Behavioural Repertoire
behavioural repertoire
Brain-Wide Compositionality and Learning Dynamics in Biological Agents
Biological agents continually reconcile the internal states of their brain circuits with incoming sensory and environmental evidence to evaluate when and how to act. The brains of biological agents, including animals and humans, exploit many evolutionary innovations, chiefly modularity—observable at the level of anatomically-defined brain regions, cortical layers, and cell types among others—that can be repurposed in a compositional manner to endow the animal with a highly flexible behavioral repertoire. Accordingly, their behaviors show their own modularity, yet such behavioral modules seldom correspond directly to traditional notions of modularity in brains. It remains unclear how to link neural and behavioral modularity in a compositional manner. We propose a comprehensive framework—compositional modes—to identify overarching compositionality spanning specialized submodules, such as brain regions. Our framework directly links the behavioral repertoire with distributed patterns of population activity, brain-wide, at multiple concurrent spatial and temporal scales. Using whole-brain recordings of zebrafish brains, we introduce an unsupervised pipeline based on neural network models, constrained by biological data, to reveal highly conserved compositional modes across individuals despite the naturalistic (spontaneous or task-independent) nature of their behaviors. These modes provided a scaffolding for other modes that account for the idiosyncratic behavior of each fish. We then demonstrate experimentally that compositional modes can be manipulated in a consistent manner by behavioral and pharmacological perturbations. Our results demonstrate that even natural behavior in different individuals can be decomposed and understood using a relatively small number of neurobehavioral modules—the compositional modes—and elucidate a compositional neural basis of behavior. This approach aligns with recent progress in understanding how reasoning capabilities and internal representational structures develop over the course of learning or training, offering insights into the modularity and flexibility in artificial and biological agents.
Orbitofrontal cortex and the integrative approach to functional neuroanatomy
The project of functional neuroanatomy typically considers single brain areas as the core functional unit of the brain. Functional neuroanatomists typically use specialized tasks that are designed to isolate hypothesized functions from other cognitive processes. Our lab takes a broader view; specifically, we consider brain regions as parts of larger circuits and we take cognitive processes as part of more complex behavioral repertoires. In my talk, I will discuss the ramifications of this perspective for thinking about the role of the orbitofrontal cortex. I will discuss results of recent experiments from my lab that tackle the question of OFC function within the context of larger brain networks and in freely moving foraging tasks. I will argue that this perspective challenges conventional accounts of the role of OFC and invites new ones. I will conclude by speculating on implications for the practice of functional neuroanatomy.