Retro-prospective representations and communication subspaces of the cognitive map
Creators: name: Young, Ryan A
Publisher: name: Brandeis University
Year: 2024
Subjects: Cognitive Map
Communication Subspaces
Goal-coding
Hippocampus
Prefrontal Cortex
Temporal Coding

description: Representational states of our world are woven together into a tapestry of connected statescalled the cognitive map (CM) — a model of our external world (Tolman, 1948). Historically,
description: investigations have focused on CM states representing the current, immediate features in the
description: animal’s environment4. But in the past few decades, work has endeavored to extend this
description: understanding of the map in two directions—(1) how does the CM represent previous and
description: upcoming states needed to both contextualize present states in the past and to flexibly
description: plan upcoming states. This is known to involve both sequences of CM cells stretching
description: ahead/behind the animal (Skaggs &amp; McNaughton, 1996) and recently, cells that incorporate
description: the past or future in their receptive field (Ferbinteanu &amp; Shapiro, 2003; Frank, Brown, &amp;
description: Wilson, 2000; Howard et al., 2014; Sarel et al., 2017; Wood et al., 2000). (2) how does the
description: cognitive map emerge from multi-brain area communication and dialogue?
description: In this work, we attempt to study both questions above using two brain areas, the hip-pocampus and prefrontal cortex, key players in memory-guided navigation (Floresco, Sea-
description: mans, &amp; Phillips, 1997; Maharjan et al., 2018). We looked for cells that represent upcoming
description: states (goals and spaces; Chapters 2 &amp; 3) or the past (Chapter 3). And we attempted to
description: study how these areas might cooperate through communication subspaces to empower the
description: emergent cognitive map (Chapter 4).
description: The first study (Chapter 2) focuses on representations of future, namely goal states(Ormond &amp; O’Keefe, 2022; Sarel et al., 2017). It examines hippocampal and prefrontal
description: 4i.e. percepts as transformed information streaming from the sensorium—the spinal cord and cranial
description: nerves; additionally, transformed features may be inclusive of the animal’s action/motorium states.
description: neuronal populations during a spatial memory task, decoding goal information and locationswith a convolutional neural network. This analysis highlights robust goal decoding facilitated
description: by CA1 and PFC activity, with a nuanced observation that place encoding predominates over
description: goal coding in these regions.
description: The second study (Chapter 3) delves into spatiotemporal coding in CA1-PFC place cells(Dotson &amp; Yartsev, 2021), revealing some place cells preferably represent past and future
description: space in rats. Critically we find modulation of non-local temporal fields between cue-guided
description: and memory-guided conditions, underscoring a possible influence of task demands on tem-
description: poral coding.
description: We lastly examine communication. Chapter 4 investigates how hippocampal-prefrontalcommunication subspaces (CS) might support memory-guided behavior and to what extent
description: prior communication-driven network patterns influence CS (Semedo et al., 2019). It demon-
description: strates that aligned subspace activity is a strong predictor of task outcomes, contrasting with
description: the ineffectiveness of orthogonal activity. Further, the study discerns how different rhythms,
description: notably theta and ripples, uniquely influence subspace dimensionality and performance. The
description: alignment of communication with theta rhythm amplitude exhibits a progressive adaptation
description: over learning epochs, illuminating complex dynamics in cross-regional interactions during
description: spatial memory tasks.
description: Collectively, these studies help form a picture of the dynamics of retro-prospective infor-mation, how they differ with task demands, and how rhythms shape communication-related
description: spiking subserving this CM system and the downstream behavior.