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Authors & Affiliations
Dario Campagner,Ruben Vale,Panagiota Iordanidou,Oriol Pavon Arocas,Yu Lin Tan,Federico Claudi,Anna Vanessa Stempel,Sepiedeh Keshavarzi,Rasmus Strange Petersen,Troy Margrie,Tiago Branco
Abstract
Escaping towards shelter is an adaptive behaviour offering protection against predation. In mice, this is preceded by a fast, memory-guided head rotation towards the shelter[1]. It is not known how the escape circuit incorporates spatial information to execute rapid and accurate flights to safety. Here we show that retrosplenial cortex (RSP) and superior colliculus (SC) form a monosynaptic circuit that continuously encodes shelter direction and is necessary for spatially-accurate escape.
Using Neuropixels probes, we found head-shelter angle cells (HSAC) in RSP and SC. Both multivariate tuning curve analysis and generalized linear models showed HSA to be a key predictor of their firing rate. HSACs tile angular space such that HSA can be decoded accurately at the population level. Rabies tracing and channelrhodopsin-assisted circuit mapping revealed that both excitatory and inhibitory SC neurons receive monosynaptic input from RSP. This synapse is critical for HSA encoding in SC and accurate escape: chemogenetic inactivation of SC-projecting RSP neurons disrupted single-cell and population encoding of HSA in SC and resulted in inaccurate orientation to shelter during escape. No impairment was observed in sensory-guided orientation nor navigation-to-reward tasks, suggesting that RSP input to SC selectively conveys shelter position, but is not necessary for SC-based motor control. Next, we probed HSA encoding and population dynamics in excitatory and inhibitory SC neurons in response to RSP input using dual-opsin RSP stimulation and optotagging in vivo. We found an activity pattern compatible with RSP input mapping HSA onto the SC network using a centre-surround inhibition mechanism, that was modelled using spiking-RNNs constrained by experimental data.
Combining molecular, computational and electrophysiological techniques, we identified a circuit-motif through which spatial memories are transmitted to a motor-control area to guide goal-directed behaviour. This cortical-subcortical interface may be a general blueprint for increasing the flexibility of instinctive behaviours.
[1]Vale et al.,2017,Current Biology