Evolution of neural activity in circuits bridging sensory and abstract knowledge

Abstract

The ability to associate sensory stimuli with abstract classes is critical for survival. How are these associations implemented in brain circuits? And what governs how neural activity evolves during abstract knowledge acquisition? To investigate these questions, we consider a circuit model that learns to map sensory inputs into abstract classes via gradient descent synaptic plasticity. We focus on typical neuroscience tasks (simple, and context-dependent, categorization), and study how both synaptic connectivity and neural activity evolve during learning. To make contact with the current generation of experiments we focus on the latter, and analyze activity via standard measures such as selectivity, correlations, and tuning symmetry. We find that the model is able to capture experimental observations, including seemingly disparate ones. We determine how, in the model, the behaviour of these activity measures depends on details of the circuit and the task. These dependencies make experimentally-testable predictions about the circuitry supporting abstract knowledge acquisition in the brain.