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NeuroImage. Clinical 2024Changes in eating behaviour including reductions in appetite and food intake, and healthier food cue reactivity, reward, hedonics and potentially also preference,... (Review)
Review
Changes in eating behaviour including reductions in appetite and food intake, and healthier food cue reactivity, reward, hedonics and potentially also preference, contribute to weight loss and its health benefits after obesity surgery. Functional magnetic resonance imaging (fMRI) has been increasingly used to interrogate the neural correlates of eating behaviour in obesity, including brain reward-cognitive systems, changes after obesity surgery, and links with alterations in the gut-hormone-brain axis. Neural responses to food cues can be measured by changes in blood oxygen level dependent (BOLD) signal in brain regions involved in reward processing, including caudate, putamen, nucleus accumbens, insula, amygdala, orbitofrontal cortex, and top-down inhibitory control, including dorsolateral prefrontal cortex (dlPFC). This systematic review aimed to examine: (i) results of human fMRI studies involving obesity surgery, (ii) important methodological differences in study design across studies, and (iii) correlations and associations of fMRI findings with clinical outcomes, other eating behaviour measures and mechanistic measures. Of 741 articles identified, 23 were eligible for inclusion: 16 (69.6%) longitudinal, two (8.7%) predictive, and five (21.7%) cross-sectional studies. Seventeen studies (77.3%) included patients having Roux-en-Y gastric bypass (RYGB) surgery, six (26.1%) vertical sleeve gastrectomy (VSG), and five (21.7%) laparoscopic adjustable gastric banding (LAGB). The majority of studies (86.0%) were identified as having a very low risk of bias, though only six (27.3%) were controlled interventional studies, with none including randomisation to surgical and control interventions. The remaining studies (14.0%) had a low risk of bias driven by their control groups not having an active treatment. After RYGB surgery, food cue reactivity often decreased or was unchanged in brain reward systems, and there were inconsistent findings as to whether reductions in food cue reactivity was greater for high-energy than low-energy foods. There was minimal evidence from studies of VSG and LAGB surgeries for changes in food cue reactivity in brain reward systems, though effects of VSG surgery on food cue reactivity in the dlPFC were more consistently found. There was consistent evidence for post-operative increases in satiety gut hormones glucagon-like-peptide 1 (GLP-1) and peptide YY (PYY) mediating reduced food cue reactivity after RYGB surgery, including two interventional studies. Methodological heterogeneity across studies, including nutritional state, nature of food cues, post-operative timing, lack of control groups for order effects and weight loss or dietary/psychological advice, and often small sample sizes, limited the conclusions that could be drawn, especially for correlational analyses with clinical outcomes, other eating behaviour measures and potential mediators. This systematic review provides a detailed data resource for those performing or analysing fMRI studies of obesity surgery and makes suggestions to help improve reporting and design of such studies, as well as future directions.
Topics: Humans; Cross-Sectional Studies; Obesity; Feeding Behavior; Magnetic Resonance Imaging; Weight Loss
PubMed: 38237270
DOI: 10.1016/j.nicl.2024.103563 -
Journal of Integrative Neuroscience Nov 2023Gambling Disorder (GD) is a behavioral addiction listed within the diagnostic category of substance-related and addictive disorders. Recently, transcranial magnetic...
BACKGROUND
Gambling Disorder (GD) is a behavioral addiction listed within the diagnostic category of substance-related and addictive disorders. Recently, transcranial magnetic stimulation (TMS), which non-invasively stimulates the brain and has neuromodulatory properties, has emerged as an innovative treatment tool for GD, thus offering a new option for the management of this complex disorder. The present review explored the efficacy of TMS as a possible non-pharmacological treatment for GD.
METHODS
An exhaustive search was performed across the MEDLINE, Web of Science, and EMBASE databases using a specific search string related to GD and TMS. A total of 20 papers were selected for full-text examination, out of which eight fulfilled the inclusion criteria and were therefore systematically analyzed in the present review.
RESULTS
This review included eight studies: three randomized-controlled trials (RCTs), three non-controlled studies, one case series, and one case report. Two cross-over RCTs described a decrease in craving after high-frequency (excitatory), repetitive transcranial magnetic stimulation (rTMS) over the left dorsolateral prefrontal cortex (DLPFC) and the medial prefrontal cortex (PFC), respectively; another study applying low-frequency (inhibitory) rTMS on the right DLPFC did not find any positive effect on craving. Among uncontrolled studies, one demonstrated the beneficial effect of high-frequency rTMS over the left DLPFC, while another showed the efficacy of a continuous theta burst stimulation protocol directed over the pre-supplementary motor area, bilaterally.
CONCLUSION
The included studies showed the promising effect of excitatory stimulation over the left PFC. However, further investigation is needed, particularly in terms of standardizing stimulation protocols and psychometric assessments.
Topics: Humans; Transcranial Magnetic Stimulation; Gambling; Craving; Prefrontal Cortex; Dorsolateral Prefrontal Cortex; Treatment Outcome
PubMed: 38176943
DOI: 10.31083/j.jin2206164 -
Journal of Integrative Neuroscience Nov 2023Premonitory urge (PU) is an aversive bodily sensation that signals the onset of tic disorder.To our knowledge, PU typically precedes the appearance of tic symptoms, and... (Meta-Analysis)
Meta-Analysis
INTRODUCTION
Premonitory urge (PU) is an aversive bodily sensation that signals the onset of tic disorder.To our knowledge, PU typically precedes the appearance of tic symptoms, and both age and tic severity are correlated with PU. However, inconsistent findings have also been reported. Hence, we conducted a meta-analysis to examine the relationship among premonitory symptoms, patient age and the severity of tic symptoms, as well as to summarize the research on the neural underpinnings of PU in Tourette syndrome (TS).
METHODS
We conducted a literature search of relevant studies published between December 2005 and April 2022 using databases such as PubMed, Elsevier, PsycINFO, and Web of Science. Our analysis was carried out using R software with the assistance of the "meta" and "metafor" packages.
RESULTS
Our meta-analysis included 22 studies with a total of 1236 tic disorder patients. The mean Premonitory Urge for Tics Scale (PUTS) score was 20.17, with a 95% confidence interval of [18.14, 21.68]. Through meta-regression, we found that age and tic severity play important moderating roles in PU severity ( < 0.0001). Neuroimaging studies suggest that PU is related to the insula, prefrontal cortex (PFC), anterior cingulate cortex (ACC), and supplementary motor area (SMA), regardless of the structural or functional level.
CONCLUSIONS
Our meta-analysis confirmed the positive relationship between the severity of tics and PU and identified age as a significant factor influencing PU. The neural mechanisms underlying PU remain largely unknown, but evidence suggests that the insula, PFC, ACC, and SMA are related regions.
Topics: Humans; Gyrus Cinguli; Neuroimaging; Tic Disorders; Tics; Tourette Syndrome
PubMed: 38176915
DOI: 10.31083/j.jin2206159 -
Folia Neuropathologica Jan 2024The role of functional magnetic resonance imaging (fMRI) findings in investigation of working memory (WM) deficit in schizophrenia patients is still debatable. The aim...
INTRODUCTION
The role of functional magnetic resonance imaging (fMRI) findings in investigation of working memory (WM) deficit in schizophrenia patients is still debatable. The aim of the study was to investigate the role of fMRI findings of the frontal and parietal brain activity in investigation of WM deficit in schizophrenia patients.
MATERIAL AND METHODS
We used Medline, Embase, and the Cochrane Database to conduct a comprehensive search up to January 2023. Functional MRI findings of schizophrenia patients were compared with healthy patients in comparative studies for assessing their WM capacity in terms of dorsolateral prefrontal cortex and parietal region activation. The Cochrane Risk of Bias Assessment Tool was used to evaluate the research quality.
RESULTS
Ten trials and 676 schizophrenia patients were included in our analysis. For the comparative assessment of primary outcome - alteration in dorsolateral prefrontal cortex and parietal region activity in schizophrenic patients versus healthy controls - we found the pooled odds ratio (OR) of 1.58 [95% CI: 1.09-2.29], I 2 = 61% and p = 0.01 and risk ratio (RR) was 1.27 [95% CI: 1.06-1.53], I 2 = 55% and p = 0.01. The AUC value of 0.944 indicates a favourable overall diagnostic performance of fMRI for the diagnosis of schizophrenia.
CONCLUSIONS
fMRI findings showing abnormalities in the parietal and frontal regions can be used to study schizophrenia patients' WM deficits.
PubMed: 38174682
DOI: 10.5114/fn.2023.132329 -
Journal of Psychiatric Research Feb 2024Based on existing evidence of the effects of the most commonly used non-invasive brain stimulation (NIBS), which includes transcranial magnetic stimulation (TMS) and... (Meta-Analysis)
Meta-Analysis Review
Based on existing evidence of the effects of the most commonly used non-invasive brain stimulation (NIBS), which includes transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS), we conducted a meta-analysis to investigate the cognitive improvement and safety of NIBS on schizophrenia-related cognitive impairment. PubMed, EMBASE, Cochrane Library, and Web of Science were searched. The Cochrane Risk of Bias tool was used to assess the risk of bias of the included RCTs; Review Manager, version 5.4.1, was used to perform the statistical analysis. Twenty double-blind, randomized, sham-controlled trials involving 997 patients were included. As a result, no significant improvement in cognitive function was observed after NIBS treatment. However, the overall treatment effect of the two main NIBS modes (i.e., rTMS and tDCS) was associated with significantly larger improvements in negative symptoms and good tolerability in patients with schizophrenia compared to sham-controls (SMD = -0.56, 95% CI [-1.03, -0.08], p = 0.02, I = 88%). NIBS model and stimulus parameters influenced the effect of NIBS. More favorable effects were observed in patients who received rTMS stimulation (SMD = 0.25, 95% CI [0.01, 0.49], p = 0.04, I = 0%) in the left dorsolateral prefrontal cortex with a stimulation intensity of 20 Hz (p = 0.004) for a period longer than 1 month (p < 0.05). Yet, due to the limited number of included studies and heterogeneity in both study design and target population, the results of this analysis need to be interpreted with caution.
Topics: Humans; Transcranial Direct Current Stimulation; Schizophrenia; Transcranial Magnetic Stimulation; Cognition; Cognitive Dysfunction; Brain; Randomized Controlled Trials as Topic
PubMed: 38150769
DOI: 10.1016/j.jpsychires.2023.12.003 -
Journal of Psychiatry & Neuroscience :... 2023Numerous neuroimaging studies using surface-based morphometry analyses have reported altered cortical thickness among patients with schizophrenia, but the results have... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Numerous neuroimaging studies using surface-based morphometry analyses have reported altered cortical thickness among patients with schizophrenia, but the results have been inconsistent. We sought to provide a whole-brain meta-analysis, which may help enhance the spatial accuracy of identification.
METHODS
We conducted a meta-analysis of whole-brain studies that explored cortical thickness alteration among adult patients with schizophrenia, including first-episode patients with schizophrenia, and patients with chronic schizophrenia, compared with healthy controls by using the seed-based d mapping with permutation of subject images (SDM-PSI) software.
RESULTS
A systematic literature search identified 25 studies (33 data sets) of cortical thickness, including 2008 patients with schizophrenia and 2004 healthy controls. Overall, patients with schizophrenia showed decreased cortical thickness in the right inferior frontal gyrus (IFG) and bilateral insula extending to the superior temporal gyrus (STG). Subgroup meta-analysis reported that patients with chronic schizophrenia showed decreased cortical thickness in the right insula extending to the right IFG. There was no significant cortical thickness difference between first-episode patients with schizophrenia and healthy controls.
LIMITATIONS
The results of meta-regression analyses should be viewed cautiously since they were driven by a small number of studies or did not overlap with the between-group differences found in the primary analyses.
CONCLUSION
The meta-analysis suggested robust cortical thickness reduction in the IFG, insula and STG among adult patients with schizophrenia, particularly in those with chronic schizophrenia. The results provide useful insights to understanding the underlying pathophysiology of schizophrenia.
Topics: Adult; Humans; Brain; Magnetic Resonance Imaging; Prefrontal Cortex; Schizophrenia; Temporal Lobe
PubMed: 38123240
DOI: 10.1503/jpn.230081 -
Neuropsychopharmacology : Official... Mar 2024While pharmacological, behavioral and psychosocial treatments are available for substance use disorders (SUDs), they are not always effective or well-tolerated.... (Meta-Analysis)
Meta-Analysis
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.
Topics: Humans; Transcranial Direct Current Stimulation; Transcranial Magnetic Stimulation; Substance-Related Disorders; Behavior, Addictive; Craving; Prefrontal Cortex
PubMed: 38086901
DOI: 10.1038/s41386-023-01776-0 -
Psychiatry Research Jan 2024Addiction is a substantial health concern; craving-the core symptom of addiction-is strongly associated with relapse. Transcranial direct current stimulation (tDCS) is a... (Meta-Analysis)
Meta-Analysis
Addiction is a substantial health concern; craving-the core symptom of addiction-is strongly associated with relapse. Transcranial direct current stimulation (tDCS) is a noninvasive brain stimulation technique that reduces cravings by altering cortical excitability and connectivity in brain regions. This systematic review and meta-analysis was conducted (following the PRISMA guidelines) to evaluate the efficacy of tDCS in reducing cravings for substances. Our analysis included 43 randomized, sham-controlled trials involving 1,095 and 913 participants receiving tDCS and sham stimulation, respectively. We analyzed the changes in craving scores and found that tDCS led to a moderate reduction in cravings compared with the sham effects. This effect was particularly pronounced when bilateral stimulation was used, the anodal electrode was placed on the right dorsolateral prefrontal cortex, current intensities ranged from 1.5 to 2 mA, stimulation sessions lasted 20 minutes, and the electrodes size was ≥35 cm². Notably, tDCS effectively reduced cravings for opioids, methamphetamine, cocaine, and tobacco but not for alcohol or cannabis. Our findings indicate tDCS as a promising, noninvasive, and low-risk intervention for reducing cravings for opioids, methamphetamine, cocaine, and tobacco. Additional studies are warranted to refine stimulation parameters and evaluate the long-term efficacy of tDCS in managing substance cravings.
Topics: Humans; Transcranial Direct Current Stimulation; Craving; Prefrontal Cortex; Substance-Related Disorders; Methamphetamine; Cocaine; Double-Blind Method
PubMed: 38043411
DOI: 10.1016/j.psychres.2023.115621 -
Neuroscience and Biobehavioral Reviews Jan 2024Mothers exposed to infections during pregnancy disproportionally birth children who develop autism and schizophrenia, disorders associated with altered GABAergic... (Review)
Review
Mothers exposed to infections during pregnancy disproportionally birth children who develop autism and schizophrenia, disorders associated with altered GABAergic function. The maternal immune activation (MIA) model recapitulates this risk factor, with many studies also reporting disruptions to GABAergic interneuron expression, protein, cellular density and function. However, it is unclear if there are species, sex, age, region, or GABAergic subtype specific vulnerabilities to MIA. Furthermore, to fully comprehend the impact of MIA on the GABAergic system a synthesised account of molecular, cellular, electrophysiological and behavioural findings was required. To this end we conducted a systematic review of GABAergic interneuron changes in the MIA model, focusing on the prefrontal cortex and hippocampus. We reviewed 102 articles that revealed robust changes in a number of GABAergic markers that present as gestationally-specific, region-specific and sometimes sex-specific. Disruptions to GABAergic markers coincided with distinct behavioural phenotypes, including memory, sensorimotor gating, anxiety, and sociability. Findings suggest the MIA model is a valid tool for testing novel therapeutics designed to recover GABAergic function and associated behaviour.
Topics: Male; Pregnancy; Female; Animals; Child; Humans; Rodentia; Interneurons; Prefrontal Cortex; Mothers; Behavior, Animal; Disease Models, Animal; Prenatal Exposure Delayed Effects
PubMed: 38042358
DOI: 10.1016/j.neubiorev.2023.105488 -
Cognitive, Affective & Behavioral... Feb 2024All experiences preserved within episodic memory contain information on the space and time of events. The hippocampus is the main brain region involved in processing... (Meta-Analysis)
Meta-Analysis Review
All experiences preserved within episodic memory contain information on the space and time of events. The hippocampus is the main brain region involved in processing spatial and temporal information for incorporation within episodic memory representations. However, the other brain regions involved in the encoding and retrieval of spatial and temporal information within episodic memory are unclear, because a systematic review of related studies is lacking and the findings are scattered. The present study was designed to integrate the results of functional magnetic resonance imaging and positron emission tomography studies by means of a systematic review and meta-analysis to provide converging evidence. In particular, we focused on identifying the brain regions involved in the retrieval of spatial and temporal information. We identified a spatial retrieval network consisting of the inferior temporal gyrus, parahippocampal gyrus, superior parietal lobule, angular gyrus, and precuneus. Temporal context retrieval was supported by the dorsolateral prefrontal cortex. Thus, the retrieval of spatial and temporal information is supported by different brain regions, highlighting their different natures within episodic memory.
Topics: Humans; Memory, Episodic; Brain Mapping; Brain; Temporal Lobe; Parietal Lobe; Magnetic Resonance Imaging; Mental Recall
PubMed: 38030912
DOI: 10.3758/s13415-023-01140-1