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Updated: Apr 3, 2026
Investigating Long-term Synaptic Plasticity in Interlamellar Hippocampus CA1 by Electrophysiological Field Recording
Published on: August 11, 2019
Modulating Hippocampal Plasticity with In Vivo Brain Stimulation
Joyce G Rohan1, Kim A Carhuatanta2, Shawn M McInturf3
1Naval Medical Research Unit Dayton, Environmental Health Effects Directorate and Oak Ridge Institute for Science and Education, Oak Ridge, Tennessee 37831, and Joyce.Rohan.ctr@us.af.mil.
Transcranial direct current stimulation (tDCS) enhances synaptic plasticity in rats, improving long-term potentiation (LTP) and paired-pulse facilitation (PPF). These effects, particularly LTP enhancement, persist for 24 hours, indicating tDCS modifies brain function.
Area of Science:
- Neuroscience
- Neurophysiology
Background:
- Transcranial direct current stimulation (tDCS) shows promise for neurological disorders and cognitive enhancement.
- The precise mechanisms underlying tDCS effects on brain function require further investigation.
Purpose of the Study:
- To investigate the in vivo mechanisms of tDCS effects on hippocampal synaptic plasticity in rats.
- To determine the dose-dependent and time-dependent effects of tDCS on neuronal activity.
Main Methods:
- In vivo tDCS was applied to rats at varying intensities (0.10 mA, 0.25 mA) for 30 minutes.
- Ex vivo hippocampal slices were used to measure long-term potentiation (LTP) and paired-pulse facilitation (PPF) using extracellular recordings.
- The persistence of tDCS effects was assessed 24 hours post-stimulation, with and without NMDA receptor blockade (AP-5).
Main Results:
- tDCS significantly enhanced LTP induction (twofold) and PPF (30%) in hippocampal slices.
- A dose-dependent relationship was observed, with higher intensity (0.25 mA) yielding greater LTP enhancement.
- Enhanced LTP induction persisted for 24 hours post-tDCS, while PPF enhancement did not.
- NMDA receptor blockade abolished LTP but preserved PPF enhancement in stimulated rats.
Conclusions:
- Non-invasive tDCS effectively modifies hippocampal synaptic plasticity in rats.
- These findings provide insights into the molecular mechanisms underlying tDCS-induced cognitive and performance enhancements.
- Understanding these mechanisms can lead to improved therapeutic applications of brain stimulation.
