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Linking cellular mechanisms to behavior: entorhinal persistent spiking and membrane potential oscillations may underlie path integration, grid cell firing, and episodic memory.

Hasselmo ME, Brandon MP - Neural Plast. (2008)

Bottom Line: The entorhinal cortex plays an important role in spatial memory and episodic memory functions.This article reviews physiological data on persistent spiking and membrane potential oscillations in entorhinal cortex then presents models showing how both these cellular mechanisms could contribute to properties observed during unit recording, including grid cell firing, and how they could underlie behavioural functions including path integration.The interaction of oscillations and persistent firing could contribute to encoding and retrieval of trajectories through space and time as a mechanism relevant to episodic memory.

View Article: PubMed Central - PubMed

Affiliation: Center for Memory and Brain, Department of Psychology and Program in Neuroscience, Boston University, 2 Cummington Sreet, Boston, MA 02215, USA. hasselmo@bu.edu

ABSTRACT
The entorhinal cortex plays an important role in spatial memory and episodic memory functions. These functions may result from cellular mechanisms for integration of the afferent input to entorhinal cortex. This article reviews physiological data on persistent spiking and membrane potential oscillations in entorhinal cortex then presents models showing how both these cellular mechanisms could contribute to properties observed during unit recording, including grid cell firing, and how they could underlie behavioural functions including path integration. The interaction of oscillations and persistent firing could contribute to encoding and retrieval of trajectories through space and time as a mechanism relevant to episodic memory.

Show MeSH
Phase relative to location in theenvironment.  (a) Spiking phase due toprecession (with refractory period). Note that phase depends upon location, but is circularly symmetric.  (b) Dendritic phase of oscillations containsmore complete continuous representation of location.  (c) Plot of the angle of a single distalvisual stimulus as a rat moves around in an environment, indicating similarityof allocentric stimulus angle to integrated dendritic phase in a grid cell.
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fig5: Phase relative to location in theenvironment. (a) Spiking phase due toprecession (with refractory period). Note that phase depends upon location, but is circularly symmetric. (b) Dendritic phase of oscillations containsmore complete continuous representation of location. (c) Plot of the angle of a single distalvisual stimulus as a rat moves around in an environment, indicating similarityof allocentric stimulus angle to integrated dendritic phase in a grid cell.

Mentions: Note that the phase precession for a singledirection gives a partial readout of the phase code of location, but whenconsidering the phase in two-dimensional space, it confounds the phase of the two or moredendrites, so it is radially symmetric and dependent upon the direction oftrajectory through the field (see Figure 5(a)). Thus, the phaseprecession code is less accurate for use in path integration, in contrast tothe overall mean firing rate that would be observed in a grid cell due topersistent firing with a very large firing field, which could code location fordistances smaller than one half the spacing between two grid fields (e.g., for 80 cm spacing,distances less than 40 cm could be coded).


Linking cellular mechanisms to behavior: entorhinal persistent spiking and membrane potential oscillations may underlie path integration, grid cell firing, and episodic memory.

Hasselmo ME, Brandon MP - Neural Plast. (2008)

Phase relative to location in theenvironment.  (a) Spiking phase due toprecession (with refractory period). Note that phase depends upon location, but is circularly symmetric.  (b) Dendritic phase of oscillations containsmore complete continuous representation of location.  (c) Plot of the angle of a single distalvisual stimulus as a rat moves around in an environment, indicating similarityof allocentric stimulus angle to integrated dendritic phase in a grid cell.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2480478&req=5

fig5: Phase relative to location in theenvironment. (a) Spiking phase due toprecession (with refractory period). Note that phase depends upon location, but is circularly symmetric. (b) Dendritic phase of oscillations containsmore complete continuous representation of location. (c) Plot of the angle of a single distalvisual stimulus as a rat moves around in an environment, indicating similarityof allocentric stimulus angle to integrated dendritic phase in a grid cell.
Mentions: Note that the phase precession for a singledirection gives a partial readout of the phase code of location, but whenconsidering the phase in two-dimensional space, it confounds the phase of the two or moredendrites, so it is radially symmetric and dependent upon the direction oftrajectory through the field (see Figure 5(a)). Thus, the phaseprecession code is less accurate for use in path integration, in contrast tothe overall mean firing rate that would be observed in a grid cell due topersistent firing with a very large firing field, which could code location fordistances smaller than one half the spacing between two grid fields (e.g., for 80 cm spacing,distances less than 40 cm could be coded).

Bottom Line: The entorhinal cortex plays an important role in spatial memory and episodic memory functions.This article reviews physiological data on persistent spiking and membrane potential oscillations in entorhinal cortex then presents models showing how both these cellular mechanisms could contribute to properties observed during unit recording, including grid cell firing, and how they could underlie behavioural functions including path integration.The interaction of oscillations and persistent firing could contribute to encoding and retrieval of trajectories through space and time as a mechanism relevant to episodic memory.

View Article: PubMed Central - PubMed

Affiliation: Center for Memory and Brain, Department of Psychology and Program in Neuroscience, Boston University, 2 Cummington Sreet, Boston, MA 02215, USA. hasselmo@bu.edu

ABSTRACT
The entorhinal cortex plays an important role in spatial memory and episodic memory functions. These functions may result from cellular mechanisms for integration of the afferent input to entorhinal cortex. This article reviews physiological data on persistent spiking and membrane potential oscillations in entorhinal cortex then presents models showing how both these cellular mechanisms could contribute to properties observed during unit recording, including grid cell firing, and how they could underlie behavioural functions including path integration. The interaction of oscillations and persistent firing could contribute to encoding and retrieval of trajectories through space and time as a mechanism relevant to episodic memory.

Show MeSH