Cellular and Systems Mechanisms of L&M
May 30, 2017
May 30, 2017
University College, London, UK
Neural encoding of simple space
The brain has the task of organizing information coming in via the senses into representations, which help its owner behave adaptively in the world. Early "Behaviorist" ideas about representations supposed that these were simple networks of associations between stimuli, in which the nature of the stimuli did not matter. However, it gradually became apparent that not all stimuli are equal and that in fact, the brain treats different types of sensory input differently. The catalyst for this change in thinking was O'Keefe's discovery of place cells in the rat hippocampus, in the early 1970s. Subsequent study of place cells and their sensory antecedents revealed structures in the brain specialised for processing sensory information in different ways: for example, the visual input produced by sight of a landmark might be used to identify a place, determine facing direction, help estimate speed of movement or signpost a goal, and different parts of the brain handle these different tasks. This talk will introduce the hippocampal place system and describe its major components, and explore the way in which the study of the brain’s representation of space has also shed light on more general principles of cognitive representation.
Neural encoding of complex space
Studies of the hippocampal place system have previously mostly taken place in controlled laboratory environments in which animals were confined to single enclosures having simple geometry. However, the natural world is much more complex: it has multiple compartments or no compartments at all; it has complex surface topography such as hills, valleys, crevices, cliffs etc; it can be very small (a burrow) or very large (the ocean), and many animals, including our marine ancestors, can move freely in all three dimensions. This talk will explore the computational challenges faced by encoding complex space, and describe some of the studies that have begun to explore how mammalian brains deal with this complexity.