scholarly journals Different Effects of Monophasic Pulses and Biphasic Pulses Applied by a Bipolar Stimulation Electrode in the Rat Hippocampal CA1 Region

2020 ◽  
Author(s):  
Yue Yuan ◽  
Lvpiao Zheng ◽  
Zhouyan Feng ◽  
Gangsheng Yang
Keyword(s):  
Animal Experiments ◽  
Neuronal Firing ◽  
Brain Diseases ◽  
Neuron Activity ◽  
Neuronal Responses ◽  
Population Spikes ◽  
Ca1 Region ◽  
Hippocampal Ca1 Region ◽  
Hippocampal Ca1

Abstract Background: Deep brain stimulation (DBS) has been successfully used for treating certain brain diseases such as movement disorders. High-frequency stimulations (HFS) of charge-balanced biphasic pulses have been used in clinic DBS to minimize the risk of tissue damages caused by the electrical stimulations, while HFS sequences of monophasic pulses have been used in animal experiments to investigate DBS therapy. However, it is not clear whether HFS sequences of monophasic pulses could induce abnormal neuronal responses different from biphasic pulses. Thus, the present study investigates the differences of neuronal responses to HFS of monophasic pulses and biphasic pulses.Methods: Orthodromic-HFS (O-HFS) and antidromic-HFS (A-HFS) of the two types of pulses (with a 1-min duration) were delivered by bipolar electrodes to the Schaffer collaterals (i.e., afferent fibers) and the alveus fibers (i.e., efferent fibers) of the rat hippocampal CA1 region in-vivo, respectively. Responses of CA1 pyramidal neurons to the stimulations were recorded in the CA1 region. Single pulses of antidromic- and orthodromic-test stimuli were applied before and after HFS to evoke population spikes for evaluating the baseline and the recovery of neuronal activity. Results: Spreading depression (SD) appeared during sequences of 200 Hz monophasic O-HFS with a high incidence (4/5), but did not appear during corresponding 200 Hz biphasic O-HFS (0/6). The potential waveform of SD was accompanied by a preceding burst of population spikes, propagated slowly, silenced neuronal firing temporarily and resulted in a non-recovery of orthodromically-evoked population spikes (OPS) after the O-HFS. No SD events appeared during the O-HFS with a lower frequency of 100 Hz of monophasic and biphasic pulses (0/5 and 0/6, respectively) nor during the A-HFS of 200 Hz pulses (0/9). However, the antidromically-evoked population spikes (APS) only recovered partially after the 200 Hz A-HFS of monophasic pulses.Conclusions: The O-HFS with a high enough frequency of monophasic pulses may induce the abnormal neuron activity of SD instantaneously, which may be used as a biomarker to warn the damages caused by improper stimulations in brain tissues.

scholarly journals Different effects of monophasic pulses and biphasic pulses applied by a bipolar stimulation electrode in the rat hippocampal CA1 region

2021 ◽  
Author(s):  
Yue Yuan ◽  
Lvpiao Zheng ◽  
Zhouyan Feng ◽  
Gangsheng Yang
Keyword(s):  
Animal Experiments ◽  
Neuronal Firing ◽  
Neuron Activity ◽  
Partial Recovery ◽  
Neuronal Responses ◽  
Population Spikes ◽  
Ca1 Region ◽  
Hippocampal Ca1 Region ◽  
Hippocampal Ca1

Abstract Background: Electrical pulse stimulations have been applied in brain for treating certain diseases such as movement disorders. High-frequency stimulations (HFS) of biphasic pulses have been used in clinic stimulations, such as deep brain stimulation (DBS), to minimize the risk of tissue damages caused by the electrical stimulations. However, HFS sequences of monophasic pulses have often been used in animal experiments for studying neuronal responses to the stimulations. It is not clear yet what the differences of the neuronal responses to the HFS of monophasic pulses from the HFS of biphasic pulses are. Methods: To investigate the neuronal responses to the two types of pulses, orthodromic-HFS (O-HFS) and antidromic-HFS (A-HFS) of biphasic and monophasic pulses (1-min) were delivered by bipolar electrodes respectively to the Schaffer collaterals (i.e., afferent fibers) and the alveus fibers (i.e., efferent fibers) of the rat hippocampal CA1 region in-vivo. Evoked population spikes of CA1 pyramidal neurons to the HFSs were recorded in the CA1 region. In addition, single pulses of antidromic- and orthodromic-test stimuli were applied before and after HFSs to evaluate the baseline and the recovery of neuronal activity, respectively. Results: Spreading depression (SD) appeared during sequences of 200 Hz monophasic O-HFS with a high incidence (4/5), but did not appear during corresponding 200 Hz biphasic O-HFS (0/6). A preceding burst of population spikes appeared before the SD waveforms. Then, the SD propagated slowly, silenced neuronal firing temporarily and resulted in partial recovery of orthodromically-evoked population spikes (OPS) after the end of O-HFS. No SD events appeared during the O-HFS with a lower frequency of 100 Hz of monophasic or biphasic pulses (0/5 and 0/6, respectively), neither during the A-HFS of 200 Hz pulses (0/9). The antidromically-evoked population spikes (APS) after 200 Hz biphasic A-HFS recovered to baseline level within ~2 min. However, the APS only recovered partially after the 200 Hz A-HFS of monophasic pulses.Conclusions: The O-HFS with a higher frequency of monophasic pulses can induce the abnormal neuron activity of SD and the A-HFS of monophasic pulses can cause a persisting attenuation of neuronal excitability, indicating neuronal damages caused by monophasic stimulations in brain tissues. The results provide guidance for proper stimulation protocols in clinic and animal experiments.

scholarly journals Different effects of monophasic pulses and biphasic pulses applied by a bipolar stimulation electrode in the rat hippocampal CA1 region

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Yue Yuan ◽  
Lvpiao Zheng ◽  
Zhouyan Feng ◽  
Gangsheng Yang
Keyword(s):  
Animal Experiments ◽  
Neuronal Firing ◽  
Neuron Activity ◽  
Partial Recovery ◽  
Neuronal Responses ◽  
Population Spikes ◽  
Ca1 Region ◽  
Hippocampal Ca1 Region ◽  
Hippocampal Ca1

Abstract Background Electrical pulse stimulations have been applied in brain for treating certain diseases such as movement disorders. High-frequency stimulations (HFS) of biphasic pulses have been used in clinic stimulations, such as deep brain stimulation (DBS), to minimize the risk of tissue damages caused by the electrical stimulations. However, HFS sequences of monophasic pulses have often been used in animal experiments for studying neuronal responses to the stimulations. It is not clear yet what the differences of the neuronal responses to the HFS of monophasic pulses from the HFS of biphasic pulses are. Methods To investigate the neuronal responses to the two types of pulses, orthodromic-HFS (O-HFS) and antidromic-HFS (A-HFS) of biphasic and monophasic pulses (1-min) were delivered by bipolar electrodes, respectively, to the Schaffer collaterals (i.e., afferent fibers) and the alveus fibers (i.e., efferent fibers) of the rat hippocampal CA1 region in vivo. Evoked population spikes of CA1 pyramidal neurons to the HFSs were recorded in the CA1 region. In addition, single pulses of antidromic- and orthodromic-test stimuli were applied before and after HFSs to evaluate the baseline and the recovery of neuronal activity, respectively. Results Spreading depression (SD) appeared during sequences of 200-Hz monophasic O-HFS with a high incidence (4/5), but did not appear during corresponding 200-Hz biphasic O-HFS (0/6). A preceding burst of population spikes appeared before the SD waveforms. Then, the SD propagated slowly, silenced neuronal firing temporarily and resulted in partial recovery of orthodromically evoked population spikes (OPS) after the end of O-HFS. No SD events appeared during the O-HFS with a lower frequency of 100 Hz of monophasic or biphasic pulses (0/5 and 0/6, respectively), neither during the A-HFS of 200-Hz pulses (0/9). The antidromically evoked population spikes (APS) after 200-Hz biphasic A-HFS recovered to baseline level within ~ 2 min. However, the APS only recovered partially after the 200-Hz A-HFS of monophasic pulses. Conclusions The O-HFS with a higher frequency of monophasic pulses can induce the abnormal neuron activity of SD and the A-HFS of monophasic pulses can cause a persisting attenuation of neuronal excitability, indicating neuronal damages caused by monophasic stimulations in brain tissues. The results provide guidance for proper stimulation protocols in clinic and animal experiments.

Low, but Not High, Doses of Copper Sulfate Impair Synaptic Plasticity in the Hippocampal CA1 Region In Vivo

2018 ◽  
Vol 185 (1) ◽  
pp. 143-147 ◽  
Author(s):  
Abolfazl Jand ◽  
Mohammad Reza Taheri-nejad ◽  
Masoumeh Mosleh ◽  
Mohammad Reza Palizvan
Keyword(s):  
Synaptic Plasticity ◽  
Copper Sulfate ◽  
Ca1 Region ◽  
Hippocampal Ca1 Region ◽  
Hippocampal Ca1 ◽  
High Doses

scholarly journals Chewing Prevents Stress-Induced Hippocampal LTD Formation and Anxiety-Related Behaviors: A Possible Role of the Dopaminergic System

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Yumie Ono ◽  
So Koizumi ◽  
Minoru Onozuka
Keyword(s):  
Dopaminergic System ◽  
Ventral Hippocampus ◽  
Male Rats ◽  
Ca1 Region ◽  
Hippocampal Ca1 Region ◽  
Hippocampal Ca1 ◽  
Plus Maze ◽  
And Control

The present study examined the effects of chewing on stress-induced long-term depression (LTD) and anxiogenic behavior. Experiments were performed in adult male rats under three conditions: restraint stress condition, voluntary chewing condition during stress, and control condition without any treatments except handling. Chewing ameliorated LTD development in the hippocampal CA1 region. It also counteracted the stress-suppressed number of entries to the center region of the open field when they were tested immediately, 30 min, or 60 min after restraint. At the latter two poststress time periods, chewing during restraint significantly increased the number of times of open arm entries in the elevated plus maze, when compared with those without chewing. Thein vivomicrodialysis further revealed that extracellular dopamine concentration in the ventral hippocampus, which is involved in anxiety-related behavior, was significantly greater in chewing rats than in those without chewing from 30 to 105 min after stress exposure. Development of LTD and anxiolytic effects ameliorated by chewing were counteracted by administering the D1 dopamine receptor antagonist SCH23390, which suggested that chewing may activate the dopaminergic system in the ventral hippocampus to suppress stress-induced anxiogenic behavior.

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