Vestibular stimulation enhances hippocampal long-term potentiation via activation of cholinergic septohippocampal cells

Reduction of long-term potentiation at Schaffer collateral-CA1 synapses in the rat hippocampus at the acute stage of vestibular compensation

“…For example, a transient inactivation of vestibular hair cells by injection of lidocaine in the middle ear causes severe reduction in the firing rates of place cells and an absence of theta rhythms (4~10 Hz) in the CA1 area over 3 days after the injection [1920]. Otherwise, vestibular activation by passive whole-body rotation results in a continuous induction of the theta rhythm and alteration of fEPSPs amplitudes in the CA1 area [16]. Electrical stimulation of the medial vestibular nucleus in the brainstem increases firing rates of CA1 complex spike cells corresponding anatomically to pyramidal cells in rats [21].…”

“…A previous experimental study observed no significant changes in LTP induction in the CA1 area and dentate gyrus of awake and anesthetized rats 1~7 months following bilateral labyrinthectomy [15]. Transient activation of the peripheral vestibular system by passive whole-body rotation enhances LTP via activation of cholinergic septohippocampal cells in the CA1 area in freely behaving rats [16]. Therefore, as far as we know, we report here for first time the observation of reduced LTP induction, indicating impaired synaptic plasticity in the CA1 area following the removal of peripheral vestibular end organs.…”

“…Bilateral labyrinthectomy did not affect the induction and maintenance of LTP in the hippocampal CA1 area in rats 6 weeks after surgery [15]. The induction rate of LTP in the CA1 area by passive whole-body rotation was higher than by immobility in the CA1 area of behaving rats [16]. However, it has not been demonstrated how UL affects induction of LTP in the CA1.…”

Hippocampal and striatal M1‐muscarinic acetylcholine receptors are down‐regulated following bilateral vestibular loss in rats

“…While increases in ACh release have been found in the hippocampus during electrical stimulation of the vestibular system (Horii et al, ), and LTP induced by rotation (i.e., natural vestibular stimulation) has been shown to be abolished by pre‐treatment with the muscarinic ACh receptor antagonist, atropine (Tai and Leung, ), no study to date has examined the effect of complete BVL on the hippocampal or striatal cholinergic receptors. The complete loss of vestibular input is hypothesized to have a significant effect on the density of hippocampal and striatal muscarinic ACh receptors.…”

Beneficial effects of vestibular stimulation on learning and memory: an overview

“…16 So vestibular atrophy primarily affects these cells and impairs the generation of theta rhythm by place cells. 17 Patients with chronic bilateral vestibular deficits suffers bilateral hippocampal atrophy and spatial memory impairment. vestibular stimulation enhances Long Term Potentiation (LTP) in CA1 area of hippocampus especially by activating septohippocampal cells and causes long-lasting increase in synaptic transmission of Ach.…”