, Huber D. Optical alignment device for two-photon microscopy. Biomed Opt Express. 2018 Jul 9;9(8):3624-3639. doi: 10.1364/BOE.9.003624. PMID: 30338144; PMCID: PMC6191613.
Andrásfalvy BK, Galiñanes GL, Huber D, Barbic M, Macklin JJ, Susumu K, Delehanty JB, Huston AL, Makara JK, Medintz IL. Quantum dot-based multiphoton fluorescent pipettes for targeted neuronal electrophysiology. Nat Methods. 2014 Dec;11(12):1237-1241. doi: 10.1038/nmeth.3146. Epub 2014 Oct 19. PMID: 25326662; PMCID: PMC4245189.
Barkus C, Bergmann C, Branco T, Carandini M, Chadderton PT, Galiñanes GL, Gilmour G, Huber D, Huxter JR, Khan AG, King AJ, Maravall M, O’Mahony T, Ragan CI, Robinson ESJ, Schaefer AT, Schultz SR, Sengpiel F, Prescott MJ. Refinements to rodent head fixation and fluid/food control for neuroscience. J Neurosci Methods. 2022 Nov 1;381:109705. doi: 10.1016/j.jneumeth.2022.109705. Epub 2022 Sep 9. PMID: 36096238.