Although it is well known that high-frequency stimulation (HFS) of the subthalamic nucleus (STN) alleviates the cardinal symptoms of Parkinson's disease, the underlying mechanisms are not fully understood. We investigated the effect of stimulation from low to high frequencies on rat STN neurons in naive and dopamine-depleted slices using whole-cell, current-clamp techniques and on-line artifact suppression. Stimulation at 10 Hz evoked 10 Hz single spikes but did not significantly modify ongoing STN activity. In contrast, at therapeutically relevant frequencies (80-185 Hz), stimulation had a dual effect: it fully suppressed STN spontaneous activity and generated a robust pattern of recurrent bursts of spikes, with each spike being time-locked to a stimulus pulse. Neither the suppression of spontaneous activity nor the generation of spikes was prevented by the antagonists of the metabotropic and ionotropic receptors of glutamate and gamma-aminobutyric acid. Tetrodotoxin, the Na+ channel blocker, suppressed all HFS-evoked spikes, whereas nifedipin, an L-type Ca2+-channel blocker, abolished the membrane oscillations underlying bursts. Therefore, we conclude that HFS drives the STN neuronal activity by directly activating the neuronal membrane. We suggest that this pattern may remove the deleterious activity of the basal ganglia network in the parkinsonian state and drive target neurons to a high-frequency state of activity, dependent on the characteristics of STN efferent synapses and resonant properties of target membranes.
Download full-text PDF |
Source |
---|---|
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6740410 | PMC |
http://dx.doi.org/10.1523/JNEUROSCI.23-25-08743.2003 | DOI Listing |
Front Neural Circuits
January 2025
Department of Neurobiology, Hokkaido University Graduate School of Medicine, Sapporo, Japan.
A strong repetitive stimulus can occasionally enhance axonal excitability, leading to the generation of afterdischarge. This afterdischarge outlasts the stimulus period and originates either from the physiological spike initiation site, typically the axon initial segment, or from ectopic sites for spike generation. One of the possible mechanisms underlying the stimulus-induced ectopic afterdischarge is the local depolarization due to accumulated potassium ions surrounding the axonal membranes of the distal portion.
View Article and Find Full Text PDFFront Neurosci
January 2025
School of Electronic Information and Communications, Huazhong University of Science and Technology, Wuhan City, China.
Introduction: Transcranial magnetic stimulation (TMS) is widely used for the noninvasive activation of neurons in the human brain. It utilizes a pulsed magnetic field to induce electric pulses that act on the central nervous system, altering the membrane potential of nerve cells in the cerebral cortex to treat certain mental diseases. However, the effectiveness of TMS can be compromised by significant heat generation and the clicking noise produced by the pulse in the TMS coil.
View Article and Find Full Text PDFJ Neurosci
January 2025
Department of Biomedical Engineering, Michigan Technological University, 1400 Townsend Dr. Houghton, MI 49931.
Deep brain stimulation (DBS) effectively treats motor symptoms of advanced Parkinson's disease (PD), with the globus pallidus interna (GPi) commonly targeted. However, its therapeutic mechanisms remain unclear. We employed optogenetic stimulation in the entopeduncular nucleus (EP), the rat homologue of GPi, in a unilateral 6-OHDA lesioned female Sprague Dawley rat model of PD.
View Article and Find Full Text PDFPflugers Arch
January 2025
Department of Neuroscience, Graduate School of Biomedical Sciences, Mayo Clinic College of Medicine, Phoenix, AZ, USA.
To examine the effect of DBS of the lateral hypothalamic area (LHA) on age-related memory changes, neuronal firing from CA1, oxidative stress, and the expression of Hsp70, BDNF, and synaptophysin. 72 male rats were randomly allocated into 6 equal groups: a) normal young group (8 W), b) sham young group, c) DBS young group, d) normal old group (24 months), e) sham old group and f) DBS old group. Memory tests (passive avoidance and Y maze), oxidative stress markers (MDA, catalase, and GSH) and expression of Nrf2, HO-1, Hsp70, BDNF, and synaptophysin were measured by the end of the experiment.
View Article and Find Full Text PDFEur J Pain
February 2025
Center for Mathematics, Computation and Cognition, Federal University of ABC, São Bernardo do Campo, SP, Brazil.
Background And Objective: Non-invasive neuromodulation techniques (NIN), such as transcranial Direct Current Stimulation (tDCS) and repetitive Transcranial Magnetic Stimulation (rTMS), have been extensively researched for their potential to alleviate pain by reversing neuroplastic changes associated with neuropathic pain (NP), a prevalent and complex condition. However, treating NP remains challenging due to the numerous variables involved, such as different techniques, dosages and aetiologies. It is necessary to provide insights for clinicians and public healthcare managers to support clinical decision-making.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!