Pharmacological Mechanisms of Low-intensity Focused Ultrasound for Motor Cortex Neuroplasticity
Status:
Recruiting
Trial end date:
2026-05-01
Target enrollment:
Participant gender:
Summary
Low-intensity focused ultrasound (LIFUS) has been shown to be an effective and safe
non-invasive brain stimulation technique, capable of reaching greater brain depth and a
greater spatial resolution than other brain stimulation tools. Its use as a potential
clinical tool for treatment of neurological disorders is reliant on an understanding of its
mechanisms of action. Although it has been shown to induce immediate (online) and prolonged
(offline) changes in plasticity in the motor cortex, researchers have not studied its effects
on neurotransmitter receptors and ion channels responsible for neuronal signaling in humans.
The purpose of this study is to explore the effects of online and offline LIFUS stimulation
in tandem with administration of various brain-active drugs, to elucidate the effects of this
technique on specific cortical receptors and channels. 20 healthy, screened subjects will be
recruited to participate in 5 sessions in-lab. Each session will represent the double-blinded
administration of four known and studied pharmacological agents known to safely induce
changes in the motor cortex, as well as a placebo. Investigators will use carbamazepine
(sodium channel blocker), lorazepam (GABAA positive allosteric modulator), nimodipine
(calcium channel blocker), and dextromethorphan (glutamate N-Methyl-D-aspartate receptor
antagonist). Single- and paired-pulse transcranial magnetic stimulation (TMS) measures will
be recorded for online LIFUS before and after drug intervention, and induction of offline
LIFUS during placebo will be compared with its induction following the various drug
interventions. Investigators predict that due to the differential effects of online and
offline LIFUS on motor parameters, the mechanisms in which it alters the receptors and
channels of interest will also be deferentially modulated.