Brain Dynamics

Abstract

Vision is an active and dynamic process.  The strategy our brain uses to parse scenes and recognize objects depends on experience.  Our interpretation of visual scenes requires an interaction between internal representations of object properties acquired through experience and the immediate information coming from the retina. These internal representations enable the brain’s analysis of scenes to be subject to top-down influences of attention, expectation, perceptual tasks, perceptual learning, working memory and motor commands.  At the level of brain circuitry this process involves an interaction between long range feedback and intrinsic cortical connections and enables neurons to assume different functional states according to the task being executed.  Underlying this functional switching neurons gate their inputs.  Although each neuron receives 10⁵ inputs from other neurons, neurons are capable of selecting a small subset of task relevant inputs and suppressing the influence of task irrelevant inputs.  The circuitry of the adult cortex therefore is under a continual long-term process

of modification as we assimilate new information, and short-term dynamics as we analyze the constituents of visual scenes.  These mechanisms are common to all regions of the brain, and when disrupted may account for visual and behavioral disorders.

Our ability to recognize objects depends on prior experience [figure from Altavini et al, 2025; text adapted from Report from The Rockefeller University]

New findings on object recognition from the lab of Charles D. Gilbert show that neurons in early visual cortex are selective for much more complex stimuli than had previously been believed, and that capability is informed by feedback from higher cortical areas.