rTMS Therapy Reduces Hypofrontality in Patients With Depression as Measured by fNIRS

Sex differences in behavior, cognitive, and physiological recovery following methamphetamine administration

Intact executive functions are required for proper performance of cognitive tasks and relies on balance of excitatory and inhibitory (E/I) transmission in the medial prefrontal cortex (mPFC). Hypofrontality is a state of decreased activity in the mPFC and is seen in several neuropsychiatric conditions, including substance use disorders. People who chronically use methamphetamine (meth) develop hypofrontality and concurrent changes in cognitive processing across several domains. Despite the fact that there are sex difference in substance use disorders, few studies have considered sex as a biological variable regarding meth-mediated hypoactivity in mPFC and concurrent cognitive deficits. Hypofrontality along with changes in cognition are emulated in rodent models following repeated meth administration. Here, we used a meth sensitization regimen to study sex differences in a Temporal Order Memory (TOM) task following short (7 days) or prolonged (28 days) periods of abstinence. GABAergic transmission, GABAA receptor (GABAAR) and GABA Transporter (GAT) mRNA expression in the mPFC were evaluated with patch-clamp recordings and RT-qPCR, respectively. Both sexes sensitized to the locomotor activating effects of meth, with the effect persisting in females. After short abstinence, males and females had impaired TOM and increased GABAergic transmission. Female rats recovered from these changes after prolonged abstinence, whereas male rats showed enduring changes. In general, meth appears to elicit an overall decrease in GABAAR expression after short abstinence; whereas GABA transporters are decreased in meth female rats after prolonged abstinence. These results show sex differences in the long-term effects of repeated meth exposure and suggest that females have neuroprotective mechanisms that alleviate some of the meth-mediated cognitive deficits.

rTMS for post-covid-19 condition: A sham-controlled case series involving iTBS-300 and iTBS-600

Post-Covid-19 Condition (PCC) is a syndrome comprised of symptoms persisting 3 months or more beyond SARS-CoV-2 primary infection. It is typically characterized by fatigue, cognitive problems and psychiatric symptoms, as well as cardiac symptoms that contribute to exercise intolerance in many. Despite the high prevalence of PCC among those with a prior SARS-CoV-2 infection, there is currently no widely accepted rehabilitation strategy, and many conventional modalities are movement-based. Non-invasive brain stimulation methods such as repetitive transcranial magnetic stimulation (rTMS) may have some potential to alleviate the cognitive and affective symptoms of PCC without reliance on exercise. The purpose of the present study was to explore the feasibility and tolerability of using rTMS to treat symptoms of "brain fog" and affective disturbance among those living with PCC, using a case series design. We enrolled four individuals with PCC following a confirmed SARS-CoV-2 infection, at least 3 months after the resolution of the primary infection. Participants were randomized to 4 sessions of active and 2 sessions of sham intermittent theta-burst stimulation (iTBS); two intensities of iTBS were evaluated: iTBS-300 and iTBS-600. No adverse events occurred in active or sham stimulation; 2 participants reported tingling sensation on the scalp but no other tolerability issues. Trends in symptoms suggested improvements in cognitive interference, quality of life, and anxiety in the majority of participants. In summary, in this case series iTBS was well tolerated among 4 individuals with PCC; active stimulation was associated with positive trends in some primary symptom clusters as compared with sham stimulation. Future studies should examine the effects of iTBS on PCC symptoms in the context of experimental studies and randomized controlled trials.

Using functional near-infrared spectroscopy to study effects of virtual reality intervention for adolescents with depression in a clinical setting in China: study protocol for a prospective, randomised, controlled trial

INTRODUCTION

Adolescent depression has been shown to be associated with many devastating psychosocial outcomes. However, there are many barriers that may prevent depressed individuals from receiving specialised treatment. Virtual reality (VR) technology has shown promise as one avenue for overcoming these challenges. This study first aims to evaluate the effectiveness of VR intervention on adolescent depression symptoms, and second, to determine the intervention's underlying mechanism of effect using functional near-infrared spectroscopy (fNIRS).

METHODS AND ANALYSIS

This is a single-centre, prospective, randomised controlled clinical trial. Sixty-six eligible adolescents aged 12-18 years with a diagnosis of depression will be randomised in a 1:1 ratio to either the VR treatment group or the conventional treatment group. All patients for both groups will receive usual treatment during a 4-week intervention period. In addition, patients randomised to VR treatment group (n=33) will complete three 20 min VR sessions including attention, executive function and relaxation training per week. Moreover, 33 healthy adolescents will be recruited as the general population. Primary outcome (ie, depressive symptoms) and secondary outcomes (ie, anxiety symptoms, executive function, treatment emergent symptoms, haemoglobin changes measured by fNIRS) will be collected at preintervention, immediately postintervention and at 4 weeks follow-up. The data assessor and analyst will be blinded to group membership.

ETHICS AND DISSEMINATION

Ethical approval has been obtained from the Ethics Committee of Lishui Second People's Hospital. Written informed consent will be obtained for all participants. Results will be disseminated through peer-reviewed journals, national or international conference presentations, media outlets, the internet and various community activities.

TRIAL REGISTRATION NUMBER

ChiCTR2300067747.

Associations between frontal lobe activity and depressive symptoms in patients with major depressive disorder receiving rTMS treatment: a near-infrared spectroscopy study

Introduction

The effects of repetitive transcranial magnetic stimulation (rTMS) on the left dorsolateral prefrontal cortex (DLPFC) in patients with major depressive disorder (MDD) have been proved to have antidepressant effects. However, the absence of biomarkers to assess treatment response remains a challenge. This research aims to explore the relationship between frontal lobe activity, measured using near infrared spectroscopy (NIRS), and changes in symptoms among MDD patients following rTMS treatment.

Methods

A total of 26 MDD patients underwent 20 sessions of 10  Hz rTMS targeting the left DLPFC. NIRS was used to measure frontal lobe activity during a verbal fluency test at baseline, after 10 rTMS sessions, and after 20 rTMS sessions. Responders were defined as individuals with more than a 50% reduction in symptoms based on the 21-item Hamilton Depression Rating Scale after 20 rTMS sessions.

Results

Among the 14 responders, an increase in frontal lobe activity was significantly correlated with improvements in depressive symptoms following 10 (p = 0.0001) and 20 rTMS sessions (p = 0.007). Additionally, frontal lobe activity after 10 rTMS sessions was significantly associated with symptom improvement after 20 sessions (p = 0.001). These associations were not observed among non-responders.

Conclusion

The findings from this study indicate distinct patterns of frontal lobe activity between responders and non-responders to rTMS treatment, suggesting that NIRS has the potential to serve as a biomarker for monitoring treatment response in MDD patients undergoing rTMS.

Transcranial Magnetic Stimulation (TMS) for Major Depressive Disorder-Modus Operandi!

Background

Transcranial magnetic stimulation (TMS) is effective in the management of treatment resistant major depressive disorder (MDD) and has recently become widely available. Our aim was to explore the literature for evidence of the mechanism of action.

Method

We examined our own accumulating TMS library, the reference lists of all available papers and used a search engine to collect information. We collated and examined this information under relevant heading.

Results

TMS produces a large number of physiological changes including site of stimulation neurochemical, brain wave and blood flow effects, and distant structure effects including neurotransmitter effects and volume increase. TMS also corrects generalized and local functional connectivity (FC) abnormalities which are a feature of MDD.

Conclusion

TMS produces a range of physiological changes. It is unclear which of these underpin its antidepressant. It is likely more than one work synergistically to this end-almost certainly the capacity to correct MDD induced FC abnormalities makes a strong antidepressant contribution.

Exploring fNIRS-Based Brain State Recognition and Visualization through the use of Explainable Convolutional Neural Networks

Functional near infrared spectroscopy (fNIRS) is a neuroimaging technique that has grown vigorously in recent years. With noticeable attention, machine learning methods have also been applied to fNIRS. However, the current approach lacks interpretability of the results. In recent years, the utilization and investigation of fNIRS have experienced significant growth and are now being utilized in clinical research. However, the collection of clinical fNIRS data is limited in sample size. Therefore, our aim is to utilize the collected fNIRS data from all channels and achieve interpretable analysis results with minimal human manipulation, channel selection or feature extraction. We developed an fNIRS-based interpretable model and used class-specific gradient information to visualize the biomarkers captured by the model via locating the important region. The accuracy of our model's classification was 6% higher than that of the conventional SVM method under within-subject classification. The model focuses on signals from the left brain in the classification of right-hand finger tapping task, while in the task of classifying left-handed movements, the model relies on signals from the right brain. These results were consistent with current understanding of physiology.Clinical Relevance- The machine learning-based fNIRS model has the potential to be used for the diagnosis and prediction of therapeutic efficacy in clinical settings.

Insomniacs show greater prefrontal activation during verbal fluency task compared to non-insomniacs: a functional near-infrared spectroscopy investigation of depression in patients

BACKGROUND

Previous studies have shown that insomnia affects human prefrontal function and that there are specific patterns of brain activation to counteract sleep and improve cognition. However, the effects of insomnia on the prefrontal cortex of MDD (major depressive disorder) patients and the patterns of activation to counteract sleep in MDD patients remain unclear. The aim of this study is to examine this using fNIRS (functional near-infrared spectroscopy).

METHODS

Eighty depressed patients and 44 healthy controls were recruited for this study. fNIRS was used to assess changes in the concentration of oxygenated hemoglobin ([oxy-Hb]) in the prefrontal cortex of all participants during the VFT (verbal fluency test) and to record the number of words created to assess cognitive ability. The Pittsburgh Sleep Quality Index was used to assess sleep quality, and the Hamilton Rating Scale for Depression (24-item) and Hamilton Rating Scale for Anxiety (14-item) were used to assess the severity of depression and anxiety.

RESULTS

When comparing patients, the healthy control group had significantly higher [oxy-Hb] values in the bilateral prefrontal cortex during VFT than the MDD group. In the MDD group, the [oxy-Hb] values in all brain regions except the right DLPFC were significantly higher in the group with insomnia than in the group without insomnia, but their VFT performance was significantly lower than in the group without insomnia and the healthy group. PSQI scores were positively correlated with [oxy-Hb] values in some left-brain regions, whereas HAMD and HAMA scores were not correlated with [oxy-Hb] values.

CONCLUSION

The PFC was significantly less active during VFT in those with MDD than in healthy controls. All brain regions, except the right DLPFC, were significantly more active in MDD patients with insomnia than in those without insomnia, suggesting that sleep quality needs to be an important indicator in fNIRS screening. In addition, there was a positive correlation between the severity of insomnia in the left VLPFC and the level of activation, suggesting a role for the left brain region in the neurophysiology of overcoming sleepiness in MDD patients. these findings may provide new ideas for the treatment of MDD patients in the future.

TRIAL REGISTRATION

Our experiment was registered in the China Clinical Trial Registry (registration number ChiCTR2200065622) on November 10.( The first patient was recruited in 10/11/2022.).