Research Projects

Project Summary A novel technique called transcranial current stimulation (TCS) creates small electrical fields in the brain through electrodes placed on the scalp. As a method for neuromodulation, TCS carries with it many practical benefits: it is portable (battery-operated), inexpensive, and easily deployable in the clinic and at home. Due to this simplicity and apparent versatility there has been an explosion in the number of studies currently underway using either direct or alternating transcranial currents (over 500 clinical trials are listed with clinicaltrials.gov).

Project Summary/Abstract Memory impairment occurs in a variety of neuropsychiatric conditions (e.g., depression and schizophrenia) and in many neurologic disorders (e.g., neurodegenerative disease and brain injury), often with devastating consequences for life quality. The goal of this project is to determine optimal dosing parameters for a new procedure involving the noninvasive enhancement of human hippocampal-cortical brain networks that critically support memory.

1. Project Summary/Abstract Electroconvulsive therapy (ECT) remains the gold-standard treatment for patients with depressive episodes. During a typical four-week ECT series, most depressive episodes remit, and formerly suicidal or psychotically depressed patients will resume their premorbid levels of functioning. Independent of the antidepressant effect of ECT, many patients experience debilitating but transient cognitive effects such as attention and memory def- icits.

ABSTRACT Repetitive transcranial magnetic stimulation (rTMS) is an emerging technology for the treatment of neurological and psychiatric illnesses. Recent interest has shifted to the cerebellum, where initial promising therapeutic investigations have been made disease such as schizophrenia and ataxia. Despite these developments, the understanding of which parameters are best suited to stimulate the cerebellum remains a mystery.

ABSTRACT Stroke is the leading cause of disability in the United States, with approximately 700,000 new cases per year. Disability from upper limb impairment depends primarily on loss of hand function and finger dexterity. Despite advances in task-specific training for the upper limb, a large number of stroke patients do not regain full function of their hand. Somatosensory peripheral nerve stimulation (PNS) is a promising approach to target recovery of hand motor function in stroke patients.

Research investigating the use of noninvasive electrical stimulation (e.g., transcranial direct current stimulation (tDCS)), for neurologic and psychiatric disorders has provided compelling evidence that such stimulation can modulate behavior and cognition, and even facilitate recovery of function after focal brain injury, with effects typically outlasting the stimulation period.

Abstract Micro-magnetic stimulation (μMS) is an emerging technology with a great promise to revolutionize therapeutic stimulation of human nervous system. Originally developed to stimulation single neurons, μMS uses ultra- conductive neuron-size coils that are capable of carrying current pulses large enough to elicit neural activation by means of magnetic induction.

Abstract Ultrasound (US) neuromodulation has received increased attention in recent years due to its unique ability to non-invasively activate and inhibit neurons. However, the mechanisms of US neuromodulation are not fully understood, and little is known about the optimal parameters that elicit neuromodulation. In this proposal, we will test a recently proposed model of US neuromodulation at the cellular level using patch clamp methods on pyramidal and interneurons, which have differing characteristics that we hypothesize will cause them to respond differently to US.

Project Summary / Abstract In an exciting era of growth in the use of non-invasive brain stimulation, new methods and applications are being disseminated widely with an increasing number of FDA approvals and equipment designed to probe or modulate the brain in fascinating new ways. The problem with this growing enthusiasm is that there are too few studies that have evaluated how tools such as transcranial magnetic stimulation (TMS) induce functional activation throughout a human brain, especially outside of the motor system.

PROJECT SUMMARY - UNIVERSITY OF NORTH CAROLINA-CHAPEL HILL, FROHLICH The alpha oscillation is a thalamo-cortical rhythm (8-12 Hz) that serves important functional roles in cognition and behavior. Transcranial alternating current stimulation (tACS) has been shown to alter cortical alpha oscillations and associated cognitive function in healthy human participants. However, it remains unclear how tACS engages and modulates thalamo-cortical oscillations as a function of stimulation dose (frequency, amplitude, and duration).