scholarly journals Refinement and reactivation of a taste-responsive hippocampal network

2019 ◽  
Author(s):  
Linnea E. Herzog ◽  
Donald B. Katz ◽  
Shantanu P. Jadhav
Keyword(s):  
Place Cells ◽  
Food Sources ◽  
Ca1 Region ◽  
Co Activation ◽  
Place Fields ◽  
Mental Map ◽  
Hippocampal Network ◽  
Taste Exposure ◽  
Toxic Food ◽  
Taste Experience

SummaryAnimals need to remember the locations of nourishing and toxic food sources for survival, a fact that necessitates a mechanism for associating taste experiences with particular places. We have previously identified such responses within hippocampal place cells [1], the activity of which is thought to aid memory-guided behavior by forming a mental map of an animal’s environment that can be reshaped through experience [2–7]. It remains unknown, however, whether taste-responsiveness is intrinsic to a subset of place cells, or emerges as a result of experience that reorganizes spatial maps. Here, we recorded from neurons in the dorsal CA1 region of rats running for palatable tastes delivered via intra-oral cannulae at specific locations on a linear track. We identified a subset of taste-responsive cells that, even prior to taste exposure, had larger place fields than non-taste-responsive cells overlapping with stimulus delivery zones. Taste-responsive cells’ place fields then contracted, as a result of taste experience, leading to a stronger representation of stimulus delivery zones on the track. Taste-responsive units exhibited increased sharp-wave ripple co-activation during the taste delivery session and subsequent rest periods, which correlated with the degree of place field contraction. Our results reveal that novel taste experience evokes responses within a preconfigured network of taste-responsive hippocampal place cells with large fields, whose spatial representations are refined by sensory experience to signal areas of behavioral salience. This represents a possible mechanism by which animals identify and remember locations where ecologically relevant stimuli are found within their environment.

scholarly journals Disrupted Co-activation of Interneurons and Hippocampal Network after Focal Kainate Lesion

2017 ◽  
Vol 11 ◽  
Author(s):  
Lim-Anna Sieu ◽  
Emmanuel Eugène ◽  
Agnès Bonnot ◽  
Ivan Cohen
Keyword(s):  
Co Activation ◽  
Hippocampal Network

Hippocampal Place-Cell Firing During Movement in Three-Dimensional Space

2001 ◽  
Vol 85 (1) ◽  
pp. 105-116 ◽  
Author(s):  
James J. Knierim ◽  
Bruce L. McNaughton
Keyword(s):  
Hippocampal Neurons ◽  
Horizontal Plane ◽  
Three Dimensional ◽  
Place Cell ◽  
Place Cells ◽  
Limbic Cortex ◽  
Head Direction ◽  
Head Direction Cells ◽  
Recording Apparatus ◽  
Place Fields

“Place” cells of the rat hippocampus are coupled to “head direction” cells of the thalamus and limbic cortex. Head direction cells are sensitive to head direction in the horizontal plane only, which leads to the question of whether place cells similarly encode locations in the horizontal plane only, ignoring the z axis, or whether they encode locations in three dimensions. This question was addressed by recording from ensembles of CA1 pyramidal cells while rats traversed a rectangular track that could be tilted and rotated to different three-dimensional orientations. Cells were analyzed to determine whether their firing was bound to the external, three-dimensional cues of the environment, to the two-dimensional rectangular surface, or to some combination of these cues. Tilting the track 45° generally provoked a partial remapping of the rectangular surface in that some cells maintained their place fields, whereas other cells either gained new place fields, lost existing fields, or changed their firing locations arbitrarily. When the tilted track was rotated relative to the distal landmarks, most place fields remapped, but a number of cells maintained the same place field relative to the x-y coordinate frame of the laboratory, ignoring the z axis. No more cells were bound to the local reference frame of the recording apparatus than would be predicted by chance. The partial remapping demonstrated that the place cell system was sensitive to the three-dimensional manipulations of the recording apparatus. Nonetheless the results were not consistent with an explicit three-dimensional tuning of individual hippocampal neurons nor were they consistent with a model in which different sets of cells are tightly coupled to different sets of environmental cues. The results are most consistent with the statement that hippocampal neurons can change their “tuning functions” in arbitrary ways when features of the sensory input or behavioral context are altered. Understanding the rules that govern the remapping phenomenon holds promise for deciphering the neural circuitry underlying hippocampal function.

scholarly journals Unmasking the CA1 Ensemble Place Code by Exposures to Small and Large Environments: More Place Cells and Multiple, Irregularly Arranged, and Expanded Place Fields in the Larger Space

2008 ◽  
Vol 28 (44) ◽  
pp. 11250-11262 ◽  
Author(s):  
A. A. Fenton ◽  
H.-Y. Kao ◽  
S. A. Neymotin ◽  
A. Olypher ◽  
Y. Vayntrub ◽  
...  
Keyword(s):  
Place Cells ◽  
Place Fields

scholarly journals Mice Expressing Activated CaMKII Lack Low Frequency LTP and Do Not Form Stable Place Cells in the CA1 Region of the Hippocampus

Cell ◽  
1996 ◽  
Vol 87 (7) ◽  
pp. 1351-1361 ◽  
Author(s):  
Alexander Rotenberg ◽  
Mark Mayford ◽  
Robert D Hawkins ◽  
Eric R Kandel ◽  
Robert U Muller
Keyword(s):  
Low Frequency ◽  
Place Cells ◽  
Ca1 Region

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 Preexisting hippocampal network dynamics constrain optogenetically induced place fields

2019 ◽  
Author(s):  
Sam McKenzie ◽  
Roman Huszár ◽  
Daniel F. English ◽  
Kanghwan Kim ◽  
Euisik Yoon ◽  
...  
Keyword(s):  
Hippocampal Neurons ◽  
Inhibitory Interneuron ◽  
Neuronal Circuits ◽  
Place Field ◽  
Large Reservoir ◽  
New Information ◽  
Place Fields ◽  
Hippocampal Network ◽  
Fundamental Tension ◽  
Existing Structure

SummaryNeuronal circuits face a fundamental tension between maintaining existing structure and changing to accommodate new information. Memory models often emphasize the need to encode novel patterns of neural activity imposed by “bottom-up” sensory drive. In such models, learning is achieved through synaptic alterations, a process which potentially interferes with previously stored knowledge 1-3. Alternatively, neuronal circuits generate and maintain a preconfigured stable dynamic, sometimes referred to as an attractor, manifold, or schema 4-7, with a large reservoir of patterns available for matching with novel experiences 8-13. Here, we show that incorporation of arbitrary signals is constrained by pre-existing circuit dynamics. We optogenetically stimulated small groups of hippocampal neurons as mice traversed a chosen segment of a linear track, mimicking the emergence of place fields 1,14,15, while simultaneously recording the activity of stimulated and non-stimulated neighboring cells. Stimulation of principal neurons in CA1, but less so CA3 or the dentate gyrus, induced persistent place field remapping. Novel place fields emerged in both stimulated and non-stimulated neurons, which could be predicted from sporadic firing in the new place field location and the temporal relationship to peer neurons prior to the optogenetic perturbation. Circuit modification was reflected by altered spike transmission between connected pyramidal cell – inhibitory interneuron pairs, which persisted during post-experience sleep. We hypothesize that optogenetic perturbation unmasked sub-threshold, pre-existing place fields16,17. Plasticity in recurrent/lateral inhibition may drive learning through rapid exploration of existing states.

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 Maintaining Consistency of Spatial Information in the Hippocampal Network: A Combinatorial Geometry Model

2016 ◽  
Vol 28 (6) ◽  
pp. 1051-1071 ◽  
Author(s):  
Y. Dabaghian
Keyword(s):  
Spatial Information ◽  
Synaptic Connection ◽  
Cell Activity ◽  
Internal Representation ◽  
Combinatorial Geometry ◽  
Place Cells ◽  
Geometry Model ◽  
Electrophysiological Recordings ◽  
Hippocampal Network ◽  
Proprioceptive Inputs

Place cells in the rat hippocampus play a key role in creating the animal’s internal representation of the world. During active navigation, these cells spike only in discrete locations, together encoding a map of the environment. Electrophysiological recordings have shown that the animal can revisit this map mentally during both sleep and awake states, reactivating the place cells that fired during its exploration in the same sequence in which they were originally activated. Although consistency of place cell activity during active navigation is arguably enforced by sensory and proprioceptive inputs, it remains unclear how a consistent representation of space can be maintained during spontaneous replay. We propose a model that can account for this phenomenon and suggest that a spatially consistent replay requires a number of constraints on the hippocampal network that affect its synaptic architecture and the statistics of synaptic connection strengths.

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