Place cells, neocortex and spatial navigation: a short review

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.

Download Full-text

The Hippocampus

Evolutionary Neuropsychology ◽

10.1093/oso/9780190940942.003.0008 ◽

2020 ◽

pp. 166-179

Author(s):

Frederick L. Coolidge

Keyword(s):

Spatial Navigation ◽

Place Cells ◽

Grid Cells ◽

Stable Maps ◽

Olfactory Bulbs ◽

Additional Stimulation

All mammals have a well-developed hippocampus compared to that of fish, reptiles, and birds, although the latter still have homologous structures. The cells of the hippocampus have differentiated roles: place cells become active and rearrange themselves in new environments, which create new and stable maps of those environments. Grid cells are able to approximate distances, forming an additional neuronal basis for spatial navigation. The hippocampus and olfactory bulbs have intimately related functions. The story of patient H.M. revealed that declarative memories are consolidated by the hippocampus, but procedural memories can be established without hippocampal involvement. Declarative memories remain vulnerable to disruption and forgetting up to about 3 years after memorization. Memories consolidated during sleep are less prone to interference and more stable than memories followed by additional stimulation or learning.

Download Full-text

Recurrent network model for learning goal-directed sequences through reverse replay

eLife ◽

10.7554/elife.34171 ◽

2018 ◽

Vol 7 ◽

Cited By ~ 16

Author(s):

Tatsuya Haga ◽

Tomoki Fukai

Keyword(s):

Sequence Learning ◽

Spatial Navigation ◽

Recurrent Network ◽

Place Cells ◽

Spike Timing ◽

Directed Path ◽

Short Term ◽

Reward Seeking ◽

Sequential Activation ◽

First Time

Reverse replay of hippocampal place cells occurs frequently at rewarded locations, suggesting its contribution to goal-directed path learning. Symmetric spike-timing dependent plasticity (STDP) in CA3 likely potentiates recurrent synapses for both forward (start to goal) and reverse (goal to start) replays during sequential activation of place cells. However, how reverse replay selectively strengthens forward synaptic pathway is unclear. Here, we show computationally that firing sequences bias synaptic transmissions to the opposite direction of propagation under symmetric STDP in the co-presence of short-term synaptic depression or afterdepolarization. We demonstrate that significant biases are created in biologically realistic simulation settings, and this bias enables reverse replay to enhance goal-directed spatial memory on a W-maze. Further, we show that essentially the same mechanism works in a two-dimensional open field. Our model for the first time provides the mechanistic account for the way reverse replay contributes to hippocampal sequence learning for reward-seeking spatial navigation.

Download Full-text

Recurrent network model for learning goal-directed sequences through reverse replay

10.1101/217422 ◽

2017 ◽

Author(s):

Tatsuya Haga ◽

Tomoki Fukai

Keyword(s):

Sequence Learning ◽

Spatial Navigation ◽

Recurrent Network ◽

Place Cells ◽

Spike Timing ◽

Short Term ◽

Reward Seeking ◽

Significant Bias ◽

Sequential Activation ◽

First Time

ABSTRACTReverse replay of hippocampal place cells occurs frequently at rewarded locations, suggesting its contribution to goal-directed pathway learning. Symmetric spike-timing dependent plasticity (STDP) in CA3 likely potentiates recurrent synapses for both forward (start to goal) and reverse (goal to start) replays during sequential activation of place cells. However, how reverse replay selectively strengthens forward pathway is unclear. Here, we show computationally that firing sequences bias synaptic transmissions to the opposite direction of propagation under symmetric, but not asymmetric, STDP in the co-presence of short-term synaptic plasticity. We demonstrate that a significant bias can be created in biologically realistic simulation settings, and that this bias enables reverse replay to enhance goal-directed spatial memory on a T-maze. Our model for the first time provides the mechanistic account for the way reverse replay contributes to hippocampal sequence learning for reward-seeking spatial navigation.

Download Full-text

Distinct hippocampal-cortical memory representations for experiences associated with movement versus immobility

eLife ◽

10.7554/elife.27621 ◽

2017 ◽

Vol 6 ◽

Cited By ~ 15

Author(s):

Jai Y Yu ◽

Kenneth Kay ◽

Daniel F Liu ◽

Irene Grossrubatscher ◽

Adrianna Loback ◽

...

Keyword(s):

Prefrontal Cortex ◽

Neural Activity ◽

Spatial Representation ◽

Spatial Navigation ◽

Activity Patterns ◽

Place Cells ◽

Neural Mechanisms ◽

Continuous Representation ◽

Hippocampal Ca1 ◽

Memory Representations

While ongoing experience proceeds continuously, memories of past experience are often recalled as episodes with defined beginnings and ends. The neural mechanisms that lead to the formation of discrete episodes from the stream of neural activity patterns representing ongoing experience are unknown. To investigate these mechanisms, we recorded neural activity in the rat hippocampus and prefrontal cortex, structures critical for memory processes. We show that during spatial navigation, hippocampal CA1 place cells maintain a continuous spatial representation across different states of motion (movement and immobility). In contrast, during sharp-wave ripples (SWRs), when representations of experience are transiently reactivated from memory, movement- and immobility-associated activity patterns are most often reactivated separately. Concurrently, distinct hippocampal reactivations of movement- or immobility-associated representations are accompanied by distinct modulation patterns in prefrontal cortex. These findings demonstrate a continuous representation of ongoing experience can be separated into independently reactivated memory representations.

Download Full-text

A novel somatosensory spatial navigation system outside the hippocampal formation

Cell Research ◽

10.1038/s41422-020-00448-8 ◽

2021 ◽

Cited By ~ 3

Author(s):

Xiaoyang Long ◽

Sheng-Jia Zhang

Keyword(s):

Somatosensory Cortex ◽

Spatial Representation ◽

Hippocampal Formation ◽

Spatial Navigation ◽

Place Cells ◽

Head Direction ◽

Head Direction Cells ◽

Sensory Inputs ◽

Boundary Vector ◽

The Brain

AbstractSpatially selective firing of place cells, grid cells, boundary vector/border cells and head direction cells constitutes the basic building blocks of a canonical spatial navigation system centered on the hippocampal-entorhinal complex. While head direction cells can be found throughout the brain, spatial tuning outside the hippocampal formation is often non-specific or conjunctive to other representations such as a reward. Although the precise mechanism of spatially selective firing activity is not understood, various studies show sensory inputs, particularly vision, heavily modulate spatial representation in the hippocampal-entorhinal circuit. To better understand the contribution of other sensory inputs in shaping spatial representation in the brain, we performed recording from the primary somatosensory cortex in foraging rats. To our surprise, we were able to detect the full complement of spatially selective firing patterns similar to that reported in the hippocampal-entorhinal network, namely, place cells, head direction cells, boundary vector/border cells, grid cells and conjunctive cells, in the somatosensory cortex. These newly identified somatosensory spatial cells form a spatial map outside the hippocampal formation and support the hypothesis that location information modulates body representation in the somatosensory cortex. Our findings provide transformative insights into our understanding of how spatial information is processed and integrated in the brain, as well as functional operations of the somatosensory cortex in the context of rehabilitation with brain-machine interfaces.

Download Full-text

Spatial navigation and multiscale representation by hippocampal place cells

Nature Precedings ◽

10.1038/npre.2011.6379.1 ◽

2011 ◽

Author(s):

Jason Prentice ◽

Josh Merel ◽

Vijay Balasubramanian

Keyword(s):

Spatial Navigation ◽

Place Cells ◽

Multiscale Representation

Download Full-text

Biomimetic FPGA-based spatial navigation model with grid cells and place cells

Neural Networks ◽

10.1016/j.neunet.2021.01.028 ◽

2021 ◽

Author(s):

Adithya Krishna ◽

Divyansh Mittal ◽

Siri Garudanagiri Virupaksha ◽

Abhishek Ramdas Nair ◽

Rishikesh Narayanan ◽

...

Keyword(s):

Spatial Navigation ◽

Place Cells ◽

Grid Cells

Download Full-text

Pollutant Identification by Selected Area Electron Diffraction

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100052675 ◽

1974 ◽

Vol 32 ◽

pp. 532-533

Author(s):

R. E. Ferrell ◽

G. G. Paulson ◽

C. W. Walker

Keyword(s):

Thermal Treatment ◽

Electron Diffraction ◽

Sample Preparation ◽

Crystal Structures ◽

Water Samples ◽

Environmental Samples ◽

Short Review ◽

Selected Area Electron Diffraction ◽

Multiple Component

Selected area electron diffraction (SAD) has been used successfully to determine crystal structures, identify traces of minerals in rocks, and characterize the phases formed during thermal treatment of micron-sized particles. There is an increased interest in the method because it has the potential capability of identifying micron-sized pollutants in air and water samples. This paper is a short review of the theory behind SAD and a discussion of the sample preparation employed for the analysis of multiple component environmental samples.

Download Full-text