Lattice Cells (Grid Cells)
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<th class="infobox-header" colspan="2">Lattice Cells</th>
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<td class="label">Name</td>
<td><strong>Lattice Cells</strong></td>
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<td class="label">Type</td>
<td>Cell Type</td>
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Introduction
Lattice Cells is an important cell type in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.
Overview
Lattice cells, more commonly known as grid cells, are a fundamental class of spatial navigation neurons in the medial entorhinal cortex (MEC) that generate a periodic hexagonal grid pattern of firing fields across the environment.[@fyhn2004][@hafting2005] Discovered by Moser, Moser, and colleagues in 2005, grid cells revolutionized our understanding of how the brain represents space and are considered one of the most important neural coding discoveries in recent decades.[@moser2014]
These neurons fire when an animal moves through multiple discrete locations arranged in a hexagonal lattice pattern. The spacing between firing fields is remarkably consistent within an individual grid cell but varies across different cells (typically 20-50 cm in rats, 2-5 meters in humans). This hexagonal grid provides the neural substrate for path integration—the process by which animals calculate their position based on self-motion cues.[@fyhn2004][@moser2015]
Discovery and Historical Context
...Lattice Cells (Grid Cells)
<table class="infobox infobox-cell">
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<th class="infobox-header" colspan="2">Lattice Cells</th>
</tr>
<tr>
<td class="label">Name</td>
<td><strong>Lattice Cells</strong></td>
</tr>
<tr>
<td class="label">Type</td>
<td>Cell Type</td>
</tr>
</table>
Introduction
Lattice Cells is an important cell type in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.
Overview
Lattice cells, more commonly known as grid cells, are a fundamental class of spatial navigation neurons in the medial entorhinal cortex (MEC) that generate a periodic hexagonal grid pattern of firing fields across the environment.[@fyhn2004][@hafting2005] Discovered by Moser, Moser, and colleagues in 2005, grid cells revolutionized our understanding of how the brain represents space and are considered one of the most important neural coding discoveries in recent decades.[@moser2014]
These neurons fire when an animal moves through multiple discrete locations arranged in a hexagonal lattice pattern. The spacing between firing fields is remarkably consistent within an individual grid cell but varies across different cells (typically 20-50 cm in rats, 2-5 meters in humans). This hexagonal grid provides the neural substrate for path integration—the process by which animals calculate their position based on self-motion cues.[@fyhn2004][@moser2015]
Discovery and Historical Context
The discovery of grid cells emerged from research on spatial cognition and memory. In 2005,Fyhn and colleagues published the landmark paper describing grid cells in the medial entorhinal cortex of freely moving rats.[@fyhn2004] This discovery built upon earlier work on place cells in the hippocampus (discovered by O'Keefe and Dostrovsky in 1971) and head direction cells (discovered by Taube et al. in 1985).[@okeefe1971]
The significance of this discovery was recognized with the 2014 Nobel Prize in Physiology or Medicine, awarded to John O'Keefe, May-Britt Moser, and Edvard I. Moser for their discoveries of cells that constitute a positioning system in the brain.[@the2014]
Cellular Properties
Morphology and Distribution
Grid cells are primarily located in the medial entorhinal cortex (MEC), particularly in layers II and III. They exhibit characteristic morphological features:
- Soma location: Layer II/III of MEC (dorsal-to-ventral gradient)
- Dendritic morphology: Stellate or pyramidal-like cells
- Axonal projections: Dense projections to the hippocampal formation
- Grid scale: Increases from dorsal to ventral MEC[@sargolini2006][@boccara2010]
The dorsal-most grid cells (closest to the postrhinal border) have the smallest grid spacing (~20-30 cm), while ventral grid cells have progressively larger spacing (>50 cm). This gradient correlates with the functional organization of the MEC.[@brun2008]
Molecular Markers
Grid cells express specific molecular markers:
- HCN1: Hyperpolarization-activated cyclic nucleotide-gated channel 1
- Reelin: Extracellular matrix glycoprotein
- Calbindin: Calcium-binding protein (layer II)
- Wnt2: Wingless-type MMTV integration site family member 2
- Cux2: Cut-like homeobox 2 (layer II markers)[@ray2014][@bonnevie2013]
Electrophysiology
Grid cells exhibit unique electrophysiological properties:
- Firing pattern: Spatially periodic action potential bursts
- Theta oscillation: Phase precession within theta cycles (5-12 Hz)
- Grid fields: 5-10 firing fields per environment
- Field spacing: Characteristic hexagonal arrangement
- Phase locking: Temporal relationship to theta oscillations[@fyhn2004][@skaggs1996]
Grid Pattern Generation
Theoretical Models
The mechanisms underlying grid pattern generation have been subject to intense investigation:
Continuous attractor network model: Suggests that grid patterns emerge from recurrent connections between grid cells that form a continuous attractor network. This model proposes that:
- Grid cells form excitatory networks with their neighbors
- Network activity stabilizes at grid patterns
- Movement signals shift the activity bump[@fuhs2006]
Oscillatory interference model: Proposes that grid patterns arise from interference between:
- Theta oscillations (5-12 Hz)
- Velocity-controlled oscillators
- Dendritic theta inputs[@burgess2007]
Single-cell model: Suggests that grid properties can emerge from:
- Intrinsic neuronal properties
- Dendritic computation
- Synaptic integration dynamics[@navratilova2010]
Circuit Integration
Grid cells integrate information from multiple sources:
- Head direction cells: Directional information
- Speed cells: Running speed signals
- Border cells: Environmental boundaries
- Self-motion signals: Vestibular and proprioceptive cues[@kropff2015][@solstad2008]
Functional Roles
Spatial Navigation
Grid cells provide a metric for space:
Path integration: Calculate position from movement history
Spatial memory: Form cognitive maps with hippocampus
Goal-directed navigation: Support route planning
Vector navigation: Calculate direct paths to goals[@mcnaughton2006][@bush2014]Episodic Memory
The grid cell-hippocampal circuit supports episodic memory:
- Contextual representation: Spatial framework for memories
- Memory consolidation: Hippocampal-cortical dialogue
- Imagination: Mental navigation of remembered environments
- Prospection: Planning future routes[@buzsaki2013][@moser2011]
Temporal Coding
Grid cells contribute to temporal coding:
- Theta phase precession: Firing phases shift as animals traverse fields
- Temporal sequences: Grid cells encode temporal relationships
- Memory traces: Support episodic memory formation[@dragoi2006]
Role in Neurodegenerative Diseases
Alzheimer's Disease
Grid cells are particularly vulnerable in Alzheimer's disease:
Early pathology: The entorhinal cortex is one of the first brain regions to show tau pathology in AD, directly affecting grid cells before other cortical areas.[@braak1991]
Grid disruption:
- Reduced grid field precision
- Impaired phase precession
- Altered theta oscillations
- Grid scale abnormalities[@marks2019][@palop2016]
Clinical correlates:
- Spatial disorientation (early symptom)
- Navigation deficits
- Topographical memory impairment
- Wandering behavior[@hort2007]
Neuroimaging findings:
- Reduced MEC volume on MRI
- Hypometabolism on FDG-PET
- Tau accumulation in MEC (PET)[@khan2014]
Parkinson's Disease
Grid cell dysfunction contributes to:
- Navigation impairment: Difficulty with route learning
- Spatial memory deficits: Problems with spatial recall
- Freezing of gait: Relationship to spatial processing
- REM behavior disorder: Entorhinal involvement[@verbaan2007]
Therapeutic Implications
Understanding grid cell pathology provides therapeutic opportunities:
- Early biomarkers: MEC functional imaging
- Navigation training: Spatial rehabilitation
- Deep brain stimulation: Modulating grid cell networks
- Transcranial stimulation: Targeting entorhinal circuits[@fellous2019]
Research Methods
Electrophiology
- In vivo recordings: Extracellular single-unit recording
- Tetrodes: Multi-unit recording arrays
- Silicon probes: High-density recording
- Optogenetics: Cell-type specific manipulation[@zugaro2018]
Imaging
- Two-photon calcium imaging: Cellular activity
- fMRI: Population-level activation
- PET: Tau and amyloid imaging
- Diffusion MRI: Structural connectivity[@strange2014]
Behavioral Tasks
- Open field foraging: Spatial navigation
- Morris water maze: Spatial memory
- Virtual reality: Human navigation
- VR tasks: Grid cell correlates[@doeller2010]
See Also
- [Entorhinal Cortex Neurons
- Medial Entorhinal Cortex GABAergic Neurons
- [Place Cells](/cell-types/place-cells)
- [Head Direction Cells](/cell-types/head-direction-cells)
- [Speed Cells](/cell-types/speed-cells)
- Border Cells](/cell-types/entorhinal-cortex-neurons
--medial-entorhinal-cortex-gabaergic-neurons
--place-cells
--head-direction-cells
--speed-cells
--border-cells)
- [Alzheimer's Disease](/diseases/alzheimers-disease)
- [Medial Septal Nucleus Cholinergic Neurons
](/cell-types/medial-septal-nucleus-cholinergic-neurons)## Background
The study of Lattice Cells has evolved significantly over the past decades. Research in this area has revealed important insights into the underlying mechanisms of neurodegeneration and continues to drive therapeutic development.
Historical context and key discoveries in this field have shaped our current understanding and will continue to guide future research directions.
External Links
- [PubMed](https://pubmed.ncbi.nlm.nih.gov/) - Biomedical literature
- [Alzheimer's Disease Neuroimaging Initiative](https://adni.loni.usc.edu/) - Research data
- [Allen Brain Atlas](https://brain-map.org/) - Brain gene expression data