Stefano Fusi - US grants

Understanding how a healthy brain interprets sensory signals and guides actions, and why an unhealthy brain fails to perform these functions properly, is a profound and ambitious goal of 21st century science. Integrating knowledge of neural circuit function into a coherent picture of perception, cognition and action requires extraordinary cooperation and coordination between three research areas: experimentation, data analysis and modeling. The National Science Foundation Theory Team at Columbia University will unite exceptional resources in statistical data analysis and theoretical modeling with an extensive network of experimental collaborators to address the enormous challenges facing neuroscience. Never has the need been greater for theoretical insights and sophisticated data analysis. The field of neuroscience is facing a torrent of complex data from a system that is, itself, extraordinarily complex. Future progress requires developing the ability to extract knowledge and understanding from these data through analyses and modeling that capture the essence of what they mean. The goal of the NeuroNex Theory Team at Columbia is to establish, through the quality of its research, the excellence of its trainees, and the impact of its visitor, dissemination, and outreach programs, a new cooperative paradigm that will move neuroscience to unprecedented levels of discovery and understanding.

High-density electrode recording, wide-field calcium imaging and complex connectivity mapping are bringing neuroscience into an era of extensive multi-area and even whole-brain studies of neural activity and circuitry. The neuroscience community desperately needs new ways of interpreting data obtained from different species using myriad techniques and for thinking about neural processing over large length and time scales and across multiple brain areas. In response to these challenges, two major goals will drive and define research at the NeuroNex Theory Team at Columbia: first, integrating the analysis methods and theoretical models used to infer meaning from data with each other and with the experiments that generate these data; and second, providing analytic tools and theoretical frameworks to understand interactions between multiple brain regions and to draw important overarching lessons from experiments exploiting a variety of techniques across different species. Progress will be made through a tight integration of theoretical techniques with outstanding experimental collaborators working on a variety of systems and species. Graduate and postdoctoral training will stress technical excellence and broad perspectives in both theoretical and experimental neuroscience. Outreach will be made to other researchers through visitor and exchange programs, sponsored meetings and dissemination of research results and high-quality, user-friendly software. Outreach will be made to the broader community by sharing the excitement of neuroscience research with elementary and high school students and with the general public. This NeuroNex Theory Team award is co-funded by the Division of Emerging Frontiers within the Directorate for Biological Sciences, the Division of Physics and the Division of Mathematics within the Directorate of Mathematical and Physical Sciences, and by the Division of Brain and Cognitive Sciences within the Directorate of Social, Behavioral and Economic Sciences, as part of the BRAIN Initiative and NSF's Understanding the Brain activities.

ABSTRACT Visual learning is critical to the lives of human and non-human primates. Visuomotor association, the assignment of an arbitrary symbol to a particular movement (like a red light to a braking movement), is a well- studied form of visual learning. This proposal tests the hypothesis that the brain accomplishes visuomotor associative learning using an anatomically defined closed-loop network, including the prefrontal cortex, the basal ganglia, and the cerebellum. In our preliminary work we have developed a task that studies how monkeys learn to associate one of two novel fractal symbols with a right hand movement, and the other symbol with a left hand movement. Every experiment begins with the monkeys responding to two overtrained symbols that they have seen hundreds of thousands of times. At an arbitrary time we change the symbols to two fractal symbols that the monkey has never seen. It takes the monkey 40 to 70 trials to learn the new associations. In our preliminary results we have discovered that Purkinje cells in the midlateral cerebellar hemisphere track the monkeys? learning as they as they figure out the required associations. The neurons signal the result of the prior decision. Half of the neurons respond more when the prior decision was correct; the others respond more when the prior decision was wrong. The difference between the activity of these two types of neurons provides a cognitive error signal that is maximal when the monkeys are performing at a chance level, and gradually becomes not different from zero as the monkeys learn the task. The neurons do not predict the result of the impending decision. Although the neurons change their activity dramatically at the symbol switch, the kinematics of the movements do not change at all. This proposal takes this discovery as the starting point for four aims: 1) to use viral transynaptic tract tracing to discover the cortical and basal ganglia regions that project to the cerebellar visuomotor association area. 2) to record from the four nodes of the network as anatomically defined (midlateral cerebellar hemisphere, dentate nucleus, basal ganglia, prefrontal cortex), simultaneously, using multiple single neuron recordings, to see if these areas also have information about the process of visuomotor association 3) to inactivate each node, to see how their inactivation affects the monkey?s ability to learn new associations, and whether the inactivation affects the activity of the neurons at the other nodes. 4) to develop computational methods to analyze the activity of neural activity recorded simultaneously in all four nodes of the network (Aim 2) in the midlateral cerebellar cortex with regard to parameters such as prior outcome and movement, hand, symbol, and the intensity and epoch of the prior cognitive error signal. We will use dimensional reduction techniques to answer questions like whether hand or symbol can be decoded from network activity. We will model how the cerebellum simple spike cognitive error signal might propagate through the network and be used to facilitate visuomotor association learning and the processing of signals in the cerebellum, basal ganglia and cerebral cortex

Detailed description of the proposed use of the animals, including species, strains, ages, sex, and number to be used; Dissociated, primary cultures will be prepared from the cortex of new born mice of either sex (mus musculus, Postnatal day 0-1). These experiments will be performed using pups obtained from Vglut1-IRES2-Cre strains mated with Floxopatch (Lou et al., 2016) strains so that pyramidal cells will express channel rhodopsin CheRiff and voltage indicator QuasR2. Up to 5 cultures can be grown, which can be used for 5 experiments. Justification for the use of animals, choice of species, and numbers to be used; Description of procedures for minimizing discomfort, distress, pain, and injury; and Method of euthanasia and the reasons for its selection. Transgenic mice (category C) will be used because the experiments rely on the expression of CheRiff and QuasR2 for optical stimulation/recording. There are no alternative species. All experiments are terminal. Newborn mice will be cooled in ice prior to cervical dislocation and excision of the brain for culture preparation. All procedures are in accordance with guideleines of the NYU Animal Welfare Committee. The estimated number of animals below ensure that we have a continuous supply of cultures to perform experiments on a daily basis. Based on our experience in the past 3 years, each postnatal day 0-1 (P0-P1) mouse will generate at least 5 culture preparations. A viable culture will have a have a high density of neurons that express the Floxopatch construct, which varies from mouse to mouse. Thus, if one culture is not viable, all cultures derived from that mouse are also unusable. The success rate is approximately 50%. Because cultures can be made only form P0-1 day old mice and because it is not possible to determine whether expression is sufficient until the day of the experiment 2-3 weeks later, we will need to make 2 sets of cultures per week. Thus, we will need to maintain 2 breeding pairs per week or 8 breeding pairs per month to have a continuous supply of cultures. The breeding pairs will either consist of wildtype mice (for viral injection) or Vglut1-IRES2-Cre - Gt(ROSA)26Sor (floxopatch) mice. Breeding pairs will be replaced every six months. Total animals for experiments: 32 mice/year (=16 mice (8 breeding pairs) x 2/year replacement of breeding pairs). To maintain the 3 lines, 2 males and 2 females each of Vglut1-IRES2-Cre, Gt(ROSA)26Sor, and wildtype mice will be kept in separate cages (4+4+4=12 mice total). Every 6 months (twice per year), the mice of each type will be bred. From their offsprings, 4 males and 4 females from each line will be weaned and kept in separated cages as above (4+ 4 + 4 = 12) and the 4 original breeding pairs (12 mice) euthanized. Overall, 24 mice/year will be used to maintain the lines. Total mice/year: 56 (=24 mice/year to maintain lines + 32 mice/year for experiment). Total mice over 3 years = 168 mice. Reference Lou et al., (2016) Genetically Targeted All-Optical Electrophysiology with a Transgenic Cre-Dependent Optopatch Mouse, J. Neurosci. 36:11059-73 1 53 Results from previous support from CRCNS The P.I. and co-P.I. have not received previous CRCNS support Coordination Plan Division of labor The P.I. (A. Reyes) and his group at NYU will perform the experiments and analyses detailed in Aims 1 and 2 of this proposal. The co-P.I (S. Fusi) and his group at Columbia University will be responsible for the development of the theory and computational models that will incorporate the experimental data. Data Sharing between NYU and Columbia groups: Analyzed data, model codes, and manuscripts in progress will be disseminated between the groups via Google drive. All members of the Fusi and Reyes groups will have access upon email request. Larger, raw data will be stored on local servers and accessible via FTP. Coordination between NYU and Columbia University Because NYU and Columbia are easily acces- sible by subway, we will have monthly joint lab meetings, alternating between NYU and Columbia. Graduate students and postdoctoral fellows will be encouraged to submit joint poster presentations or talks to annual meetings such as Cosyne and Society for Neuroscience Meetings. 16 54