Biology subjects

Nitz, D. A.

Publications and source records attributed to Nitz, D. A..

7 recordsLinked to original sources

bioRxiv2025

Neural Mechanisms Linking Global Maps to First-Person Perspectives

Humans and many animals possess the remarkable ability to navigate environments by seamlessly switching between first-person perspectives (FPP) and global map perspectives (GMP). However, the neural mechanisms that underlie this transformation remain poorly understood. In this study, we developed a variational autoencoder (VAE) model, enhanced with recurrent neural networks (RNNs), to investigate the computational principles behind perspective transformations. Our results reveal that temporal sequence modeling is crucial for maintaining spatial continuity and improving transformation accuracy when switching between FPPs and GMPs. The models latent variables capture many representational forms seen in the distributed cognitive maps of the mammalian brain, such as head direction cells, place cells, corner cells, and border cells, but notably not grid cells, suggesting that perspective transformation engages multiple brain regions beyond the hippocampus and entorhinal cortex. Furthermore, our findings demonstrate that landmark encoding, particularly proximal environmental cues such as boundaries and objects, play a critical role in enabling successful perspective shifts, whereas distal cues are less influential. These insights on perspective linking provide a new computational framework for understanding spatial cognition and offer valuable directions for future animal and human studies, highlighting the significance of temporal sequences, distributed representations, and proximal cues in navigating complex environments. Significance StatementUnderstanding how the brain transforms between different spatial perspectives is crucial for advancing our knowledge of spatial cognition and navigation. This study presents a novel computational approach that bridges the gap between neural recordings and behavior, offering insights into the underlying mechanisms of perspective transformation. Our findings suggest how the brain integrates temporal sequences, distributed representations, and environmental cues to maintain a coherent sense of space. By demonstrating the importance of proximal cues and temporal context, our computational model provides testable predictions for future neurophysiological studies in humans and animals.

neuroscience↗

bioRxiv2024

Posterior parietal cortex maps progress along routes sharing the same meta-structure

Neurons of posterior parietal cortex were recorded as rats performed a working memory task within a network of intersecting paths. The specific routes utilized in task performance provided opportunity to contrast responses of posterior parietal cortex sub-populations to linear and angular velocity with more complex responses that map route progress. We found evidence for the presence of posterior parietal cortex neurons that generalize in their firing patterns across routes having the same shape but opposite action series. The results indicate that posterior parietal cortex has the capacity to generalize the mapping of route progress independent of the specific actions taken to move through those routes. We suggest that such encoding can form the basis for learning the meta-structural organization of a non-random path network structure, such as that commonly found in cities.

neuroscience↗

bioRxiv2023

The subiculum encodes environmental geometry

Corners are a cardinal feature of many of the complex environmental geometries found in the natural world but the neural substrates that could underlie the perception of corners remain elusive. Here we show that the dorsal subiculum contains neurons that encode corners across environmental geometries in an allocentric reference frame. Corner cells changed their activity to reflect concave corner angles, wall height and the degree of wall intersection. A separate population of subicular neurons encoded convex corners. Both concave and convex corner cells were non-overlapping with subicular neurons that encoded environmental boundaries, suggesting that the subiculum contains the geometric information needed to re-construct the shape and layout of naturalistic spatial environments. One Sentence SummarySeparate neural populations in the subiculum encode concave and convex environmental corners.

neuroscience↗

bioRxiv2021

Complementary Maps for Location and Environmental Structure in CA1 and Subiculum

The dorsal subiculum lies among a network of interconnected brain regions that collectively map multiple spatial and orientational relationships between an organism and the boundaries and pathways composing its environment. A unique role of the subiculum in spatial information processing has yet to be defined despite reports of small neuron subpopulations that encode relationships to specific boundaries, axes of travel, or locations. We examined the activity patterns among populations of subiculum neurons during performance of a spatial working memory task performed within a complex network of interconnected pathways. Compared to neurons in hippocampal sub-region CA1, a major source of its afferents, subiculum neurons were far more likely to exhibit multiple firing fields at locations that were analogous with respect to path structure and function. Subiculum neuron populations were also found to exhibit a greater dynamic range in scale of spatial representation and for persistent patterns of spiking activity to be aligned to transitions between maze segments. Together, the findings indicate that the subiculum plays a unique role in spatial mapping, one that complements the location-specific firing of CA1 neurons with the encoding of emergent and recurring structural features of a complex path network.

neuroscience↗

bioRxiv2020

Adaptive integration of self-motion and goals in posterior parietal cortex

Animals engage in a variety of navigational behaviors that require different regimes of behavioral control. In the wild, rats readily switch between foraging and more complex behaviors such as chase, wherein they pursue other rats or small prey. These tasks require vastly different tracking of multiple behaviorally-significant variables including self-motion state. It is unknown whether changes in navigational context flexibly modulate the encoding of these variables. To explore this possibility, we compared self-motion processing in the multisensory posterior parietal cortex while rats performed alternating blocks of free foraging and visual target pursuit. Animals performed the pursuit task and demonstrated predictive processing by anticipating target trajectories and intercepting them. Relative to free exploration, pursuit sessions yielded greater proportions of parietal cortex neurons with reliable sensitivity to self-motion. Multiplicative gain modulation was observed during pursuit which increased the dynamic range of tuning and led to enhanced decoding accuracy of self-motion state. We found that self-motion sensitivity in parietal cortex was history-dependent regardless of behavioral context but that the temporal window of self-motion tracking was extended during target pursuit. Finally, many self-motion sensitive neurons conjunctively tracked the position of the visual target relative to the animal in egocentric coordinates, thus providing a potential coding mechanism for the observed gain changes to self-motion signals. We conclude that posterior parietal cortex dynamically integrates behaviorally-relevant information in response to ongoing task demands.

neuroscience↗

bioRxiv2019

Secondary Motor Cortex Transforms Spatial Information into Planned Action During Navigation

Fluid navigation requires constant updating of planned movements to adapt to evolving obstacles and goals. A neural substrate for navigation demands spatial and environmental information and the ability to effect actions through efferents. Secondary motor cortex is a prime candidate for this role given its interconnectivity with association cortices that encode spatial relationships and its projection to primary motor cortex. Here we report that secondary motor cortex neurons robustly encode both planned and current left/right turning actions across multiple turn locations in a multi-route navigational task. Comparisons within a common statistical framework reveal that secondary motor cortex neurons differentiate contextual factors including environmental position, route, action sequence, orientation, and choice availability. Despite significant modulation by context, action planning and execution are the dominant output signals of secondary motor cortex neurons. These results identify secondary motor cortex as a structure integrating environmental context toward the updating of planned movements.

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bioRxiv2017

Spatially periodic activation patterns of retrosplenial cortex encode route sub-spaces and distance travelled

Traversal of a complicated route is often facilitated by considering it as a set of related sub-spaces. Such compartmentalization processes could occur within retrosplenial cortex, a structure whose neurons simultaneously encode position within routes and other spatial coordinate systems. Here, retrosplenial cortex neurons were recorded as rats traversed a track having recurrent structure at multiple scales. Consistent with a major role in compartmentalization of complex routes, individual RSC neurons exhibited periodic activation patterns that repeated across route segments having the same shape. Concurrently, a larger population of RSC neurons exhibited single-cycle periodicity over the full route, effectively defining a framework for encoding of sub-route positions relative to the whole. The same population simultaneously provides a novel metric for distance from each route position to all others. Together, the findings implicate retrosplenial cortex in the extraction of path sub-spaces, the encoding of their spatial relationships to each other, and path integration.

neuroscience↗