Mark S George

Medical University of South Carolina | MUSC · Department of Psychiatry and Behavioral Sciences

Surgical techniques targeting behavioral disorders date back thousands of years. In this review, the authors discuss the history of neurosurgery for psychiatric disorders, starting with trephination in the Stone Age, progressing through the fraught practice of prefrontal lobotomy, and ending with modern neurosurgical techniques for treating psychia...

Background: Major depressive disorder (MDD) can benefit from novel interventions and personalization. Deep transcranial magnetic stimulation (Deep TMS) targeting the lateral prefrontal cortex (LPFC) using the H1 Coil, was FDA-cleared for treatment of MDD, however recent preliminary data indicate that targeting medial prefrontal cortex (MPFC) using...

Background: Post-stroke depression (PSD) occurs in approximately one-third of chronic stroke survivors. Although pharmacotherapy reduces depressive symptoms, side effects are common and stroke survivors have increased likelihood of multimorbidity and subsequent polypharmacy. Thus, alternative non-pharmacological treatments are needed. Combining tw...

Abstract Transcranial direct current stimulation (tDCS) is a widely used noninvasive brain stimulation technique with mixed results to date. A potential solution is to apply more efficient stimulation to ensure that each participant receives sufficient cortical activation. In this four-part study, we used electric field (E-field) modeling to system...

Background: Military service members are at increased risk for mental health issues and comorbidity with mild traumatic brain injury (mTBI) is common. Largely overlapping symptoms between conditions suggest a shared pathophysiology. The present work investigates the associations between white matter microstructure, psychological functioning, and s...

Purpose: Transcutaneous auricular vagus nerve stimulation (taVNS) is a non-invasive neuromodulation technique that may improve oromotor skills when paired with feeding in at-risk infants, but effects on other motor function and how motor function relates to white matter (WM) microstructure are unknown. Methods: In this prospective study, infants...

Background Although the coronavirus disease 19 (COVID-19) pandemic has now impacted the world for over two years, the persistent secondary neuropsychiatric effects are still not fully understood. These “long COVID” symptoms, also referred to as post-acute sequelae of SARS-CoV-2 infection (PASC), can persist for months after infection without any ef...

Background: Researchers and clinicians have traditionally relied on elastic caps with markings to reposition the transcranial magnetic stimulation (TMS) coil between trains and sessions. Newer neuronavigation technology co-registers the patient's head and structural magnetic resonance imaging (MRI) scan, providing the researcher with real-time fee...

Background: Smoking cessation represents a significant opportunity to improve cancer survival rates, reduces the risk of cancer treatment complications, and improves quality of life. However, about half of cancer patients who smoke continue to smoke despite the availability of several treatments. Previous studies demonstrate that repetitive transc...

Patients with depression who ruminate repeatedly focus on depressive thoughts; however, there are two cognitive subtypes of rumination, reflection and brooding, each associated with different prognoses. Reflection involves problem-solving and is associated with positive outcomes, whereas brooding involves passive, negative, comparison with other pe...

Background Although the coronavirus disease 19 (COVID-19) pandemic has now impacted the world for over two years, the persistent secondary neuropsychiatric effects are still not fully understood. These “long COVID” symptoms, also referred to as post-acute sequelae of SARS-CoV-2 infection (PASC), can persist for months after infection without any ef...

Background Accelerated transcranial magnetic stimulation (aTMS) is an emerging delivery schedule of repetitive TMS (rTMS). TMS is “accelerated” by applying two or more stimulation sessions within a day. This three-part review comprehensively reports the safety/tolerability, efficacy, and stimulation parameters affecting response across disorders....

Background Findings from correlative neuroimaging studies link increased frontoparietal network (FPN) activation and default mode network (DMN) deactivation to enhanced high cognitive demand processing. To causally investigate FPN-DMN contributions to high cognitive demand processing, the current interleaved TMS-fMRI study simultaneously manipulate...

OBJECTIVES/GOALS: Neonatal hypoxic-ischemic encephalopathy (HIE) is an acute neurologic syndrome where decreased blood flow and oxygen to the brain causes acute and chronic brain dysfunction. The only proven neuroprotective intervention for HIE is hypothermia treatment started within 6 hours of birth and 50% of survivors have long-term deficits. ME...

Mild Traumatic brain injury (mTBI) is a signature wound in military personnel, and repetitive mTBI has been linked to age-related neurogenerative disorders that affect white matter (WM) in the brain. However, findings of injury to specific WM tracts have been variable and inconsistent. This may be due to the heterogeneity of mechanisms, etiology, a...

Background Smoking cessation represents a significant opportunity to improve cancer survival rates, reduce the risk of cancer treatment complications, and improve quality of life. However, about half of cancer patients who smoke continue to smoke despite the availability of several treatments. Previous studies demonstrate that repetitive transcrani...

BACKGROUND The communication through coherence model posits that brain rhythms are synchronized across different frequency bands and that effective connectivity strength between interacting regions depends on their phase relation. Evidence to support the model comes mostly from electrophysiological recordings in animals while evidence from human da...

Background and Objective: We aim to assess the cortical excitability under three montages with single session of transcranial direct current stimulation (tDCS) at 4 mA on ischemic stroke patients. Methods: Adult subjects with first-ever unilateral ischemic stroke ≥6 months and inducible motor evoked potentials (MEP) underwent 3 sessions (washed out...

Background Transcranial magnetic stimulation (TMS) is a non-invasive neuromodulation modality that can treat depression, obsessive-compulsive disorder, or help smoking cessation. Research suggests that timing the delivery of TMS relative to an endogenous brain state may affect efficacy and short-term brain dynamics. Objective To investigate whethe...

(Appeared originally in Brain Stimulation 2020; 13:1805-1812) Reprinted with permission from Elsevier.

(Appeared originally in Brain Stimulation 2018; 11:492-500) Reprinted with permission from Elsevier.

The fields of Neurobiology and Neuromodulation have never been closer. Consequently, the phrase “synaptic plasticity” has become very familiar to non-basic scientists, without actually being very familiar. We present the “Story of the AMPA receptor,” an easy-to-understand “10,000 ft” narrative overview of synaptic plasticity, oriented toward the br...

The final chapter of this book addresses plasticity in the setting of treating psychiatric disorders. This chapter largely focuses on the treatment of depression and reviews the established antidepressant brain stimulation treatments, focusing on plasticity and maladaptive plasticity. Depression is a unique neuropsychiatric disease in that the brai...

Damage to specific brain circuits can cause specific neuropsychiatric symptoms. Therapeutic stimulation to these same circuits may modulate these symptoms. To determine whether these circuits converge, we studied depression severity after brain lesions (n = 461, five datasets), transcranial magnetic stimulation (n = 151, four datasets) and deep bra...

Transcranial direct current stimulation (tDCS) is a widely used noninvasive brain stimulation technique with mixed results and no FDA-approved therapeutic indication to date. So far, thousands of published tDCS studies have placed large scalp electrodes directly over the intended brain target and delivered the same stimulation intensity to each per...

Background The efficacy of repetitive transcranial magnetic stimulation (rTMS) for depression may vary depending on the subregion stimulated within the dorsolateral prefrontal cortex (DLPFC). Clinical TMS typically uses scalp-based landmarks for DLPFC targeting, rather than individualized MRI guidance. Objective In rTMS patients, determine the bra...

Introduction: Coronavirus disease of 2019 (COVID-19) can enter and directly infect the brain, with myriad neurologic and psychiatric problems. After recovery from the acute infection, many patients struggle with residual neuropsychiatric symptoms (called Long Covid), including fatigue, anxiety and depression. Transcutaneous Auricular Vagus Nerve St...

Background: Repetitive transcranial magnetic stimulation (TMS) is an evidence-based treatment for pharmacoresistant major depressive disorder (MDD), however, the evidence in veterans has been mixed. To this end, VA implemented a nationwide TMS program that included evaluating clinical outcomes within a naturalistic design. TMS was hypothesized to...

Repetitive transcranial magnetic stimulation (rTMS) is a non-invasive brain stimulation method increasingly used to treat psychiatric disorders, primarily depression. Initial studies suggest that rTMS may help to treat addictions, but evaluation in multicenter randomized controlled trials (RCTs) is needed. We conducted a multicenter double-blind RC...

Despite more than 25 years of research establishing the antidepressant efficacy of repetitive transcranial magnetic stimulation, there remains uncertainty about the depth and breadth of this evidence base, resulting in confusion as to where repetitive transcranial magnetic stimulation fits in the therapeutic armamentarium in the management of patie...

Objective In this study, we reexamined the use of 120% resting motor threshold (rMT) dosing for transcranial magnetic stimulation (TMS) over the left dorsolateral prefrontal cortex (DLPFC) using electric field modeling. Methods We computed electric field models in 38 tobacco use disorder (TUD) participants to compare figure-8 coil induced electric...

Orienting attention in the space around us is a fundamental prerequisite for willed actions. On Earth, at 1 g, orienting attention requires the integration of vestibular signals and vision, although the specific vestibular contribution to voluntary and automatic components of visuospatial attention remains largely unknown. Here, we show that unweig...