Biology subjects

Kloosterman, F.

Publications and source records attributed to Kloosterman, F..

8 recordsLinked to original sources

bioRxiv2025

Specific anterior-posterior brain-wide input patterns support specialized visuospatial processing in the mouse retrosplenial cortex

The retrosplenial cortex (RSC) is a key integrative hub involved in spatial orientation, navigation, and cognitive processes. In rodents, RSC neurons carry rich sensory and navigational signals and are interconnected with sensory, motor, thalamic, and hippocampal circuits--supporting multimodal integration. However, the circuitry that supports this integration remain unclear. Here, we combined 2-photon calcium imaging in navigating mice with brain-wide retrograde tracing to investigate how visual and positional information are represented and distributed across RSC subregions. We found a clear anterior-posterior gradient: anterior RSC neurons exhibited sharper, more reliable position tuning and preferred fast-moving visual stimuli, while posterior RSC neurons showed broader tuning and preferential responses to slower motion. These functional differences were paralleled by distinct patterns of long-range input: anterior RSC received denser projections from motor, parietal, and hippocampal-associated areas--regions implicated in position encoding--whereas posterior RSC was more strongly innervated by visual cortices. Our findings reveal that the RSC contains functionally and anatomically distinct subregions specialized for processing different visuospatial features, suggesting a modular organization that supports integration of contextual and sensory information during navigation.

neuroscience↗

bioRxiv2024

Neurons in the medial prefrontal cortex that are not modulated by hippocampal sharp-wave ripples are involved in spatial tuning and signaling upcoming choice.

The hippocampus is known to encode spatial information and reactivate experienced trajectories during sharp-wave ripple events. These events are thought to be key time-points at which information about learned trajectories is transferred to the neocortex for long-term storage. It is unclear, however, how this information may be transferred and integrated in downstream cortical regions. In this study, we performed high-density probe recordings across the full depth of the medial prefrontal cortex and in the hippocampus simultaneously in rats while they were performing a task of spatial navigation. We find that neurons in the medial prefrontal cortex encode spatial information and reliably predict upcoming choice on a maze, and we find that a subset of neurons in the mPFC is modulated by hippocampal sharp-wave ripples. However, sharp-wave ripple modulation does not appear to be the main driving factor in predicting upcoming choice. This indicates that the integration of spatial information requires the collaboration of different specialized populations of neurons.

neuroscience↗

bioRxiv2023

Theta cycle dynamics of spatial representations in the lateral septum

An internal representation of the environment - or map - allows animals to evaluate multiple routes and adapt their navigation strategy to current needs and future goals. The hippocampal formation plays a crucial role in learning a spatial map and using the map for goal-directed navigation. The lateral septum forms a major node for connections between the hippocampus and subcortical brain regions that could link the spatial map to motivation and reward processing centers such as the ventral tegmental area and hypothalamus. It is not known, however, how the lateral septum contributes to the processing of spatial information and route planning. In this study, we investigated the temporal dynamics of spatial representations in the lateral septum. Neuropixels probes were used to record cellular activity along the dorsal-ventral extent of the lateral septum while rats performed one of two spatial navigation tasks in a Y-maze. The activity of a large fraction of cells was theta rhythmic and a subset of cells showed evidence of being active on alternate theta cycles (theta cycle skipping). Both theta rhythmicity and cycle skipping were strongest in the dorsal lateral septum. Similarly, spatially selective firing was most prominent in the dorsal lateral septum. Using neural decoding, we show that the lateral septum cell population encodes both the current location and alternatingly the possible future paths within single theta cycles when rats approach the choice point in the maze. Our data further shows that the alternating expression of spatial representations in the lateral septum is task-dependent, such that it is strongest when the task also requires the animals to alternate between rewarded goal arms. These data suggest that task demands and experience shape which representations are activated near a choice point. The lateral septum receives strong input from hippocampal place cells, and while there may be integration and transformation of incoming spatial signals, our findings support the idea that hippocampal spatial representations and their temporal dynamics are conveyed to subcortical projection areas through the lateral septum.

neuroscience↗

bioRxiv2022

Awake hippocampal replay is not required for short-term memory

Short-term memory (STM) on a time scale of seconds to minutes is required to successfully perform day-to-day tasks, for example when engaging in a meaningful conversation. Previous studies in both rodents and primates have correlated hippocampal cellular activity and behavioural expression of STM. This research has led to models describing the putative neural mechanism in the hippocampus that mediate STM. In these models, a key role has been given to hippocampal replay - reactivation of neurons representing a trajectory through space- but definitive causal evidence that can challenge or confirm the model is missing. In this study, we aimed to address the uncertainty around the role of awake replay in STM by collecting direct causal evidence from behaving rats. Signatures of replay events were detected in the hippocampus and disrupted using electrical stimulation of the ventral hippocampal commissure in rats that were trained on three different spatial memory tasks in a multi-arm radial maze. All tasks required memory of the recent past, but varied in the time scale over which information needed to be retained: (1) a multiple trial match-to sample task, (2) a single trial non-match to sample task and (3) a spatial sequence memory paradigm. Rats readily learned the task rules, but disruption of awake replay did not affect task performance or other behavioral measures in any of the task. Altogether, our results show for the first time with definitive causal evidence that awake replay is not required for STM of events or of their temporal order.

neuroscience↗

bioRxiv2022

Sharp-wave ripple associated activity in the medial prefrontal cortex supports spatial rule switching

Previous studies have highlighted an important role for hippocampal sharp-wave ripples in spatial alternation learning, as well as modulating activity in the medial prefrontal cortex (mPFC). However, no study so far has investigated the direct influence of hippocampal sharp-wave ripples on mPFC activity during spatial alternation learning. Long Evans rats were trained on a three-arm radial maze to perform a sequence of alternations. Three different alternation sequences needed to be learnt, and while learning a new sequence, the activity in the mPFC was inhibited either directly following sharp-wave ripples in the hippocampus (on-time condition) or with a randomized delay (delayed condition). In the on-time condition the behavioral performance was significantly worse compared to the same animals in the delayed inhibition condition, as measured by a lower correct alternation performance and more perseverative behavior. This indicates that the activity in the mPFC directly following hippocampal sharp-wave ripples is necessary for spatial rule switching.

neuroscience↗

bioRxiv2020

Single-trial dynamics of hippocampal spatial representations are modulated by reward value

Reward value is known to modulate learning speed in spatial memory tasks, but little is known about its influence on the dynamical changes in hippocampal spatial representations. Here, we monitored the trial-to-trial changes in hippocampal place cell activity during the acquisition of place-reward associations with varying reward size. We show a faster reorganization and stabilization of the hippocampal place map when a goal location is associated with a large reward. The reorganization is driven by both rate changes and the appearance and disappearance of place fields. The occurrence of hippocampal replay activity largely followed the dynamics of changes in spatial representations. Replay patterns became more selectively tuned towards behaviorally relevant experiences over the course of learning. These results suggests that high reward value enhances memory retention via accelerating the formation and stabilization of the hippocampal cognitive map and enhancing its reactivation during learning.

neuroscience↗

bioRxiv2020

A Dual Reward-Place Association Task to Study the Preferential Retention of relevant Memories in Rats

Memories of past events and common knowledge are critical to flexibly adjust ones future behavior based on prior experiences. The formation and the transformation of these memories into a long-lasting form are supported by a dialog between the coordinated activity of population of neurons in the cortex and the hippocampus. Not all experiences are remembered equally well nor for equally long. It has been demonstrated experimentally in humans that memory strength positively depends on the behavioral relevance of the associated experience. Behavioral paradigms testing the selective retention of memory in rodents would enable to further investigate the neuronal mechanisms at play. We developed a novel paradigm to follow the repeated acquisition and retrieval of two contextually distinct, yet concurrently occurring, food-place associations in rats. We demonstrated the use of this paradigm by varying the amount of reward associated with the two locations. After delays of 2h or 20h, rats showed better memory performance for experiences associated with larger amount of reward. This effect depends on the level of spatial integration required to retrieve the associated location. Thus, this paradigm is suited to study the preferential retention of relevant experiences in rats.

animal behavior and cognition↗

bioRxiv2019

SHYBRID: A graphical tool for generating hybrid ground-truth spiking data for evaluating spike sorting performance

Spike sorting is the process of retrieving the spike times of individual neurons that are present in an extracellular neural recording. Over the last decades, many spike sorting algorithms have been published. In an effort to guide a user towards a specific spike sorting algorithm, given a specific recording setting (i.e., brain region and recording device), we provide an open-source graphical tool for the generation of hybrid ground-truth data in Python. Hybrid ground-truth data is a data-driven modelling paradigm in which spikes from a single unit are moved to a different location on the recording probe, thereby generating a virtual unit of which the spike times are known. The tool enables a user to efficiently generate hybrid ground-truth datasets and make informed decisions between spike sorting algorithms, fine-tune the algorithm parameters towards the used recording setting, or get a deeper understanding of those algorithms.

neuroscience↗