Motor-driven modulation in visual neural circuits

Abstract

Experiments in anesthetized, immobile animals have contributed to the classical view that sensory and motor functions in the brain are separated processes. However, under natural conditions, the nervous system and the body of a moving animal interact continuously, and it is from this interaction that neural circuits in the brain form an internal representation of the sensory world. We move our head to detect and localize the source of a sound, we move our eyes to scan a visual scene; likewise, tactile sensation is based on our body's movement, and olfaction occurs in the context of sniffing. Sensory and motor components of a sensory modality are intimately connected to each other during an active process. How this relation is implemented across sensorimotor circuits, and how motor-sensory coordination improves sensation, are questions that still remain unclear. Recent technological advances have made possible to record neural activity from sensory areas while animals walk or fly-behavioral conditions in which sensation most frequently happens. From these studies, performed both in insects and mammals, it has become apparent that the neural dynamics of primary sensory areas are readily influenced by ongoing locomotion. In this chapter, we discuss work dissecting different components of the locomotion-dependent modulations, focusing on visual circuits in flies and mice. The presence of these locomotive-related signals in early visual centers strongly suggests that motor-sensory coordination is dynamic, diverse, and adaptable to the behavioral situation of the animal.