In Vivo Calcium Imaging of Granule Cells in the Dentate Gyrus of Hippocampus in Mice

Shanshan Han; Ning Ding; Ce Li; Peng Yuan

doi:10.3791/66916

In Vivo Calcium Imaging of Granule Cells in the Dentate Gyrus of Hippocampus in Mice

JoVE Journal
Neuroscience

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JoVE Journal Neuroscience

In Vivo Calcium Imaging of Granule Cells in the Dentate Gyrus of Hippocampus in Mice

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07:00 min

August 2, 2024

DOI: 10.3791/66916-v

Shanshan Han¹, Ning Ding¹, Ce Li¹, Peng Yuan¹

¹Department of Rehabilitation Medicine, Huashan Hospital, State Key Laboratory of Medical Neurobiology, Institute for Translational Brain Research, MOE Frontiers Center for Brain Science, MOE Innovative Center for New Drug Development of Immune Inflammatory Diseases,Fudan University

Overview

This study outlines a protocol for in vivo calcium imaging of granule cells in the dentate gyrus of the hippocampus in freely moving mice. Focused on investigating neuroactivities, the protocol combines virus injection and GRIN lens implantation in a single surgical procedure. This novel approach aims to enhance data quality and accuracy in understanding the neural coding and spatial representations in cognitive functions.

Key Study Components

Area of Science

Neuroimaging
Neuroscience
Cognition

Background

The dentate gyrus plays a crucial role in learning and memory.
Calcium imaging is vital for studying neuronal activities in real-time.
Traditional methods separate virus injection and lens implantation, which can lead to inaccuracies.
In vivo imaging allows for the observation of neural dynamics during cognitive tasks.

Purpose of Study

To improve the efficiency and accuracy of in vivo calcium imaging.
To facilitate the study of neuronal activity correlating with cognitive functions.
To understand the mechanisms underlying spatial representations in the dentate gyrus.

Methods Used

In vivo calcium imaging was performed using a miniature microscope.
The biological model included granule cells in the dentate gyrus of freely moving mice.
The protocol integrates virus injection with GRIN lens implantation to streamline the procedure.
Critical steps involve precise surgical techniques to ensure accurate placements.
Data analysis includes motion correction and single-cell signal extraction from imaging data.

Main Results

Successful imaging revealed varying numbers of active cells based on visibility of blood vessels.
Data showed individual cell responses that illuminate the coding properties of the dentate gyrus.
The integration of surgical steps enhances the overall quality of collected data.
Different active cell counts were associated with imaging field quality.

Conclusions

The study demonstrates an effective method for in vivo calcium imaging in freely moving mice.
This approach facilitates improved examination of neuroactivities related to cognitive processing.
Results have implications for understanding cognitive mechanisms and potential neurological disorders.

Frequently Asked Questions

What are the advantages of the combined surgical approach?

Combining virus injection and GRIN lens implantation minimizes wait times and improves accuracy, leading to better imaging quality.

How is the biological model implemented in the study?

The model involves freely moving mice with granule cells in the dentate gyrus being studied for neuroactivities using calcium imaging.

What types of data are obtained from calcium imaging?

The imaging provides insights into the neurodynamic patterns associated with cognition and allows for the identification of active neurons.

How can this method be adapted for other research?

This protocol can be modified for different neuroanatomical regions or species, enhancing its applicability in various neuroscience research contexts.

Are there any limitations to the protocol?

Key considerations include ensuring proper placement of the GRIN lens and maintaining clear visibility during imaging, which may require advanced surgical skills.

What implications do the findings have for understanding brain function?

The study's findings contribute to a deeper understanding of how spatial representations and neural coding underpin cognitive functions in the brain.

The dentate gyrus of the hippocampus carries out essential and distinct functions in learning and memory. This protocol describes a set of robust and efficient procedures for in vivo calcium imaging of granule cells in the dentate gyrus in freely moving mice.

Well, in this protocol, we use a miniature microscope to investigate the neuroactivities in the dentate gyrus of the hippocampus. We aim to investigate neuron coding and spatial representations during the different disease conditions. I believe the key challenge of studying dentate gyrus in vivo involves obtaining high quality calcium imaging data.

Whether the various expression is satisfactory, whether the GRIN lens is implanted at the proper location, and the details like this during the entire surgery are critical importance for the success of the study. In the traditional calcium imaging surgery, the virus injection and the GRIN lens implantation are typically performed as separate operations. In our protocol, we combined these two steps into a single procedure, which not only reduces the waiting time, but also ensures the accurate placement of the GRIN lens.

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