Topic: negative feedback

The superior colliculus (SC) is a major recipient of visual input in the mouse and controls innate approach and avoidance behaviours. Neurons in the superficial SC (sSC), which receives direct input from the retina, do not only process visual stimuli, but are also modulated by the animal’s running speed and pupil-linked arousal, similar to modulations observed in the primary visual cortex. While these observations were made during passive viewing of visual stimuli, a major purpose of vision is to guide behaviour. We therefore asked whether, in the context of a behavioural task, visual activity

Neural systems are remarkably robust against various perturbations, a phenomenon that still requires a clear explanation. Here, we graphically illustrate how neural networks can become robust. We study spiking networks that generate low-dimensional representations, and we show that the neurons’ subthreshold voltages are confined to a convex region in a lower-dimensional voltage subspace, which we call a ‘bounding box.’ Any changes in network parameters (such as number of neurons, dimensionality of inputs, firing thresholds, synaptic weights, or transmission delays) can all be understood as def

Collective behaviour operates without central control, through interactions among individuals. The collective behaviour of ant colonies is based on simple olfactory interactions. Ant species differ enormously in the algorithms that regulate collective behaviour, reflecting diversity in ecology. I will contrast two species in very different ecological situations. Harvester ant colonies in the desert, where water is scarce but conditions are stable, regulate foraging to conserve water. Response to positive feedback from olfactory interactions depends on the risk of water loss, mediated by dopa

Cognitive flexibility is characterized by the ability to adapt behavior in response to changing environments. When the environment changes, previously appropriate behavior can lead to negative feedback. Surprising negative feedback – failure to receive a reward when strongly expected – may signal a change in the environment and the need to adjust action plans. Thus, processes that compute confidence and detect feedback at the timescale of individual decisions should interact with slower processes that infer environment changes. The neural mechanisms that underlie these hierarchical decisions r