scholarly journals Persistent trajectory-modulated hippocampal neurons support memory-guided navigation

2019 ◽  
Author(s):  
Nathaniel R. Kinsky ◽  
William Mau ◽  
David W. Sullivan ◽  
Samuel J. Levy ◽  
Evan A. Ruesch ◽  
...  
Keyword(s):  
Calcium Imaging ◽  
Hippocampal Neurons ◽  
Spatial Information ◽  
Single Photon ◽  
Place Cells ◽  
Dependent Activity ◽  
Freely Moving ◽  
Stable Trajectory ◽  
Alternation Task

ABSTRACTTrajectory-dependent splitter neurons in the hippocampus encode information about a rodent’s prior trajectory during performance of a continuous alternation task. As such, they provide valuable information for supporting memory-guided behavior. Here, we employed single-photon calcium imaging in freely moving mice to investigate the emergence and fate of trajectory-dependent activity through learning and mastery of a continuous spatial alternation task. We found that the quality of trajectory-dependent information in hippocampal neurons correlated with task performance. We thus hypothesized that, due to their utility, splitter neurons would exhibit heightened stability. We found that splitter neurons were more likely to remain active and retained more consistent spatial information across multiple days than did place cells. Furthermore, we found that both splitter neurons and place cells emerged rapidly and maintained stable trajectory-dependent/spatial activity thereafter. Our results suggest that neurons with useful functional coding properties exhibit heightened stability to support memory guided behavior.

scholarly journals Efficient neural decoding of self-location with a deep recurrent network

2018 ◽  
Author(s):  
Ardi Tampuu ◽  
Tambet Matiisen ◽  
H. Freyja Ólafsdóttir ◽  
Caswell Barry ◽  
Raul Vicente
Keyword(s):  
Hippocampal Neurons ◽  
Cell Activity ◽  
Recurrent Network ◽  
Brain Network ◽  
Place Cells ◽  
Neuronal Firing ◽  
Temporal Context ◽  
Central Component ◽  
Neural Decoding ◽  
Freely Moving

AbstractPlace cells in the mammalian hippocampus signal self-location with sparse spatially stable firing fields. Based on observation of place cell activity it is possible to accurately decode an animal’s location. The precision of this decoding sets a lower bound for the amount of information that the hippocampal population conveys about the location of the animal. In this work we use a novel recurrent neural network (RNN) decoder to infer the location of freely moving rats from single unit hippocampal recordings. RNNs are biologically plausible models of neural circuits that learn to incorporate relevant temporal context without the need to make complicated assumptions about the use of prior information to predict the current state. When decoding animal position from spike counts in 1D and 2D-environments, we show that the RNN consistently outperforms a standard Bayesian model with flat priors. In addition, we also conducted a set of sensitivity analysis on the RNN decoder to determine which neurons and sections of firing fields were the most influential. We found that the application of RNNs to neural data allowed flexible integration of temporal context, yielding improved accuracy relative to a commonly used Bayesian approach and opens new avenues for exploration of the neural code.Author summaryBeing able to accurately self-localize is critical for most motile organisms. In mammals, place cells in the hippocampus appear to be a central component of the brain network responsible for this ability. In this work we recorded the activity of a population of hippocampal neurons from freely moving rodents and carried out neural decoding to determine the animals’ locations. We found that a machine learning approach using recurrent neural networks (RNNs) allowed us to predict the rodents’ true positions more accurately than a standard Bayesian method with flat priors. The RNNs are able to take into account past neural activity without making assumptions about the statistics of neuronal firing. Further, by analyzing the representations learned by the network we were able to determine which neurons, and which aspects of their activity, contributed most strongly to the accurate decoding.

scholarly journals Place cells in head-fixed mice navigating a floating real-world environment

2020 ◽  
Author(s):  
Mary Ann Go ◽  
Jake Rogers ◽  
Giuseppe P. Gava ◽  
Catherine Davey ◽  
Seigfred Prado ◽  
...  
Keyword(s):  
Virtual Reality ◽  
Real World ◽  
Spatial Information ◽  
Memory Function ◽  
Place Cells ◽  
Neural Population ◽  
Spatial Coding ◽  
Place Fields ◽  
Freely Moving ◽  
World Environment

ABSTRACTThe hippocampal place cell system in rodents has provided a major paradigm for the scientific investigation of memory function and dysfunction. Place cells have been observed in area CA1 of the hippocampus of both freely moving animals, and of head-fixed animals navigating in virtual reality environments. However, spatial coding in virtual reality preparations has been observed to be impaired. Here we show that the use of a real-world environment system for head-fixed mice, consisting of a track floating on air, provides some advantages over virtual reality systems for the study of spatial memory. We imaged the hippocampus of head-fixed mice injected with the genetically encoded calcium indicator GCaMP6s while they navigated circularly constrained or open environments on the floating platform. We observed consistent place tuning in a substantial fraction of cells with place fields remapping when animals entered a different environment. When animals re-entered the same environment, place fields typically remapped over a time period of multiple days, faster than in freely moving preparations, but comparable with virtual reality. Spatial information rates were within the range observed in freely moving mice. Manifold analysis indicated that spatial information could be extracted from a low-dimensional subspace of the neural population dynamics. This is the first demonstration of place cells in head-fixed mice navigating on an air-lifted real-world platform, validating its use for the study of brain circuits involved in memory and affected by neurodegenerative disorders.

scholarly journals Place Cells in Head-Fixed Mice Navigating a Floating Real-World Environment

2021 ◽  
Vol 15 ◽  
Author(s):  
Mary Ann Go ◽  
Jake Rogers ◽  
Giuseppe P. Gava ◽  
Catherine E. Davey ◽  
Seigfred Prado ◽  
...  
Keyword(s):  
Virtual Reality ◽  
Real World ◽  
Spatial Information ◽  
Memory Function ◽  
Place Cells ◽  
Neural Population ◽  
Spatial Coding ◽  
Place Fields ◽  
Freely Moving ◽  
World Environment

The hippocampal place cell system in rodents has provided a major paradigm for the scientific investigation of memory function and dysfunction. Place cells have been observed in area CA1 of the hippocampus of both freely moving animals, and of head-fixed animals navigating in virtual reality environments. However, spatial coding in virtual reality preparations has been observed to be impaired. Here we show that the use of a real-world environment system for head-fixed mice, consisting of an air-floating track with proximal cues, provides some advantages over virtual reality systems for the study of spatial memory. We imaged the hippocampus of head-fixed mice injected with the genetically encoded calcium indicator GCaMP6s while they navigated circularly constrained or open environments on the floating platform. We observed consistent place tuning in a substantial fraction of cells despite the absence of distal visual cues. Place fields remapped when animals entered a different environment. When animals re-entered the same environment, place fields typically remapped over a time period of multiple days, faster than in freely moving preparations, but comparable with virtual reality. Spatial information rates were within the range observed in freely moving mice. Manifold analysis indicated that spatial information could be extracted from a low-dimensional subspace of the neural population dynamics. This is the first demonstration of place cells in head-fixed mice navigating on an air-lifted real-world platform, validating its use for the study of brain circuits involved in memory and affected by neurodegenerative disorders.

scholarly journals Scopolamine Impairs Spatial Information Recorded With “Miniscope” Calcium Imaging in Hippocampal Place Cells

2021 ◽  
Vol 15 ◽  
Author(s):  
Dechuan Sun ◽  
Ranjith Rajasekharan Unnithan ◽  
Chris French
Keyword(s):  
Spatial Memory ◽  
Calcium Imaging ◽  
Memory Retrieval ◽  
Spatial Information ◽  
Place Cells ◽  
Network Activity ◽  
Memory Encoding ◽  
Neural Firing ◽  
Neural Ensemble ◽  
Hippocampal Network

The hippocampus and associated cholinergic inputs have important roles in spatial memory in rodents. Muscarinic acetylcholine receptors (mAChRs) are involved in the communication of cholinergic signals and regulate spatial memory. They have been found to impact the memory encoding process, but the effect on memory retrieval is controversial. Previous studies report that scopolamine (a non-selective antagonist of mAChR) induces cognitive deficits on animals, resulting in impaired memory encoding, but the effect on memory retrieval is less certain. We tested the effects of blocking mAChRs on hippocampal network activity and neural ensembles that had previously encoded spatial information. The activity of hundreds of neurons in mouse hippocampal CA1 was recorded using calcium imaging with a miniaturised fluorescent microscope and properties of place cells and neuronal ensemble behaviour in a linear track environment were observed. We found that the decoding accuracy and the stability of spatial representation revealed by hippocampal neural ensemble were significantly reduced after the administration of scopolamine. Several other parameters, including neural firing rate, total number of active neurons, place cell number and spatial information content were affected. Similar results were also observed in a simulated hippocampal network model. This study enhances the understanding of the function of mAChRs on spatial memory impairment.

scholarly journals Different encoding of reward location in dorsal and ventral hippocampus

2021 ◽  
Author(s):  
Przemyslaw Jarzebowski ◽  
Y. Audrey Hay ◽  
Benjamin F. Grewe ◽  
Ole Paulsen
Keyword(s):  
Calcium Imaging ◽  
Hippocampal Neurons ◽  
Dorsal Hippocampus ◽  
Spatial Navigation ◽  
Ventral Hippocampus ◽  
Place Cells ◽  
Cognitive Map ◽  
Population Activity ◽  
Reward Seeking ◽  
Seeking Behavior

SummaryHippocampal neurons encode a cognitive map for spatial navigation1. When they fire at specific locations in the environment, they are known as place cells2. In the dorsal hippocampus place cells accumulate at current navigational goals, such as learned reward locations3–6. In the intermediate-to-ventral hippocampus (here collectively referred to as ventral hippocampus), neurons fire across larger place fields7–10 and regulate reward- seeking behavior11–16, but little is known about their involvement in reward-directed navigation. Here, we compared the encoding of learned reward locations in the dorsal and ventral hippocampus during spatial navigation. We used calcium imaging with a head- mounted microscope to track the activity of CA1 cells over multiple days during which mice learned different reward locations. In dorsal CA1 (dCA1), the overall number of active place cells increased in anticipation of reward but the recruited cells changed with the reward location. In ventral CA1 (vCA1), the activity of the same cells anticipated the reward locations. Our results support a model in which the dCA1 cognitive map incorporates a changing population of cells to encode reward proximity through increased population activity, while the vCA1 provides a reward-predictive code in the activity of a specific subpopulation of cells. Both of these location-invariant codes persisted over time, and together they provide a dual hippocampal reward-location code, assisting goal- directed navigation17, 18.

scholarly journals In Vivo Multi-Day Calcium Imaging of CA1 Hippocampus in Freely Moving Rats Reveals a High Preponderance of Place Cells and No Detectable Photobleaching

2021 ◽  
Author(s):  
Hannah S Wirtshafter ◽  
John F Disterhoft
Keyword(s):  
Calcium Imaging ◽  
Place Cells ◽  
Freely Moving Rats ◽  
Calcium Indicators ◽  
Large Populations ◽  
Freely Moving ◽  
Cell Changes ◽  
Long Timescales ◽  
In Vivo Calcium Imaging

Calcium imaging using GCaMP calcium indicators and miniature microscopes has been used to image cellular populations during long timescales and in different task phases, as well as to determine neuronal circuit topology and organization. Because the hippocampus (HPC) is essential for many tasks of memory, spatial navigation, and learning, calcium imaging of large populations of HPC neurons can provide new insight on cell changes and organization over time during these tasks. To our knowledge, all reported HPC in vivo calcium imaging experiments have been done in mouse. However, rats have many behavioral and physiological experimental advantages over mice, and, due to their larger size, rats are able to support larger implants, thereby enabling the recording of a greater number of cells. In this paper, we present the first in vivo calcium imaging from CA1 hippocampus in freely moving rats. Using GCaMP7c and the UCLA Miniscope, we demonstrate that hundreds of cells (mean 240+-90 cells per session, maximum 428 cells) can reliably be visualized and held across weeks, and that calcium events in these cells are correlated with periods of movement. We additionally show proof of method by showing that an extremely high percent of place cells (82.3%+-8.1%, far surpassing the percent seen during mouse calcium imaging) can be recorded on a navigational task, and that these place cells enable accurately decoding of animal position. Finally, we show that calcium imaging is rats is not prone to photobleaching during hour-long recordings and that cells can be reliably recorded for an hour or more per session. A detailed protocol for this technique, including notes on the numerous parameter changes needed to use Ca2+ in rats, is included in the Materials and Methods section, and implications of these advancements are discussed.

scholarly journals Observations of the Effect of Scopolamine on Hippocampal CA1 Place Cell and Network Properties in Freely Moving Mice Using Miniscope Imaging

2020 ◽  
Author(s):  
Dechuan Sun ◽  
Ranjith Rajasekharan Unnithan ◽  
Chris French
Keyword(s):  
Spatial Memory ◽  
Calcium Imaging ◽  
Memory Retrieval ◽  
Spatial Information ◽  
Place Cell ◽  
Memory Encoding ◽  
Hippocampal Ca1 ◽  
Network Properties ◽  
Freely Moving ◽  
Decoding Accuracy

AbstractThe hippocampus and associated cholinergic inputs regulate spatial memory in rodents. Muscarinic blockade with scopolamine results in cognition deficits usually attributed to impaired memory encoding, but effects on memory retrieval are controversial. Here, we simultaneously recorded hundreds of neurons in mouse hippocampal CA1 using calcium imaging with a miniatured fluorescent microscope to study place cell and ensemble neuronal properties in a linear track environment. We found decoding accuracy and ensemble stability were significantly reduced after the administration of scopolamine. Several other parameters including the Ca2+ event rate, number of total cells and place cells observed, spatial information content were affected including a small increase in running speed. This study enhances the understanding of cholinergic blockade on spatial memory impairment.

scholarly journals DNA repair enzyme NEIL3 enables a stable neural representation of space by shaping transcription in hippocampal neurons

2021 ◽  
Author(s):  
Nicolas Kunath ◽  
Anna Maria Bugaj ◽  
Pegah Bigonah ◽  
Marion Silvana Fernandez-Berrocal ◽  
Magnar Bjørås ◽  
...  
Keyword(s):  
Dna Repair ◽  
Hippocampal Neurons ◽  
Spatial Information ◽  
Excision Repair ◽  
Place Cells ◽  
Neural Representation ◽  
Brain Functions ◽  
Dna Base Excision Repair ◽  
Representation Of Space ◽  
Base Excision

ABSTRACTDNA repair enzymes are essential for the maintenance of neuronal genome and thereby proper brain functions. NEIL3 is a member of the NEIL family DNA glycosylases initiating oxidative DNA base excision repair. Recent studies show that NEIL3-deficiency leads to impaired spatial performance in mice, decreased adult neurogenesis and altered synaptic composition in the hippocampus. However, it remains elusive how NEIL3 contributes to spatial information coding in hippocampal neurons. Here, we revealed impaired spatial stability in Neil3−/− CA1 place cells, demonstrating a functional interference of NEIL3 with spatial representations. We identified NEIL3-dependent transcriptional changes in response to spatial exploration and defined its regulatory role specifically for NMDA receptor subunits and immediate early genes. Our work demonstrates a non-canonical role of NEIL3 in modulating the functional plasticity of place cells by shaping the neuronal transcriptome, thus sheds light on the molecular determinants enabling a stable neural representation of space.

scholarly journals Geospatial Open Data Usage and Metadata Quality

2021 ◽  
Vol 10 (1) ◽  
pp. 30
Author(s):  
Alfonso Quarati ◽  
Monica De Martino ◽  
Sergio Rosim
Keyword(s):  
Spatial Information ◽  
Open Data ◽  
Poor Quality ◽  
Data Usage ◽  
Open Government Data ◽  
Metadata Quality ◽  
Geospatial Datasets ◽  
Government Data ◽  
Determining Factor

The Open Government Data portals (OGD), thanks to the presence of thousands of geo-referenced datasets, containing spatial information are of extreme interest for any analysis or process relating to the territory. For this to happen, users must be enabled to access these datasets and reuse them. An element often considered as hindering the full dissemination of OGD data is the quality of their metadata. Starting from an experimental investigation conducted on over 160,000 geospatial datasets belonging to six national and international OGD portals, this work has as its first objective to provide an overview of the usage of these portals measured in terms of datasets views and downloads. Furthermore, to assess the possible influence of the quality of the metadata on the use of geospatial datasets, an assessment of the metadata for each dataset was carried out, and the correlation between these two variables was measured. The results obtained showed a significant underutilization of geospatial datasets and a generally poor quality of their metadata. In addition, a weak correlation was found between the use and quality of the metadata, not such as to assert with certainty that the latter is a determining factor of the former.

Using spatial information for evaluating the quality of prediction maps from hyperspectral images: A geostatistical approach

2019 ◽  
Vol 1077 ◽  
pp. 116-128 ◽  
Author(s):  
Ana Herrero-Langreo ◽  
Nathalie Gorretta ◽  
Bruno Tisseyre ◽  
Aoife Gowen ◽  
Jun-Li Xu ◽  
...  
Keyword(s):  
Spatial Information ◽  
Hyperspectral Images ◽  
Geostatistical Approach
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