Biology subjects

Throm, B.

Publications and source records attributed to Throm, B..

3 recordsLinked to original sources

bioRxiv2026

Prior experience dynamically determines differential cue weighting in the medial entorhinal cortex

Spatial navigation depends on integrating multiple cue sets whose influence is determined primarily by their inferred reliability. Here we investigated how cue weighting in the medial entorhinal cortex is updated based on previous experience at different time scales (minutes vs. days). In mice recorded in light and darkness while manipulating coherence between distal room cues and local arena cues, grid cells displayed stable firing fields in darkness only when prior light experience maintained coherent cue relationships. Grid activity remained anchored to local cues, and stability continuously increased by repeated exposure. In contrast, mice that experienced cue mismatch in light showed markedly reduced grid stability in darkness. Strikingly, re-establishing cue coherence produced only partial recovery, whereas a single exposure to cue mismatch abolished reliance on local cues. The reference frame shift at different time scales reflects a dynamic balance between flexibility and stability determined by a conservative cue weighting strategy.

neuroscience↗

bioRxiv2026

Shared early impairments of medial entorhinal cortex function across distinct Alzheimer's disease etiologies

The medial entorhinal cortex (MEC) harbors diverse spatially and object-tuned cell types essential for spatial coding and episodic memory, and is among the earliest regions affected in neurodegenerative diseases. Here, we examined how early neurodegeneration alters MEC cellular coding, network dynamics, and behavior in two Alzheimer mouse models of distinct etiology. Specifically, we performed in vivo electrophysiology, immunohistochemistry and behavioral assays in models that reflect the manifestation of a tauopathy and amyloidopathy, respectively, to identify common impairments. In both models, the earliest deficits manifested as instability of spatial context representations at the cellular and behavioral level. These impairments preceded model-specific disruptions in grid cell coding and altered theta oscillations. We further identified reduced parvalbumin-positive (PV+) septal projections as a likely contributor to MEC dysfunction. In contrast, object-vector coding remained intact, highlighting spatial context instability as an early marker of MEC impairment.

neuroscience↗

bioRxiv2023

Grid cells perform path integration in multiple reference frames during self-motion-based navigation

With their periodic firing pattern, grid cells are considered a fundamental unit of a neural network performing path integration. The periodic firing patterns of grid cells have been observed mainly during behaviors with little navigational demands, and the firing patterns of grid cells in animals navigating 2D environments using path integration are largely unknown. Here, we recorded the activity of grid cells in mice performing the AutoPI task, a task assessing homing based on path integration. Using artificial deep neural networks to decode the animals moment-to-moment movement vectors, we found that grid cells perform path integration over short trajectories and change their reference frames within single trials. More specifically, grid cell modules re-anchor to a task-relevant object via a translation of the grid pattern. The code for movement direction in grid modules drifts as the animal navigates using self-motion cues, and this drift predicts the homing direction of the mouse. These results reveal the computations in grid cell circuits during self-motion-based navigation.

neuroscience↗