Left frontal pole theta burst stimulation decreases orbitofrontal and insula activity in cocaine users and alcohol users

Instantaneous effects of prefrontal transcranial magnetic stimulation on brain oxygenation: A systematic review

This systematic review investigates how prefrontal transcranial magnetic stimulation (TMS) immediately influences neuronal excitability based on oxygenation changes measured by functional magnetic resonance imaging (fMRI) or functional near-infrared spectroscopy (fNIRS). A thorough understanding of TMS-induced excitability changes may enable clinicians to adjust TMS parameters and optimize treatment plans proactively. Five databases were searched for human studies evaluating brain excitability using concurrent TMS/fMRI or TMS/fNIRS. Thirty-seven studies (13 concurrent TMS/fNIRS studies, 24 concurrent TMS/fMRI studies) were included in a qualitative synthesis. Despite methodological inconsistencies, a distinct pattern of activated nodes in the frontoparietal central executive network, the cingulo-opercular salience network, and the default-mode network emerged. The activated nodes included the prefrontal cortex (particularly dorsolateral prefrontal cortex), insula cortex, striatal regions (especially caudate, putamen), anterior cingulate cortex, and thalamus. High-frequency repetitive TMS most consistently induced expected facilitatory effects in these brain regions. However, varied stimulation parameters (e.g., intensity, coil orientation, target sites) and the inter- and intra-individual variability of brain state contribute to the observed heterogeneity of target excitability and co-activated regions. Given the considerable methodological and individual variability across the limited evidence, conclusions should be drawn with caution.

Pilot study with randomised control of dual site theta burst transcranial magnetic stimulation (TMS) for methamphetamine use disorder: a protocol for the TARTAN study

BACKGROUND

Transcranial magnetic stimulation (TMS) (including the theta burst stimulation (TBS) form of TMS used in this study) is a non-invasive means to stimulate nerve cells in superficial areas of the brain. In recent years, there has been a growth in the application of TMS to investigate the modulation of neural networks involved in substance use disorders. This study examines the feasibility of novel TMS protocols for the treatment of methamphetamine (MA) use disorder in an ambulatory drug and alcohol treatment setting.

METHODS

Thirty participants meeting the criteria for moderate to severe MA use disorder will be recruited in community drug and alcohol treatment settings and randomised to receive active TMS or sham (control) intervention. The treatment is intermittent TBS (iTBS) applied to the left dorsolateral prefrontal cortex (DLPFC), then continuous TBS (cTBS) to the left orbitofrontal cortex (OFC). Twelve sessions are administered over 4 weeks with opt-in weekly standardized cognitive behaviour therapy (CBT) counselling and a neuroimaging sub-study offered to participants. Primary outcomes are feasibility measures including recruitment, retention and acceptability of the intervention. Secondary outcomes include monitoring of safety and preliminary efficacy data including changes in substance use, cravings (cue reactivity) and cognition (response inhibition).

DISCUSSION

This study examines shorter TBS protocols of TMS for MA use disorder in real-world drug and alcohol outpatient settings where withdrawal and abstinence from MA, or other substances, are not eligibility requirements. TMS is a relatively affordable treatment and staff of ambulatory health settings can be trained to administer TMS. It is a potentially scalable and translatable treatment for existing drug and alcohol clinical settings. TMS has the potential to provide a much-needed adjuvant treatment to existing psychosocial interventions for MA use disorder. A limitation of this protocol is that the feasibility of follow-up is only examined at the end of treatment (4 weeks).

TRIAL REGISTRATION

Australia New Zealand Clinical Trial Registry ACTRN12622000762752. Registered on May 27, 2022, and retrospectively registered (first participant enrolled) on May 23, 2022, with protocol version 7 on February 24, 2023.

Intermittent theta burst stimulation and functional connectivity in people living with HIV/AIDS who smoke tobacco cigarettes: a preliminary pilot study

Background

People living with HIV (PLWHA) smoke at three times the rate of the general population and respond poorly to cessation strategies. Previous studies examined repetitive transcranial magnetic stimulation (rTMS) over left dorsolateral prefrontal cortex (L. dlPFC) to reduce craving, but no studies have explored rTMS among PLWHA who smoke. The current pilot study compared the effects of active and sham intermittent theta-burst stimulation (iTBS) on resting state functional connectivity (rsFC), cigarette cue attentional bias, and cigarette craving in PLWHA who smoke.

Methods

Eight PLWHA were recruited (single-blind, within-subject design) to receive one session of iTBS (n=8) over the L. dlPFC using neuronavigation and, four weeks later, sham iTBS (n=5). Cigarette craving and attentional bias assessments were completed before and after both iTBS and sham iTBS. rsFC was assessed before iTBS (baseline) and after iTBS and sham iTBS.

Results

Compared to sham iTBS, iTBS enhanced rsFC between the L. dlPFC and bilateral medial prefrontal cortex and pons. iTBS also enhanced rsFC between the right insula and right occipital cortex compared to sham iTBS. iTBS also decreased cigarette craving and cigarette cue attentional bias.

Conclusion

iTBS could potentially offer a therapeutic option for smoking cessation in PLWHA.

Individualized, connectome-based, non-invasive stimulation of OCD deep-brain targets: A proof-of-concept

Treatment-resistant obsessive-compulsive disorder (OCD) generally improves with deep-brain stimulation (DBS), thought to modulate neural activity at both the implantation site and in connected brain regions. However, its invasive nature, side-effects, and lack of customization, make non-invasive treatments preferable. Harnessing the established remote effects of cortical transcranial magnetic stimulation (TMS), connectivity-based approaches have emerged for depression that aim at influencing distant regions connected to the stimulation site. We here investigated whether effective OCD DBS targets (here subthalamic nucleus [STN] and nucleus accumbens [NAc]) could be modulated non-invasively with TMS. In a proof-of-concept study with nine healthy individuals, we used 7T magnetic resonance imaging (MRI) and probabilistic tractography to reconstruct the fiber tracts traversing manually segmented STN/NAc. Two TMS targets were individually selected based on the strength of their structural connectivity to either the STN, or both the STN and NAc. In a sham-controlled, within-subject cross-over design, TMS was administered over the personalized targets, located around the precentral and middle frontal gyrus. Resting-state functional 3T MRI was acquired before, and at 5 and 25 min after stimulation to investigate TMS-induced changes in the functional connectivity of the STN and NAc with other regions of the brain. Static and dynamic seed-to-voxel correlation analyses were conducted. TMS over both targets was able to modulate the functional connectivity of the STN and NAc, engaging both overlapping and distinct regions, and unfolding following different temporal dynamics. Given the relevance of the engaged connected regions to OCD pathology, we argue that a personalized, connectivity-based procedure is worth investigating as potential treatment for refractory OCD.

A systematic review and meta-analysis of neuromodulation therapies for substance use disorders

While pharmacological, behavioral and psychosocial treatments are available for substance use disorders (SUDs), they are not always effective or well-tolerated. Neuromodulation (NM) methods, including repetitive transcranial magnetic stimulation (rTMS), transcranial direct current stimulation (tDCS) and deep brain stimulation (DBS) may address SUDs by targeting addiction neurocircuitry. We evaluated the efficacy of NM to improve behavioral outcomes in SUDs. A systematic literature search was performed on MEDLINE, PsychINFO, and PubMed databases and a list of search terms for four key concepts (SUD, rTMS, tDCS, DBS) was applied. Ninety-four studies were identified that examined the effects of rTMS, tDCS, and DBS on substance use outcomes (e.g., craving, consumption, and relapse) amongst individuals with SUDs including alcohol, tobacco, cannabis, stimulants, and opioids. Meta-analyses were performed for alcohol and tobacco studies using rTMS and tDCS. We found that rTMS reduced substance use and craving, as indicated by medium to large effect sizes (Hedge's g > 0.5). Results were most encouraging when multiple stimulation sessions were applied, and the left dorsolateral prefrontal cortex (DLPFC) was targeted. tDCS also produced medium effect sizes for drug use and craving, though they were highly variable and less robust than rTMS; right anodal DLPFC stimulation appeared to be most efficacious. DBS studies were typically small, uncontrolled studies, but showed promise in reducing misuse of multiple substances. NM may be promising for the treatment of SUDs. Future studies should determine underlying neural mechanisms of NM, and further evaluate extended treatment durations, accelerated administration protocols and long-term outcomes with biochemical verification of substance use.

Converging Evidence for Frontopolar Cortex as a Target for Neuromodulation in Addiction Treatment

Noninvasive brain stimulation technologies such as transcranial electrical and magnetic stimulation (tES and TMS) are emerging neuromodulation therapies that are being used to target the neural substrates of substance use disorders. By the end of 2022, 205 trials of tES or TMS in the treatment of substance use disorders had been published, with heterogeneous results, and there is still no consensus on the optimal target brain region. Recent work may help clarify where and how to apply stimulation, owing to expanding databases of neuroimaging studies, new systematic reviews, and improved methods for causal brain mapping. Whereas most previous clinical trials targeted the dorsolateral prefrontal cortex, accumulating data highlight the frontopolar cortex as a promising therapeutic target for transcranial brain stimulation in substance use disorders. This approach is supported by converging multimodal evidence, including lesion-based maps, functional MRI-based maps, tES studies, TMS studies, and dose-response relationships. This review highlights the importance of targeting the frontopolar area and tailoring the treatment according to interindividual variations in brain state and trait and electric field distribution patterns. This converging evidence supports the potential for treatment optimization through context, target, dose, and timing dimensions to improve clinical outcomes of transcranial brain stimulation in people with substance use disorders in future clinical trials.

Increasing striatal dopamine release through repeated bouts of theta burst transcranial magnetic stimulation of the left dorsolateral prefrontal cortex. A 18F-desmethoxyfallypride positron emission tomography study

Introduction

Transcranial Magnetic Stimulation (TMS) can modulate fronto-striatal connectivity in the human brain. Here Positron Emission Tomography (PET) and neuro-navigated TMS were combined to investigate the dynamics of the fronto-striatal connectivity in the human brain. Employing 18F-DesmethoxyFallypride (DMFP) - a Dopamine receptor-antagonist - the release of endogenous dopamine in the striatum in response to time-spaced repeated bouts of excitatory, intermittent theta burst stimulation (iTBS) of the Left-Dorsolateral Prefrontal Cortex (L-DLPFC) was measured.

Methods

23 healthy participants underwent two PET sessions, each one with four blocks of iTBS separated by 30 minutes: sham (control) and verum (90% of individual resting motor threshold). Receptor Binding Ratios were collected for sham and verum sessions across 37 time frames (about 130 minutes) in striatal sub-regions (Caudate nucleus and Putamen).

Results

Verum iTBS increased the dopamine release in striatal sub-regions, relative to sham iTBS. Dopamine levels in the verum session increased progressively across the time frames until frame number 28 (approximately 85 minutes after the start of the session and after three iTBS bouts) and then essentially remained unchanged until the end of the session.

Conclusion

Results suggest that the short-timed iTBS protocol performed in time-spaced blocks can effectively induce a dynamic dose dependent increase in dopaminergic fronto-striatal connectivity. This scheme could provide an alternative to unpleasant and distressing, long stimulation protocols in experimental and therapeutic settings. Specifically, it was demonstrated that three repeated bouts of iTBS, spaced by short intervals, achieve larger effects than one single stimulation. This finding has implications for the planning of therapeutic interventions, for example, treatment of major depression.

A preliminary randomized controlled trial of repetitive transcranial magnetic stimulation applied to the left dorsolateral prefrontal cortex in treatment seeking participants with cannabis use disorder

BACKGROUND

Cannabis use disorder (CUD) is a common and consequential disorder. When applied to the dorsolateral prefrontal cortex (DLPFC), repetitive transcranial magnetic stimulation (rTMS) reduces craving across substance use disorders and may have therapeutic clinical effects when applied in serial-sessions. The present study sought to preliminarily determine whether serial-sessions of rTMS applied to the DLPFC had a therapeutic effect in CUD.

METHODS

This study was a two-site, phase-2, double-blind, randomized-controlled-trial. Seventy-two treatment-seeking participants (37.5% Women, mean age 30.2±9.9SD) with ≥moderate-CUD were randomized to active or sham rTMS (Beam-F3, 10Hz, 20-total-sessions, two-sessions-per-visit, two-visits-per-week, with cannabis cues) while undergoing a three-session motivational enhancement therapy intervention. The primary outcome was the change in craving between pre- and post- treatment (Marijuana Craving Questionnaire Short-Form-MCQ-SF). Secondary outcomes included the number of weeks of abstinence and the number of days-per-week of cannabis use during 4-weeks of follow-up.

RESULTS

There were no significant differences in craving between conditions. Participants who received active-rTMS reported numerically, but not significantly, more weeks of abstinence in the follow-up period than those who received sham-rTMS (15.5%-Active; 9.3%-Sham; rate ratio = 1.66 [95% CI: 0.84, 3.28]; p=0.14). Participants who received active-rTMS reported fewer days-per-week of cannabis use over the final two-weeks of the follow-up period than those receiving sham-rTMS (Active vs. Sham: -0.72; Z=-2.33, p=0.02).

CONCLUSIONS

This trial suggests rTMS is safe and feasible in individuals with CUD and may have a therapeutic effect on frequency of cannabis use, though further study is needed with additional rTMS-sessions and a longer follow-up period.

A pilot, randomized clinical trial: Left dorsolateral prefrontal cortex intermittent theta burst stimulation improves treatment outcomes in veterans with alcohol use disorder

BACKGROUND

Transcranial magnetic stimulation (TMS) offers a promising treatment avenue to modulate brain function in alcohol use disorder (AUD). To the best of our knowledge, this pilot study is the first randomized, double-blind, sham-controlled trial to deliver intermittent theta burst stimulation to the left dorsolateral prefrontal cortex (DLPFC) among US veterans with AUD. We hypothesized that 20 sessions of real TMS are tolerable and feasible. As a secondary line of inquiry, we hypothesized that, relative to sham TMS, individuals receiving real TMS would experience greater reductions in 6-month relapse rates, anhedonia, and alcohol cue-reactivity.

METHODS

Veterans (n = 17, one woman) were enrolled in a double-blind, sham-controlled trial (2-3 sessions/day; 7-10 days; 600 pulses/session; 20 sessions). Pre- and posttreatment assessments included responses to self-report questionnaires and functional magnetic resonance imaging measures of alcohol cue-reactivity. Alcohol consumption was assessed for 6 months. Linear mixed-effects models were constructed to predict posttreatment craving, mood, and cue-reactivity.

RESULTS

Individuals who received active iTBS (n = 8) were less likely to relapse within 3 months after treatment than the sham-treated group (n = 9) (OR = 12.0). Greater reductions in anhedonia were observed following active iTBS (Cohen's d = -0.59), relative to sham (d = -0.25). Alcohol cue-reactivity was reduced following active iTBS and increased following sham within the left insula (d = -0.19 vs. 0.51), left thalamus (d = -0.28 vs. 0.77), right insula (d = 0.18 vs. 0.52), and right thalamus (d = -0.06 vs. 0.62).

CONCLUSIONS

Relative to sham, we demonstrate that 20 sessions of real left DLPFC iTBS reduced the likelihood of relapse for at least 3 months. The potential utility of this approach is underscored by observed decreases in anhedonia and alcohol cue-reactivity-strong predictors of relapse among veterans. These initial data offer a valuable set of effect sizes to inform future clinical trials in this patient population.

Managing substance use in patients receiving therapeutic repetitive transcranial magnetic stimulation: A scoping review

Repetitive Transcranial Magnetic Stimulation (rTMS) is an invaluable treatment option for neuropsychiatric disorders. Co-occurring recreational and nonmedical substance use can be common in those presenting for rTMS treatment, and it is unknown how it may affect the safety and efficacy of rTMS for the treatment of currently approved neuropsychiatric indications. This scoping review aimed to map the literature on humans receiving rTMS and had a history of any type of substance use. The search identified 274 articles providing information on inclusion/exclusion criteria, withdrawal criteria, safety protocols, type of rTMS and treatment parameters, adverse events and effect on primary outcomes that related to substance use. There are neurophysiological effects of substance use on cortical excitability, although the relevance to clinical rTMS practice is unknown. The current literature supports the safety and feasibility of delivering rTMS to those who have co-occurring neuropsychiatric disorder and substance use. However, specific details on how varying degrees of substance use alters the safety, efficacy, and mechanisms of rTMS remains poorly described.

Connecting the dots: harnessing dual-site transcranial magnetic stimulation to quantify the causal influence of medial frontal areas on the motor cortex

Dual-site transcranial magnetic stimulation has been widely employed to investigate the influence of cortical structures on the primary motor cortex. Here, we leveraged this technique to probe the causal influence of two key areas of the medial frontal cortex, namely the supplementary motor area and the medial orbitofrontal cortex, on primary motor cortex. We show that supplementary motor area stimulation facilitates primary motor cortex activity across short (6 and 8 ms) and long (12 ms) inter-stimulation intervals, putatively recruiting cortico-cortical and cortico-subcortico-cortical circuits, respectively. Crucially, magnetic resonance imaging revealed that this facilitatory effect depended on a key morphometric feature of supplementary motor area: individuals with larger supplementary motor area volumes exhibited more facilitation from supplementary motor area to primary motor cortex for both short and long inter-stimulation intervals. Notably, we also provide evidence that the facilitatory effect of supplementary motor area stimulation at short intervals is unlikely to arise from spinal interactions of volleys descending simultaneously from supplementary motor area and primary motor cortex. On the other hand, medial orbitofrontal cortex stimulation moderately suppressed primary motor cortex activity at both short and long intervals, irrespective of medial orbitofrontal cortex volume. These results suggest that dual-site transcranial magnetic stimulation is a fruitful approach to investigate the differential influence of supplementary motor area and medial orbitofrontal cortex on primary motor cortex activity, paving the way for the multimodal assessment of these fronto-motor circuits in health and disease.

Effects of transcranial magnetic stimulation on cocaine addiction: A systematic review of randomized controlled trials

OBJECTIVE

While pharmacological strategies appear to be ineffective in treating long-term addiction, repetitive transcranial magnetic stimulation (rTMS) is emerging as a promising new tool for the attenuation of craving among multiple substance dependent populations.

METHOD

A systematic review of randomized controlled trials (RCTs) was conducted on the efficacy and tolerability of rTMS in treating cocaine use disorder (CUD). Relevant papers published in English through November 30th 2022 were identified, searching the electronic databases MEDLINE, Embase, PsycINFO and the Cochrane Library.

RESULTS

Eight studies matched inclusion criteria. The best findings were reported by the RCTs conducted at high-frequency (≥5 Hz) multiple sessions of rTMS delivered over the left dorsolateral prefrontal cortex (DLPFC): a significant decrease in self-reported cue-induced cocaine craving and lower cocaine craving scores and a considerable amelioration in the tendency to act rashly under extreme negative emotions (impulsivity) were found in the active group compared to controls.

CONCLUSION

Although still scant and heterogeneous, the strongest evidence so far on the use of rTMS on individuals with CUD support the high frequency stimulation over the left DLPFC as a well tolerated treatment of cocaine craving and impulsivity.

A Preliminary Investigation Of Repetitive Transcranial Magnetic Stimulation Applied To The Left Dorsolateral Prefrontal Cortex In Treatment Seeking Participants With Cannabis Use Disorder

Background

Cannabis use disorder (CUD) is a common and consequential disorder. When applied to the dorsolateral prefrontal cortex (DLPFC), repetitive transcranial magnetic stimulation (rTMS) reduces craving across substance use disorders and may have a therapeutic clinical effect when applied in serial sessions. The present study sought to preliminarily determine whether serial sessions of rTMS applied to the DLPFC had a therapeutic effect in CUD.

Methods

This study was a two-site, phase-2, double-blind, randomized-controlled-trial. Seventy-two treatment-seeking participants (37.5% Women, mean age 30.2±9.9SD) with ≥moderate-CUD were randomized to active or sham rTMS (Beam-F3, 10Hz, 20-total-sessions, with cannabis cues) while undergoing a three-session motivational enhancement therapy intervention. The primary outcome was the change in craving between pre- and post-treatment (Marijuana Craving Questionnaire Short-Form-MCQ-SF). Secondary outcomes included the number of weeks of abstinence and the number of days-per-week of cannabis use during 4-weeks of follow-up.

Results

There were no significant differences in craving between conditions. Participants who received active rTMS reported numerically, but not significantly, more weeks of abstinence in the follow-up period than those who received sham rTMS (15.5%-Active; 9.3%-Sham; rate ratio = 1.66 [95% CI: 0.84, 3.28]; p=0.14). Participants who received active rTMS reported fewer days-per-week of cannabis use over the final two-weeks of the follow-up period (Active vs. Sham: -0.72; Z=-2.33, p=0.02).

Conclusions

This trial suggests rTMS is safe and feasible in individuals with CUD and may have a therapeutic effect on frequency of cannabis use, though further study is needed with additional rTMS-sessions and a longer follow-up period.

Intrusive thinking: Circuit and synaptic mechanisms of a transdiagnostic psychiatric symptom

Spontaneous thought is an adaptive cognitive process that can produce novel and insightful thought sequences useful in guiding future behavior. In many psychiatric disorders, spontaneous thinking becomes intrusive and uncontrolled, and can trigger symptoms such as craving, repetitive negative thinking and trauma-related memories. We link studies using clinical imaging and rodent modeling towards understanding the neurocircuitry and neuroplasticity of intrusive thinking. We propose a framework in which drugs or stress change the homeostatic set point of brain reward circuitry, which then impacts subsequent plasticity induced by drug/stress conditioned cues (metaplastic allostasis). We further argue for the importance of examining not only the canonical pre- and postsynapse, but also the adjacent astroglial protrusions and extracellular matrix that together form the tetrapartite synapse and that plasticity throughout the tetrapartite synapse is necessary for cue-induced drug or stress behaviors. This analysis reveals that drug use or trauma cause long-lasting allostatic brain plasticity that sets the stage for subsequent drug/trauma-associated cues to induce transient plasticity that can lead to intrusive thinking.

Brain stimulation therapeutics

This chapter covers how repetitive transcranial magnetic stimulation (rTMS) or transcranial direct current stimulation (tDCS) presently affects smoking cessation. 14 human studies have examined the efficacy of rTMS on cue craving, cigarette consumption, or smoking cessation using a variety of different coils, locations, and treatment parameters. These studies included 7 randomized-controlled trials (RCT) and 7 experimental studies. Most studies (12/14) reported that rTMS reduced cue-induced craving, 5 showed that it decreased cigarette consumption, and 3/4 reported that multiple sessions of rTMS increased the quit rate. In contrast to rTMS, tDCS has 6 RCT studies, of which only 2 studies reported that tDCS reduced craving, and only 1 reported that it reduced cigarette consumption. Three studies failed to find an effect of tDCS on cravings. No tDCS studies reported changing quitting rates in people who smoke. Despite the early positive results of tDCS on nicotine dependence symptoms, 2 larger RCTs recently failed to find a therapeutic effect of tDCS for smoking cessation. In conclusion, rTMS studies demonstrate that multiple sessions help quit smoking, and it has gained FDA approval for that purpose. However, more studies are needed to examine the effect of tDCS with different treatment parameters.

Computationally Informed Interventions for Targeting Compulsive Behaviors

Compulsive behaviors are central to addiction and obsessive-compulsive disorder and can be understood as a failure of adaptive decision making. Particularly, they can be conceptualized as an imbalance in behavioral control, such that behavior is guided predominantly by learned rather than inferred outcome expectations. Inference is a computational process required for adaptive behavior, and recent work across species has identified the neural circuitry that supports inference-based decision making. This includes the orbitofrontal cortex, which has long been implicated in disorders of compulsive behavior. Inspired by evidence that modulating orbitofrontal cortex activity can alter inference-based behaviors, here we discuss noninvasive approaches to target these circuits in humans. Specifically, we discuss the potential of network-targeted transcranial magnetic stimulation and real-time neurofeedback to modulate the neural underpinnings of inference. Both interventions leverage recent advances in our understanding of the neurocomputational mechanisms of inference-based behavior and may be used to complement current treatment approaches for behavioral disorders.

Optimizing Individual Targeting of Fronto-Amygdala Network with Transcranial Magnetic Stimulation (TMS): Biophysical, Physiological and Behavioral Variations in People with Methamphetamine Use Disorder

Background

Previous studies in people with substance use disorders (SUDs) have implicated both the frontopolar cortex and amygdala in drug cue reactivity and craving, and amygdala-frontopolar coupling is considered a marker of early relapse risk. Accumulating data highlight that the frontopolar cortex can be considered a promising therapeutic target for transcranial magnetic stimulation (TMS) in SUDs. However, one-size-fits-all approaches to TMS targets resulted in substantial variation in both physiological and behavioral outcomes. Individualized TMS approaches to target cortico-subcortical circuits like amygdala-frontopolar have not yet been investigated in SUDs.

Objective

Here, we (1) defined individualized TMS target location based on functional connectivity of the amygdala-frontopolar circuit while people were exposed to drug-related cues, (2) optimized coil orientation based on maximizing electric field (EF) perpendicular to the individualized target, and (3) harmonized EF strength in targeted brain regions across a population.

Method

MRI data including structural, resting-state, and task-based fMRI data were collected from 60 participants with methamphetamine use disorders (MUDs). Craving scores based on a visual analog scale were collected immediately before and after the MRI session. We analyzed inter-subject variability in the location of TMS targets based on the maximum task-based connectivity between the left medial amygdala (with the highest functional activity among subcortical areas during drug cue exposure) and frontopolar cortex using psychophysiological interaction (PPI) analysis. Computational head models were generated for all participants and EF simulations were calculated for fixed vs. optimized coil location (Fp1/Fp2 vs. individualized maximal PPI location), orientation (AF7/AF8 vs. orientation optimization algorithm), and stimulation intensity (constant vs. adjusted intensity across the population).

Results

Left medial amygdala with the highest (mean ± SD: 0.31±0.29) functional activity during drug cue exposure was selected as the subcortical seed region. Amygdala-to-whole brain PPI analysis showed a significant cluster in the prefrontal cortex (cluster size: 2462 voxels, cluster peak in MNI space: [25 39 35]) that confirms cortico-subcortical connections. The location of the voxel with the most positive amygdala-frontopolar PPI connectivity in each participant was considered as the individualized TMS target (mean ± SD of the MNI coordinates: [12.6 64.23 -0.8] ± [13.64 3.50 11.01]). Individual amygdala-frontopolar PPI connectivity in each participant showed a significant correlation with VAS scores after cue exposure (R=0.27, p=0.03). Averaged EF strength in a sphere with r = 5mm around the individualized target location was significantly higher in the optimized (mean ± SD: 0.99 ± 0.21) compared to the fixed approach (Fp1: 0.56 ± 0.22, Fp2: 0.78 ± 0.25) with large effect sizes (Fp1: p = 1.1e-13, Hedges'g = 1.5, Fp2: p = 1.7e-5, Hedges'g = 1.26). Adjustment factor to have identical 1 V/m EF strength in a 5mm sphere around the individualized targets ranged from 0.72 to 2.3 (mean ± SD: 1.07 ± 0.29).

Conclusion

Our results show that optimizing coil orientation and stimulation intensity based on individualized TMS targets led to stronger electric fields in the targeted brain regions compared to a one-size-fits-all approach. These findings provide valuable insights for refining TMS therapy for SUDs by optimizing the modulation of cortico-subcortical circuits.

Evaluating Craving in Alcohol Use Disorder: Psychometric Characteristics of the Craving Typology Questionnaire-15 (CTQ-15)

AIMS

The Craving Typology Questionnaire (CTQ) is a psychometric instrument used to assess alcohol craving in normal controls and subjects with alcohol use disorder (AUD). It allows a dimensional self-rating assessment of craving according to a three-pathway psychobiological model of craving distinguishing craving into a reward, relief and obsessive component. The aim of the present study is to evaluate psychometric properties of the CTQ-15, a revised version of CTQ with 15 items.

METHODS

The CTQ-15 was firstly administered to two groups of control subjects, one (414 subjects) used for the exploratory factor analysis and the other one (415 subjects) for the confirmatory factor analysis. A three-factor model was assessed and compared to alternative models.

RESULTS

The resulting structure was in line with the original scale CTQ. Obsessive craving accounted for 15.20% of the total variance, relief craving for the 13.99% and reward craving for 13.13% of the total variance. The three-factor model (M1) reached good fit indices (CFI = 0.96, TLI = 0.95, RMSEA = 0.06 and SRMR = 0.05) and was significantly better than other alternative models. Reliability showed good internal consistency for each scale, i.e. obsessive craving (α = 0.92), relief craving (α = 0.82) and reward craving (α = 0.81).

CONCLUSIONS

The CTQ-15 proved to be reliable and practical for identifying the three dimensions of craving in clinical practice. Craving plays a crucial role in the mechanisms of dependence and relapse; thus, characterizing the craving can be fundamental to a targeted drug therapy.

Safety and Efficacy of Continuous Theta Burst "Intensive" Stimulation in Acute-Phase Bipolar Depression: A Pilot, Exploratory Study

OBJECTIVES

Repetitive transcranial magnetic stimulation efficacy in unipolar depression is known, but its efficacy in acute-phase bipolar depression is at best modest. Citing differential right dorsolateral prefrontal cortex hyperconnectivity implicated in BD, we aimed to study the effect of novel continuous theta burst stimulation (cTBS) targeting right dorsolateral prefrontal cortex in a randomized rater blinded placebo control design.

MATERIAL AND METHODS

Nineteen patients aged 18 to 59 years (baseline Hamilton Depression Rating Scale [HAM-D] 17 severity score >18) were randomly allocated to active cTBS (n = 11) and sham cTBS (n = 9) groups using block randomization method. They received 15 cTBS sessions (burst of 3 pulses delivered at 50 Hz, repeated every 200 ms at 5 Hz, 600 pulses per session), 3 sessions per day (total of 1800 pulses) for 5 days in a week at 80% resting motor threshold. The HAM-D, Beck Depression Inventory, Hamilton Anxiety Rating Scale, World Health Organization's abbreviated quality of life assessment, and Changes in Sexual Functioning Questionnaire were assessed at baseline, after the last session, and at 2 weeks after repetitive transcranial magnetic stimulation. Intention-to-treat analysis was conducted and missing values (2 patients) were replaced using the last observation carried forward method.

RESULTS

On repeated measures analysis of variance, a significant within-group time effect (from pretreatment to 2 weeks after TBS) for HAM-D ( F = 15.091, P < 0.001), Beck Depression Inventory ( F = 22.376, P < 0.001), Hamilton Anxiety Rating Scale ( F = 18.290, P < 0.001), Changes in Sexual Functioning Questionnaire ( F = 9.281, P = 0.001), and World Health Organization's abbreviated quality of life assessment ( F = 24.008, P < 0.001). The integrity of the blind assessed by the guess matrix was good. When significant between group*time effect was compared, none of the variables retained statistical significance. No major adverse effects were reported, and none of the patients discontinued the trial because of adverse effects.

CONCLUSIONS

Our trial concludes that although safe and well tolerated, the therapeutic efficacy of intensive intermittent TBS in acute-phase bipolar depression is inconclusive. Choice of lower total number to sessions and smaller intersession interval along with small sample size limit the study findings.

Effects of 10 add-on HF-rTMS treatment sessions on alcohol use and craving among detoxified inpatients with alcohol use disorder: a randomized sham-controlled clinical trial

BACKGROUND AND AIMS

Alcohol use disorder (AUD) is a chronic disorder with high relapse rates. There are currently few clinical trials of high frequency repetitive transcranial magnetic stimulation (HF-rTMS) to reduce alcohol use among AUD patients, and results are mixed. The current study tested the effect of 10 add-on sessions of HF-rTMS over the right dorsolateral pre-frontal cortex (DLPFC) on alcohol use and craving.

DESIGN

Single-center, single blind sham-controlled parallel-group RCT (n = 80), with 3 and 6 months follow-up.

SETTING

Clinical treatment center in Amsterdam, the Netherlands.

PARTICIPANTS

Eighty detoxified and abstinent AUD inpatients in clinical treatment (20 females, average age = 44.35 years).

INTERVENTION

Ten sessions of active or sham HF-rTMS (60 10 Hz trains of 5 sec at 110% motor threshold) over the right DLPFC on 10 consecutive work-days.

MEASUREMENTS

The primary outcome measure is the number of abstinent days over 6-month follow-up (FU). Secondary outcome measures are craving over 6-month FU (alcohol urge questionnaire and obsessive-compulsive drinking scale), time to first relapse over 6-month FU and grams of alcohol consumed over 6-month FU. Additional outcome measures: full abstinence over 6-month FU and treatment success over 12-month FU.

FINDINGS

HF-rTMS did not affect the number of abstinent days over 6 months FU [sham = 124 ± 65.9 days, active = 115 ± 69.8 days, difference: 9 days, 95% confidence interval (CI) = Poisson model: 0.578-3.547]. Moreover, HF-rTMS did not affect craving (AUQ/OCDS) (sham = 15.38/5.28, active = 17.48/4.75, differences = 2.1/-0.53, 95% CI mixed-effects model = -9.14 to 2.07/-1.44 to 2.40).

CONCLUSIONS

There was no clear evidence that high-frequency repetitive transcranial magnetic stimulation over the right dorsolateral pre-frontal cortex treatment has a long-term positive effect on alcohol use or craving as add-on treatment for alcohol use disorder. High treatment response at 6-month follow-up could have limited the possibility to find an effect.

Causally mapping human threat extinction relevant circuits with depolarizing brain stimulation methods

Laboratory threat extinction paradigms and exposure-based therapy both involve repeated, safe confrontation with stimuli previously experienced as threatening. This fundamental procedural overlap supports laboratory threat extinction as a compelling analogue of exposure-based therapy. Threat extinction impairments have been detected in clinical anxiety and may contribute to exposure-based therapy non-response and relapse. However, efforts to improve exposure outcomes using techniques that boost extinction - primarily rodent extinction - have largely failed to date, potentially due to fundamental differences between rodent and human neurobiology. In this review, we articulate a comprehensive pre-clinical human research agenda designed to overcome these failures. We describe how connectivity guided depolarizing brain stimulation methods (i.e., TMS and DBS) can be applied concurrently with threat extinction and dual threat reconsolidation-extinction paradigms to causally map human extinction relevant circuits and inform the optimal integration of these methods with exposure-based therapy. We highlight candidate targets including the amygdala, hippocampus, ventromedial prefrontal cortex, dorsal anterior cingulate cortex, and mesolimbic structures, and propose hypotheses about how stimulation delivered at specific learning phases could strengthen threat extinction.

Advances in neuroimaging studies of alcohol use disorder (AUD)

Alcohol use disorder (AUD) is a worldwide problem and the most common substance use disorder. Chronic alcohol consumption may have negative effects on the body, the mind, the family, and even society. With the progress of current neuroimaging methods, an increasing number of imaging techniques are being used to objectively detect brain impairment induced by alcoholism and serve a vital role in the diagnosis, prognosis, and treatment assessment of AUD. This article organizes and analyzes the research on alcohol dependence concerning the main noninvasive neuroimaging methods, structural magnetic resonance imaging, functional magnetic resonance imaging, and electroencephalography, as well as the most common noninvasive brain stimulation - transcranial magnetic stimulation, and intersperses the article with joint intra- and intergroup studies, providing an outlook on future research directions.

Substance Use and Addiction in Athletes: The Case for Neuromodulation and Beyond

Substance use, misuse and use disorders continue to be major problems in society as a whole and athletes are certainly not exempt. Substance use has surrounded sports since ancient times and the pressures associated with competition sometimes can increase the likelihood of use and subsequent misuse. The addiction field as a whole has very few answers to how to prevent and secondarily treat substance use disorders and the treatments overall do not necessarily agree with the role of being an athlete. With concerns for side effects that may affect performance coupled with organizational rules and high rates of recidivism in the general population, newer treatments must be investigated. Prevention strategies must continue to be improved and more systems need to be in place to find and treat any underlying causes leading to these behaviors. This review attempts to highlight some of the data regarding the field of substance misuse and addiction in the athletic population as well as explore possible future directions for treatment including Neuromodulation methods and Ketamine. There is a need for more rigorous, high-quality studies to look at addiction as a whole and in particular how to approach this vulnerable subset of the population.

"Efficacy of intensive bilateral Temporo-Parietal Continuous theta-burst Stimulation for Auditory VErbal hallucinations (TPC-SAVE) in schizophrenia: A randomized sham-controlled trial"☆

Transcranial magnetic stimulation (TMS) is a non-invasive tool that moderates specific brain regions to ameliorate auditory verbal hallucinations (AVH) in schizophrenia. Citing the critical involvement of temporoparietal cortex (TPC) in AVH, our study aimed to evaluate the effect of continuous theta burst stimulation (cTBS) targeting bilateral TPC in schizophrenia subjects with AVH, on a randomized rater blinded placebo control trial. 59 patients were randomly allocated to active and sham groups. They received 20 cTBS sessions (2 per day: first right TPC, then left TPC) 5 days a week for 2 weeks. PANSS (Positive and Negative Syndrome Scale), AVHRS (Auditory vocal hallucination rating scale), PSYRAT-AH (Psychiatric symptoms rating scale- Auditory hallucinations scale), CDSS (Calgary depression scale for schizophrenia), SCoRS (Schizophrenia cognition rating scale) and CGI-S (Clinical global impression-severity) were rated at baseline, immediately post 20th session and 2 weeks post-TBS. 50 patients (25-active, 25-sham) completed the study. Conducting an intention to treat analysis, we found a significant group*time effect for PANSS, AVHRS, PSYRAT-AH, CDSS, SCoRS, CGI-S but when controlled for confounding variables and multiple comparisons, only PANSS-PS (F=26.617, p < 0.001), PANSS-TOTAL (F=23.671, p < 0.001), AVHRS (F=17.779, p < 0.001), PSYRAT-AH (F=11.385, p < 0.001) and CGI-S (F=28.462, p < 0.001) retained significance. We conclude that cTBS over TPC is safe and has efficacy in treating AVH in schizophrenia. Limited sample size and lack of integrity assessment for blinding in the study participants are major limitations of the study.

A transdiagnostic review of safety, efficacy, and parameter space in accelerated transcranial magnetic stimulation

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.

METHODS

We used the PubMed database to identify studies administering aTMS, which we defined as applying at least two rTMS sessions within one day.

RESULTS

Our targeted literature search identified 85 aTMS studies across 18 diagnostic and healthy control groups published from July 2001 to June 2022. Excluding overlapping populations, 63 studies delivered 43,873 aTMS sessions using low frequency, high frequency, and theta burst stimulation in 1543 participants. Regarding safety, aTMS studies had similar seizure and side effect incidence rates to those reported for once daily rTMS. One seizure was reported from aTMS (0.0023% of aTMS sessions, compared with 0.0075% in once daily rTMS). The most common side effects were acute headache (28.4%), fatigue (8.6%), and scalp discomfort (8.3%), with all others under 5%. We evaluated aTMS efficacy in 23 depression studies (the condition with the most studies), finding an average response rate of 42.4% and remission rate of 28.4% (range = 0-90.5% for both). Regarding parameters, aTMS studies ranged from 2 to 10 sessions per day over 2-30 treatment days, 10-640 min between sessions, and a total of 9-104 total accelerated TMS sessions per participant (including tapering sessions). Qualitatively, response rate tends to be higher with an increasing number of sessions per day, total sessions, and total pulses.

DISCUSSION

The literature to date suggests that aTMS is safe and well-tolerated across conditions. Taken together, these early studies suggest potential effectiveness even in highly treatment refractory conditions with the added potential to reduce patient burden while also expediting response time. Future studies are warranted to systematically investigate how key aTMS parameters affect treatment outcome and durability.

Resting-State Functional Connectivity Differences Following Experimental Manipulation of the Orbitofrontal Cortex in Two Directions via Theta-Burst Stimulation

Compulsive behaviors (CBs) have been linked to orbitofrontal cortex (OFC) function in animal and human studies. However, brain regions function not in isolation but as components of widely distributed brain networks—such as those indexed via resting-state functional connectivity (RSFC). Sixty-nine individuals with CB disorders were randomized to receive a single session of neuromodulation targeting the left OFC—intermittent theta-burst stimulation (iTBS) or continuous TBS (cTBS)—followed immediately by computer-based behavioral “habit override” training. OFC seeds were used to quantify RSFC following iTBS and following cTBS. Relative to cTBS, iTBS showed increased RSFC between right OFC (Brodmann’s area 47) and other areas, including dorsomedial prefrontal cortex (dmPFC), occipital cortex, and a priori dorsal and ventral striatal regions. RSFC connectivity effects were correlated with OFC/frontopolar target engagement and with subjective difficulty during habit-override training. Findings help reveal neural network-level impacts of neuromodulation paired with a specific behavioral context, informing mechanistic intervention development.

Left frontal pole repetitive transcranial magnetic stimulation reduces cigarette cue-reactivity in correlation with verbal memory performance

BACKGROUND

Although left frontal pole (LFP) repetitive transcranial magnetic stimulation (rTMS) has been recently investigated for the treatment of different substance use disorders, there is no current evidence that it can effectively influence craving or clinical outcomes in smokers. A single session of 1 Hz rTMS over LFP is proposed to explore short-term effects of this protocol in tobacco use disorder.

METHODS

A pilot randomized trial compared 1 Hz rTMS of the LFP (n = 12) and primary motor cortex (n = 12) in a high-craving, severe nicotine dependence population (9 females, 15 males). A cigarette cue-reactivity paradigm with smoking-related and neutral visual stimuli was used for primary outcome measures. Chronic craving, dependence severity, impulsivity and cognitive measures were also obtained.

RESULTS

Compared to baseline, LFP rTMS significantly reduced cue-reactivity to both smoking-related and neutral cue types, while no change occurred in the motor cortex group. Reactivity to affectively neutral pictures was significantly reduced in the LFP vs. motor cortex analysis. There was one robust correlation between verbal memory recall score and reduction of neutral cue-reactivity.

CONCLUSIONS

LFP 1 Hz rTMS significantly reduced cigarette cue-reactivity. Association of change in cue-reactivity with verbal memory performance suggests a relationship between craving experiences and declarative memory systems that seems relevant to rTMS effects.

A systematic review and meta-analysis of the efficacy of intermittent theta burst stimulation (iTBS) on cognitive enhancement

Intermittent theta-burst stimulation (iTBS) has been used to focally regulate excitability of neural cortex over the past decade - however there is little consensus on the generalizability of effects reported in individual studies. Many studies use small sample sizes (N < 30), and there is a considerable amount of methodological heterogeneity in application of the stimulation itself. This systematic meta-analysis aims to consolidate the extant literature and determine if up-regulatory theta-burst stimulation reliably enhances cognition through measurable behavior. Results show that iTBS - when compared to suitable control conditions - may enhance cognition when outlier studies are removed, but also that there is a significant amount of heterogeneity across studies. Significant contributors to between-study heterogeneity include location of stimulation and method of navigation to the stimulation site. Surprisingly, the type of cognitive domain investigated was not a significant contributor of heterogeneity. The findings of this meta-analysis demonstrate that standardization of iTBS is urgent and necessary to determine if neuroenhancement of particular cognitive faculties are reliable and robust, and measurable through observable behavior.

A double-blind study assessing the impact of orbitofrontal theta burst stimulation on goal-directed behavior

Patients with disorders of compulsivity show impairments in goal-directed behavior, which have been linked to orbitofrontal cortex (OFC) dysfunction. We recently showed that continuous theta burst stimulation (cTBS), which reduces OFC activity, had a beneficial effect on compulsive behaviors both immediately and at 1 week follow-up compared with inhibitory TBS (iTBS). In this same sample, we investigated whether two behavioral measures of goal-directed control (devaluation success on a habit override task; model-based planning on the two-step task) were also affected by acute modulation of OFC activity. Overall, model-based planning and devaluation success were significantly related to each other and (for devaluation success) to symptoms in our transdiagnostic clinical sample. These measures were moderately to highly stable across time. In individuals with low levels of model-based planning, active cTBS improved devaluation success. Analogous to previously reported clinical effects, this effect was specific to cTBS and not iTBS. Overall, results suggested that measures of goal directed behavior are reliable but less affected by cTBS than clinical self-report. Future research should continue to examine longitudinal changes in behavioral measures to determine their temporal relationship with symptom improvement after treatment. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Medial prefrontal cortex theta burst stimulation improves treatment outcomes in Alcohol Use Disorder: a double-blind, sham-controlled neuroimaging study

Background

Alcohol use disorder (AUD) is associated with elevated brain response to cues. Recent studies have suggested that theta burst stimulation (TBS) to the medial prefrontal cortex (MPFC) can decrease reactivity to cues in a transdiagnostic manner. The goal of this clinical trial was to evaluate the effect of continuous TBS as a tool to decrease drinking behavior and brain reactivity to alcohol cues among individuals with AUD.

Methods

A total of 50 individuals with AUD were recruited from an intensive outpatient treatment program. Using a randomized, double-blind, sham-controlled design, participants received 10 sessions of continuous TBS (left frontal pole, 1 session/10 days, 110% resting motor threshold, 3600 pulse/session, cue provocation before and during session). Brain reactivity to alcohol cues was acquired at four time points: at baseline and after all TBS sessions (1 month, 2 months, and 3 months).

Results

Overall, 80% of the participants completed all TBS sessions. Individuals who received real TBS were 2.71 times more likely to remain enrolled in the study after 3 months and 3.09 times more likely to remain sober 3 months after treatment initiation. Real TBS also led to a significantly greater reduction in brain reactivity to alcohol cues, specifically a reduction in MPFC-striatum and MPFC-insula connectivity 2 and 3 months after TBS treatment.

Conclusions

Ten days of MPFC TBS is well tolerated, reduces drinking, and decreases brain reactivity to alcohol cues for up to 3 months after treatment initiation. These results pave a critical next step in the path toward developing transcranial magnetic stimulation as an intervention for AUD and disorders associated with elevated cue reactivity.

Targeting the Salience Network: A Mini-Review on a Novel Neuromodulation Approach for Treating Alcohol Use Disorder

Alcohol use disorder (AUD) continues to be challenging to treat despite the best available interventions, with two-thirds of individuals going on to relapse by 1 year after treatment. Recent advances in the brain-based conceptual framework of addiction have allowed the field to pivot into a neuromodulation approach to intervention for these devastative disorders. Small trials of repetitive transcranial magnetic stimulation (rTMS) have used protocols developed for other psychiatric conditions and applied them to those with addiction with modest efficacy. Recent evidence suggests that a TMS approach focused on modulating the salience network (SN), a circuit at the crossroads of large-scale networks associated with AUD, may be a fruitful therapeutic strategy. The anterior insula or dorsal anterior cingulate cortex may be particularly effective stimulation sites given emerging evidence of their roles in processes associated with relapse.

Efficacy of neurostimulation across mental disorders: systematic review and meta-analysis of 208 randomized controlled trials

Non-invasive brain stimulation (NIBS), including transcranial magnetic stimulation (TMS), and transcranial direct current stimulation (tDCS), is a potentially effective treatment strategy for a number of mental conditions. However, no quantitative evidence synthesis of randomized controlled trials (RCTs) of TMS or tDCS using the same criteria including several mental conditions is available. Based on 208 RCTs identified in a systematic review, we conducted a series of random effects meta-analyses to assess the efficacy of NIBS, compared to sham, for core symptoms and cognitive functioning within a broad range of mental conditions. Outcomes included changes in core symptom severity and cognitive functioning from pre- to post-treatment. We found significant positive effects for several outcomes without significant heterogeneity including TMS for symptoms of generalized anxiety disorder (SMD = -1.8 (95% CI: -2.6 to -1), and tDCS for symptoms of substance use disorder (-0.73, -1.00 to -0.46). There was also significant effects for TMS in obsessive-compulsive disorder (-0.66, -0.91 to -0.41) and unipolar depression symptoms (-0.60, -0.78 to -0.42) but with significant heterogeneity. However, subgroup analyses based on stimulation site and number of treatment sessions revealed evidence of positive effects, without significant heterogeneity, for specific TMS stimulation protocols. For neurocognitive outcomes, there was only significant evidence, without significant heterogeneity, for tDCS for improving attention (-0.3, -0.55 to -0.05) and working memory (-0.38, -0.74 to -0.03) in individuals with schizophrenia. We concluded that TMS and tDCS can benefit individuals with a variety of mental conditions, significantly improving clinical dimensions, including cognitive deficits in schizophrenia which are poorly responsive to pharmacotherapy.

Concurrent TMS-fMRI: Technical Challenges, Developments, and Overview of Previous Studies

Transcranial magnetic stimulation (TMS) is a promising treatment modality for psychiatric and neurological disorders. Repetitive TMS (rTMS) is widely used for the treatment of psychiatric and neurological diseases, such as depression, motor stroke, and neuropathic pain. However, the underlying mechanisms of rTMS-mediated neuronal modulation are not fully understood. In this respect, concurrent or simultaneous TMS-fMRI, in which TMS is applied during functional magnetic resonance imaging (fMRI), is a viable tool to gain insights, as it enables an investigation of the immediate effects of TMS. Concurrent application of TMS during neuroimaging usually causes severe artifacts due to magnetic field inhomogeneities induced by TMS. However, by carefully interleaving the TMS pulses with MR signal acquisition in the way that these are far enough apart, we can avoid any image distortions. While the very first feasibility studies date back to the 1990s, recent developments in coil hardware and acquisition techniques have boosted the number of TMS-fMRI applications. As such, a concurrent application requires expertise in both TMS and MRI mechanisms and sequencing, and the hurdle of initial technical set up and maintenance remains high. This review gives a comprehensive overview of concurrent TMS-fMRI techniques by collecting (1) basic information, (2) technical challenges and developments, (3) an overview of findings reported so far using concurrent TMS-fMRI, and (4) current limitations and our suggestions for improvement. By sharing this review, we hope to attract the interest of researchers from various backgrounds and create an educational knowledge base.

Repetitive Transcranial Magnetic Stimulation for Comorbid Major Depressive Disorder and Alcohol Use Disorder

Major depressive disorder (MDD) and alcohol use disorder (AUD) are leading causes of disability, and patients are frequently affected by both conditions. This comorbidity is known to confer worse outcomes and greater illness severity. Repetitive transcranial magnetic stimulation (rTMS) is a non-invasive neuromodulation method that has demonstrated antidepressant effects. However, the study of rTMS for patients with MDD and commonly associated comorbidities, such as AUD, has been largely overlooked, despite significant overlap in clinical presentation and neurobiological mechanisms. This narrative review aims to highlight the interrelated aspects of the literature on rTMS for MDD and rTMS for AUD. First, we summarize the available evidence on the effectiveness of rTMS for each condition, both most studied through stimulation of the dorsolateral prefrontal cortex (DLPFC). Second, we describe common symptom constructs that can be modulated by rTMS, such as executive dysfunction, that are transdiagnostic across these disorders. Lastly, we describe promising approaches in the personalization and optimization of rTMS that may be applicable to both AUD and MDD. By bridging the gap between research efforts in MDD and AUD, rTMS is well positioned to be developed as a treatment for the many patients who have both conditions concurrently.

Using diffusion tensor imaging to effectively target TMS to deep brain structures

TMS has become a powerful tool to explore cortical function, and in parallel has proven promising in the development of therapies for various psychiatric and neurological disorders. Unfortunately, much of the inference of the direct effects of TMS has been assumed to be limited to the area a few centimeters beneath the scalp, though clearly more distant regions are likely to be influenced by structurally connected stimulation sites. In this study, we sought to develop a novel paradigm to individualize TMS coil placement to non-invasively achieve activation of specific deep brain targets of relevance to the treatment of psychiatric disorders. In ten subjects, structural diffusion imaging tractography data were used to identify an accessible cortical target in the right frontal pole that demonstrated both anatomic and functional connectivity to right Brodmann area 25 (BA25). Concurrent TMS-fMRI interleaving was used with a series of single, interleaved TMS pulses applied to the right frontal pole at four intensity levels ranging from 80% to 140% of motor threshold. In nine of ten subjects, TMS to the individualized frontal pole sites resulted in significant linear increase in BOLD activation of BA25 with increasing TMS intensity. The reliable activation of BA25 in a dosage-dependent manner suggests the possibility that the careful combination of imaging with TMS can make use of network properties to help overcome depth limitations and allow noninvasive brain stimulation to influence deep brain structures.

Neurobiological mechanisms of control in alcohol use disorder - moving towards mechanism-based non-invasive brain stimulation treatments

Alcohol use disorder (AUD) is characterized by excessive habitual drinking and loss of control over alcohol intake despite negative consequences. Both of these aspects foster uncontrolled drinking and high relapse rates in AUD patients. Yet, common interventions mostly focus on the phenomenological level, and prioritize the reduction of craving and withdrawal symptoms. Our review provides a mechanistic understanding of AUD and suggests alternative therapeutic approaches targeting the mechanisms underlying dysfunctional alcohol-related behaviours. Specifically, we explain how repeated drinking fosters the development of rigid drinking habits and is associated with diminished cognitive control. These behavioural and cognitive effects are then functionally related to the neurobiochemical effects of alcohol abuse. We further explain how alterations in fronto-striatal network activity may constitute the neurobiological correlates of these alcohol-related dysfunctions. Finally, we discuss limitations in current pharmacological AUD therapies and suggest non-invasive brain stimulation (like TMS and tDCS interventions) as a potential addition/alternative for modulating the activation of both cortical and subcortical areas to help re-establish the functional balance between controlled and automatic behaviour.

Noninvasive brain stimulation of addiction: one target for all?

Noninvasive brain stimulation includes repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS), and emerges as a prospective approach for addiction treatment in clinical practices. The dorsolateral prefrontal cortex (DLPFC) is regarded as the most effective stimulation target, giving its important position in controlling cue-elicited drug craving and initiating drug abuse. In this paper, through literature searches (e.g. Pubmed, Google Scholar), 34 studies (2003-2021) were identified examining the effect of rTMS, tDCS on cravings, and consumption of substance use disorders, including tobacco, alcohol, opioids, and stimulants. We summarize the main methods, designs, and effects of rTMS or tDCS that are delivered to the DLPFC on different types of addiction. We conclude that targeting DLPFC might be effective for all types of drug addiction.

Transcranial Magnetic Stimulation for the Treatment of Cocaine Addiction: A Systematic Review

Long-term cocaine use is associated with cognitive deficits and neuro-psychiatric pathologies. Repetitive transcranial magnetic stimulation (rTMS) is an emerging therapeutic strategy relating to changes in brain activity. It stimulates the prefrontal cortex and is involved in inhibitory cognitive control, decision making and care. This systematic review aims to evaluate and synthesize the evidence on the safety, effectiveness, and cost-effectiveness of rTMS for the treatment of cocaine addiction. A systematic review of the literature was carried out. The following electronic databases were consulted from inception to October 2020: MEDLINE, Embase, CINAHL, PsycINFO, Cochrane Central Register of Controlled Trials and Web of Science. Randomised controlled trials, non-randomised controlled trials and case-series and full economic evaluations were included. Twelve studies were included. No identified study reported data on cost-effectiveness. Significant results of the efficacy of TMS have been observed in terms of the reduction of craving to consume and the number of doses consumed. No serious adverse effects have been observed. Despite the low quality of the studies, the first results were observed in terms of reduction of cocaine use and craving. In any case, this effect is considered moderate. Studies with larger sample sizes and longer follow-ups are required.

A randomised, double-blind, sham-controlled study of left prefrontal cortex 15 Hz repetitive transcranial magnetic stimulation in cocaine consumption and craving

Background

Cocaine use disorder (CUD) is a global health issue with no effective treatment. Repetitive Transcranial Magnetic Stimulation (rTMS) is a recently proposed therapy for CUD.

Methods

We conducted a single-center, randomised, sham-controlled, blinded, parallel-group research with patients randomly allocated to rTMS (15 Hz) or Sham group (1:1) using a computerised block randomisation process. We enrolled 62 of 81 CUD patients in two years. Patients were followed for eight weeks after receiving 15 15 Hz rTMS/sham sessions over the left dorsolateral prefrontal cortex (DLPFC) during the first three weeks of the study. We targeted the DLFPC following the 5 cm method. Cocaine lapses in twice a week urine tests were the primary outcome. The secondary outcomes were craving severity, cocaine use pattern, and psychometric assessments.

Findings

We randomly allocated patients to either an active rTMS group (32 subjects) or a sham treatment group (30 subjects). Thirteen (42%) and twelve (43.3%) of the subjects in rTMS and sham groups, respectively, completed the full trial regimen, displaying a high dropout rate. Ten/30 (33%) of rTMS-treated patients tested negative for cocaine in urine, in contrast to 4/27 of placebo controls (p = 0.18, odd ratio 2.88, CI 0.9–10). The Kaplan-Meier survival curve did not state a significant change between the treated and sham groups in the time of cocaine urine negativisation (p = 0.20). However, the severity of cocaine-related cues mediated craving (VAS peak) was substantially decreased in the rTMS treated group (p<0.03) after treatment at T1, corresponding to the end of rTMS treatment. Furthermore, in the rTMS and sham groups, self-reported days of cocaine use decreased significantly (p<0.03). Finally, psychometric impulsivity parameters improved in rTMS-treated patients, while depression scales improved in both groups.

Conclusions

In CUD, rTMS could be a useful tool for lowering cocaine craving and consumption.

Trial registration

The study number on clinicalTrials.gov is NCT03607591.

Personalization of Repetitive Transcranial Magnetic Stimulation for the Treatment of Major Depressive Disorder According to the Existing Psychiatric Comorbidity

Repetitive transcranial magnetic stimulation (rTMS) and intermittent theta-burst stimulation (iTBS) are evidenced-based treatments for patients with major depressive disorder (MDD) who fail to respond to standard first-line therapies. However, although various TMS protocols have been proven to be clinically effective, the response rate varies across clinical applications due to the heterogeneity of real-world psychiatric comorbidities, such as generalized anxiety disorder, posttraumatic stress disorder, panic disorder, or substance use disorder, which are often observed in patients with MDD. Therefore, individualized treatment approaches are important to increase treatment response by assigning a given patient to the most optimal TMS treatment protocol based on his or her individual profile. This literature review summarizes different rTMS or TBS protocols that have been applied in researches investigating MDD patients with certain psychiatric comorbidities and discusses biomarkers that may be used to predict rTMS treatment response. Furthermore, we highlight the need for the validation of neuroimaging and electrophysiological biomarkers associated with rTMS treatment responses. Finally, we discuss on which directions future efforts should focus for developing the personalization of the treatment of depression with rTMS or iTBS.

Effect of Experimental Manipulation of the Orbitofrontal Cortex on Short-Term Markers of Compulsive Behavior: A Theta Burst Stimulation Study

OBJECTIVE

Compulsive behaviors are a core feature of obsessive-compulsive spectrum disorders but appear across a broad spectrum of psychological conditions. It is thought that compulsions reflect a failure to override habitual behaviors "stamped in" through repeated practice and short-term distress reduction. Animal models suggest a possible causal role of the orbitofrontal cortex (OFC) in compulsive behaviors, but human studies have largely been limited by correlational designs. The goal of this study was to establish the first experimental evidence in humans for a mechanistic model in order to inform further experimental work and the eventual development of novel mechanistic treatments involving synergistic biological-behavioral pairings.

METHODS

After a baseline assessment, 69 individuals with compulsive behavior disorders were randomly assigned, in a double-blind, between-subjects design, to receive a single session of one of two active stimulation conditions targeting the left OFC: intermittent theta burst stimulation (iTBS), expected to increase OFC activity, or continuous TBS (cTBS), expected to decrease activity (both conditions, 600 pulses at 110% of target resting motor threshold). In both conditions, brain modulation was paired with a subsequent computer task providing practice in overriding a clinically relevant habit (an overlearned shock avoidance behavior), delivered during the expected window of OFC increase or decrease. Pre- and post-TBS functional MRI assessments were conducted of target engagement and compulsive behaviors performed in response to an idiographically designed stressful laboratory probe.

RESULTS

cTBS and iTBS modulated OFC activation in the expected directions. cTBS, relative to iTBS, exhibited a beneficial impact on acute laboratory assessments of compulsive behaviors 90 minutes after TBS. These acute behavioral effects persisted 1 week after cTBS.

CONCLUSIONS

Experimental modulation of the OFC, within the behavioral context of habit override training, affected short-term markers of compulsive behavior vulnerability. The findings help delineate a causal translational model, serving as an initial precursor to mechanistic intervention development.

Concurrent TMS-fMRI for causal network perturbation and proof of target engagement

The experimental manipulation of neural activity by neurostimulation techniques overcomes the inherent limitations of correlative recordings, enabling the researcher to investigate causal brain-behavior relationships. But only when stimulation and recordings are combined, the direct impact of the stimulation on neural activity can be evaluated. In humans, this can be achieved non-invasively through the concurrent combination of transcranial magnetic stimulation (TMS) with functional magnetic resonance imaging (fMRI). Concurrent TMS-fMRI allows the assessment of the neurovascular responses evoked by TMS with excellent spatial resolution and full-brain coverage. This enables the functional mapping of both local and remote network effects of TMS in cortical as well as deep subcortical structures, offering unique opportunities for basic research and clinical applications. The purpose of this review is to introduce the reader to this powerful tool. We will introduce the technical challenges and state-of-the art solutions and provide a comprehensive overview of the existing literature and the available experimental approaches. We will highlight the unique insights that can be gained from concurrent TMS-fMRI, including the state-dependent assessment of neural responsiveness and inter-regional effective connectivity, the demonstration of functional target engagement, and the systematic evaluation of stimulation parameters. We will also discuss how concurrent TMS-fMRI during a behavioral task can help to link behavioral TMS effects to changes in neural network activity and to identify peripheral co-stimulation confounds. Finally, we will review the use of concurrent TMS-fMRI for developing TMS treatments of psychiatric and neurological disorders and suggest future improvements for further advancing the application of concurrent TMS-fMRI.

Determining the optimal pulse number for theta burst induced change in cortical excitability

Theta-burst stimulation (TBS) is a form of non-invasive neuromodulation which is delivered in an intermittent (iTBS) or continuous (cTBS) manner. Although 600 pulses is the most common dose, the goal of these experiments was to evaluate the effect of higher per-dose pulse numbers on cortical excitability. Sixty individuals were recruited for 2 experiments. In Experiment 1, participants received 600, 1200, 1800, or sham (600) iTBS (4 visits, counterbalanced, left motor cortex, 80% active threshold). In Experiment 2, participants received 600, 1200, 1800, 3600, or sham (600) cTBS (5 visits, counterbalanced). Motor evoked potentials (MEP) were measured in 10-min increments for 60 min. For iTBS, there was a significant interaction between dose and time (F = 3.8296, p = 0.01), driven by iTBS (1200) which decreased excitability for up to 50 min (t = 3.1267, p = 0.001). For cTBS, there was no overall interaction between dose and time (F = 1.1513, p = 0.33). Relative to sham, cTBS (3600) increased excitability for up to 60 min (t = 2.0880, p = 0.04). There were no other significant effects of dose relative to sham in either experiment. Secondary analyses revealed high within and between subject variability. These results suggest that iTBS (1200) and cTBS (3600) are, respectively, the most effective doses for decreasing and increasing cortical excitability.

Repetitive Transcranial Magnetic Stimulation as a Therapeutic and Probe in Schizophrenia: Examining the Role of Neuroimaging and Future Directions

Schizophrenia is a complex condition associated with perceptual disturbances, decreased motivation and affect, and disrupted cognition. Individuals living with schizophrenia may experience myriad poor outcomes, including impairment in independent living and function as well as decreased life expectancy. Though existing treatments may offer benefit, many individuals still experience treatment resistant and disabling symptoms. In light of the negative outcomes associated with schizophrenia and the limitations in currently available treatments, there is a significant need for novel therapeutic interventions. Repetitive transcranial magnetic stimulation (rTMS) is a non-invasive brain stimulation technique that can modulate the activity of discrete cortical regions, allowing direct manipulation of local brain activation and indirect manipulation of the target's associated neural networks. rTMS has been studied in schizophrenia for the treatment of auditory hallucinations, negative symptoms, and cognitive deficits, with mixed results. The field's inability to arrive at a consensus on the use rTMS in schizophrenia has stemmed from a variety of issues, perhaps most notably the significant heterogeneity amongst existing trials. In addition, it is likely that factors specific to schizophrenia, rather than the rTMS itself, have presented barriers to the interpretation of existing results. However, advances in approaches to rTMS as a biologic probe and therapeutic, many of which include the integration of neuroimaging with rTMS, offer hope that this technology may still play a role in improving the understanding and treatment of schizophrenia.

Efficacy of intensive orbitofrontal continuous Theta Burst Stimulation (iOFcTBS) in Obsessive Compulsive Disorder: A Randomized Placebo Controlled Study

Transcranial magnetic stimulation (TMS) can non-invasively modulate specific brain regions in Obsessive-compulsive disorder (OCD). Citing orbito-frontal cortex (OFC) hyper-connectivity with striatum as the most consistent finding implicated in patho-physiologically of OCD, we aimed to study the effect of novel continuous Theta Burst Stimulation (cTBS) targeting OFC in OCD subjects on a randomized placebo control design. Thirty-three patients were randomly allocated to active cTBS (n= 18) and sham (n= 15) groups. They received 10 TBS sessions, 2 per day (total of 1200 pulses; intensive protocol) for 5 days in a week. The Yale Brown Obsessive Compulsive Scale (Y-BOCS), Hamilton Depression Rating Scale (HAM-D), Hamilton Anxiety Rating Scale (HAM-A), and Clinical Global Impression-Severity (CGI-S) scores were assessed at baseline, after last session and at 2 weeks post-rTMS. On repeated measures-ANOVA, a significant group*time effect (from pretreatment to 2 weeks post TBS) for obsessions, compulsions, HAM-A, HAM-D, and CGI scores was found. But when controlled for confounding variables, only HAM-A scores and CGI effect retained statistical significance. We conclude that intensive OFC cTBS (iOFcTBS) in OCD is well tolerated with clinically significant improvements in anxiety symptoms and global severity. This improvement in anxiety symptoms could be due to modulations of state dependent dysregulation in OCD.

Causal investigations into orbitofrontal control of human decision making

Although it is widely accepted that the orbitofrontal cortex (OFC) is important for decision making, its precise contribution to behavior remains a topic of debate. While many loss of function experiments have been conducted in animals, causal studies of human OFC function are relatively scarce. This review discusses recent causal investigations into the human OFC, with an emphasis on advances in network-based brain stimulation approaches to indirectly perturb OFC function. Findings show that disruption of human OFC impairs decisions that require mental simulation of outcomes. Taken together, these results support the idea that human OFC contributes to decision making by representing a cognitive map of the task environment, facilitating inference of outcomes not yet experienced. Future work may utilize similar non-invasive approaches in clinical settings to mitigate decision making deficits in neuropsychiatric disorders.

Transcranial magnetic stimulation and neuroimaging for cocaine use disorder: Review and future directions

Background: Cocaine use disorder (CUD) is a public health problem with limited treatment options and a significant relapse rate. Neuroimaging studies have identified abnormal functional connectivity in individuals with substance use disorders. Neuromodulation has been proposed to target this altered neurocircuitry. Combining TMS with neuroimaging has the potential to inform identification of biomarkers, diagnosis, and treatment.Objectives: We review the literature of transcranial magnetic stimulation (TMS) with neuroimaging for CUD and outline a research path forward whereby TMS can be used to identify brain network features as diagnostic or prognostic biomarkers for treatment.Methods: We reviewed the literature for primary research studies of TMS with neuroimaging for CUD. We searched PubMed using search terms of "cocaine," "transcranial magnetic stimulation," and "neuroimaging." Identified studies were screened by title and abstract. Full-text studies were reviewed for inclusion.Results: In our initial search, we identified 73 studies. Six studies met our inclusion criteria. These studies used rTMS (n = 3) and single or paired pulse TMS (n = 3) and included a total of 289 participants. All studies used fMRI as the neuroimaging modality. The most common outcome measure was craving and cue-reactivity (n = 3).Conclusion: The literature combining TMS with neuroimaging is small and heterogeneous. We propose that combining TMS with neuroimaging will accelerate our understanding of substance use disorder neurobiology and treatment. Once network biomarkers of substance use have been identified, TMS can be used to manipulate the dysfunctional circuits in order to identify a causal relationship between connectivity and psychopathology.