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Frontiers in Neuroscience 2024Olfaction is understudied in neuroimaging research compared to other senses, but there is growing evidence of its therapeutic benefits on mood and well-being. Olfactory... (Review)
Review
Olfaction is understudied in neuroimaging research compared to other senses, but there is growing evidence of its therapeutic benefits on mood and well-being. Olfactory imagery can provide similar health benefits as olfactory interventions. Harnessing crossmodal visual-olfactory interactions can facilitate olfactory imagery. Understanding and employing these cross-modal interactions between visual and olfactory stimuli could aid in the research and applications of olfaction and olfactory imagery interventions for health and wellbeing. This review examines current knowledge, debates, and research on olfaction, olfactive imagery, and crossmodal visual-olfactory integration. A total of 56 papers, identified using the PRISMA method, were evaluated to identify key brain regions, research themes and methods used to determine the suitability of fNIRS as a tool for studying these topics. The review identified fNIRS-compatible protocols and brain regions within the fNIRS recording depth of approximately 1.5 cm associated with olfactory imagery and crossmodal visual-olfactory integration. Commonly cited regions include the orbitofrontal cortex, inferior frontal gyrus and dorsolateral prefrontal cortex. The findings of this review indicate that fNIRS would be a suitable tool for research into these processes. Additionally, fNIRS suitability for use in naturalistic settings may lead to the development of new research approaches with greater ecological validity compared to existing neuroimaging techniques.
PubMed: 38356646
DOI: 10.3389/fnins.2024.1266664 -
Scientific Reports Jul 2023The neurobiological effects of mind-body exercise on brain activation, functional neural connections and structural changes in the brain remain elusive. This systematic... (Meta-Analysis)
Meta-Analysis
The neurobiological effects of mind-body exercise on brain activation, functional neural connections and structural changes in the brain remain elusive. This systematic review and coordinate-based meta-analysis investigated the changes in resting-state and task-based brain activation, as well as structural brain changes before and after mind-body exercise compared to waitlist or active controls based on published structural or functional magnetic resonance imaging randomized controlled trials or cross-sectional studies. Electronic database search and manual search in relevant publications yielded 34 empirical studies with low-to-moderate risk of bias (assessed by Cochrane risk-of-bias tool for randomized trials or Joanna Briggs Institute's critical appraisal checklist for analytical cross-sectional studies) that fulfilled the inclusion criteria, with 26 studies included in the narrative synthesis and 8 studies included in the meta-analysis. Coordinate-based meta-analysis showed that, while mind-body exercise enhanced the activation of the left anterior cingulate cortex within the default mode network (DMN), it induced more deactivation in the left supramarginal gyrus within the ventral attention network (uncorrected ps < 0.05). Meta-regression with duration of mind-body practice as a factor showed that, the activation of right inferior parietal gyrus within the DMN showed a positive association with increasing years of practice (voxel-corrected p < 0.005). Although mind-body exercise is shown to selectively modulate brain functional networks supporting attentional control and self-awareness, the overall certainty of evidence is limited by small number of studies. Further investigations are needed to understand the effects of both short-term and long-term mind-body exercise on structural changes in the brain.PROSPERO registration number: CRD42021248984.
Topics: Humans; Cross-Sectional Studies; Neuroimaging; Brain; Exercise Therapy; Magnetic Resonance Imaging
PubMed: 37415072
DOI: 10.1038/s41598-023-37309-4 -
Brain and Behavior Nov 2023Humans use discriminative touch to perceive texture through dynamic interactions with surfaces, activating low-threshold mechanoreceptors in the skin. It was largely... (Meta-Analysis)
Meta-Analysis
INTRODUCTION
Humans use discriminative touch to perceive texture through dynamic interactions with surfaces, activating low-threshold mechanoreceptors in the skin. It was largely assumed that texture was processed in primary somatosensory regions in the brain; however, imaging studies indicate heterogeneous patterns of brain activity associated with texture processing.
METHODS
To address this, we conducted a coordinate-based activation likelihood estimation meta-analysis of 13 functional magnetic resonance imaging studies (comprising 15 experiments contributing 228 participants and 275 foci) selected by a systematic review.
RESULTS
Concordant activations for texture perception occurred in the left primary somatosensory and motor regions, with bilateral activations in the secondary somatosensory, posterior insula, and premotor and supplementary motor cortices. We also evaluated differences between studies that compared touch processing to non-haptic control (e.g., rest or visual control) or those that used haptic control (e.g., shape or orientation perception) to specifically investigate texture encoding. Studies employing a haptic control revealed concordance for texture processing only in the left secondary somatosensory cortex. Contrast analyses demonstrated greater concordance of activations in the left primary somatosensory regions and inferior parietal cortex for studies with a non-haptic control, compared to experiments accounting for other haptic aspects.
CONCLUSION
These findings suggest that texture processing may recruit higher order integrative structures, and the secondary somatosensory cortex may play a key role in encoding textural properties. The present study provides unique insight into the neural correlates of texture-related processing by assessing the influence of non-textural haptic elements and identifies opportunities for a future research design to understand the neural processing of texture.
Topics: Humans; Brain Mapping; Likelihood Functions; Magnetic Resonance Imaging; Touch Perception
PubMed: 37749852
DOI: 10.1002/brb3.3264 -
Neuroscience and Biobehavioral Reviews May 2024The present review examined the consequences of focal brain injury on spatial attention studied with cueing paradigms, with a particular focus on the disengagement... (Review)
Review
The present review examined the consequences of focal brain injury on spatial attention studied with cueing paradigms, with a particular focus on the disengagement deficit, which refers to the abnormal slowing of reactions following an ipsilesional cue. Our review supports the established notion that the disengagement deficit is a functional marker of spatial neglect and is particularly pronounced when elicited by peripheral cues. Recent research has revealed that this deficit critically depends on cues that have task-relevant characteristics or are associated with negative reinforcement. Attentional capture by task-relevant cues is contingent on damage to the right temporo-parietal junction (TPJ) and is modulated by functional connections between the TPJ and the right insular cortex. Furthermore, damage to the dorsal premotor or prefrontal cortex (dPMC/dPFC) reduces the effect of task-relevant cues. These findings support an interactive model of the disengagement deficit, involving the right TPJ, the insula, and the dPMC/dPFC. These interconnected regions play a crucial role in regulating and adapting spatial attention to changing intrinsic values of stimuli in the environment.
Topics: Humans; Brain Injuries; Prefrontal Cortex; Perceptual Disorders; Cues; Space Perception; Parietal Lobe; Functional Laterality; Reaction Time
PubMed: 38490498
DOI: 10.1016/j.neubiorev.2024.105622 -
Chronic Stress (Thousand Oaks, Calif.) 2024Substance use disorder (SUD) is a significant health problem, and trauma exposure is a known risk factor for the escalation of substance use. However, the shared neural... (Review)
Review
Substance use disorder (SUD) is a significant health problem, and trauma exposure is a known risk factor for the escalation of substance use. However, the shared neural mechanisms through which trauma is associated with substance use are still unknown. Therefore, we systematically review neuroimaging studies focusing on three domains that may contribute to the overlapping mechanisms of SUD and trauma-reward salience, negative emotionality, and inhibition. Using PRISMA guidelines, we identified 45 studies utilizing tasks measuring these domains in alcohol, tobacco, and cannabis use groups. Greater reward, lesser regulation of inhibitory processes, and mixed findings of negative emotionality processes in individuals who use substances versus controls were found. Specifically, greater orbitofrontal cortex, ventral tegmental area, striatum, amygdala, and hippocampal activation was found in response to reward-related tasks, and reduced activation was found in the inferior frontal gyrus and hippocampus in response to inhibition-related tasks. Importantly, no studies in trauma-exposed individuals met our review criteria. Future studies examining the role of trauma-related factors are needed, and more studies should explore inhibition- and negative-emotionality domains in individuals who use substances to uncover clinically significant alterations in these domains that place an individual at greater risk for developing a SUD.
PubMed: 38846598
DOI: 10.1177/24705470241258752 -
Reviews in Endocrine & Metabolic... Aug 2023Disinhibited eating involves overconsumption and loss of control over food intake, and underpins many health conditions, including obesity and binge-eating related...
Disinhibited eating involves overconsumption and loss of control over food intake, and underpins many health conditions, including obesity and binge-eating related disorders. Stress has been implicated in the development and maintenance of disinhibited eating behaviours, but the mechanisms underlying this relationship are unclear. In this systematic review, we examined how the impact of stress on the neurobiological substrates of food-related reward sensitivity, interoception and cognitive control explains its role in disinhibited eating behaviours. We synthesised the findings of functional magnetic resonance imaging studies including acute and/or chronic stress exposures in participants with disinhibited eating. A systematic search of existing literature conducted in alignment with the PRISMA guidelines identified seven studies investigating neural impacts of stress in people with disinhibited eating. Five studies used food-cue reactivity tasks, one study used a social evaluation task, and one used an instrumental learning task to probe reward, interoception and control circuitry. Acute stress was associated with deactivation of regions in the prefrontal cortex implicated in cognitive control and the hippocampus. However, there were mixed findings regarding differences in reward-related circuitry. In the study using a social task, acute stress associated with deactivation of prefrontal cognitive control regions in response to negative social evaluation. In contrast, chronic stress was associated with both deactivation of reward and prefrontal regions when viewing palatable food-cues. Given the small number of identified publications and notable heterogeneity in study designs, we propose several recommendations to strengthen future research in this emerging field.
Topics: Humans; Binge-Eating Disorder; Eating; Feeding Behavior; Magnetic Resonance Imaging; Obesity; Reward
PubMed: 37310550
DOI: 10.1007/s11154-023-09814-4 -
Brain Sciences Mar 2024Mild cognitive impairment (MCI) is a transitional or prodromal stage of dementia in which autonomies are largely preserved (autonomies are not particularly affected).... (Review)
Review
Mild cognitive impairment (MCI) is a transitional or prodromal stage of dementia in which autonomies are largely preserved (autonomies are not particularly affected). However, this condition may entail a depletion of decision-making (DM) abilities likely due to a gradual deterioration of the prefrontal cortex and subcortical brain areas underlying cognitive-emotional processing. Given the clinical implications of a decline in self-determination observed in some MCI sufferers, the present systematic review was aimed at investigating the literature addressing DM processes in patients with MCI, consistent with PRISMA guidelines. The six online databases inquired yielded 1689 research articles that were screened and then assessed based on eligibility and quality criteria. As a result, 41 studies were included and classified following the PICOS framework. Overall, patients with MCI who underwent neuropsychological assessment were found to be slightly or moderately impaired in DM abilities related to financial management, medical adherence, specific cognitive performances, risky conditions, and especially uncertain life circumstances. Comparative cross-sectional studies indicated not only mid-stage cognitive functioning in MCI but also borderline or deficit DM patterns evaluated through different tasks and procedures. Further research addressing MCI profiles suggested an association between explicit memory, executive functions, and DM performance. These findings highlight the diversity of MCI manifestations, in addition to the critical importance of DM features and correlates in patients' daily functioning. Due to a lack of consensus on both MCI and DM, this review paper sought to shed light on assessment and intervention strategies accounting for the interplay between emotion, motivation, and learning to foster DM in cognitively impaired individuals.
PubMed: 38539666
DOI: 10.3390/brainsci14030278 -
PloS One 2023Olfactory dysfunction is a common manifestation in COVID-19 patients and can significantly impact their quality of life. Corticosteroids have been proposed as a... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Olfactory dysfunction is a common manifestation in COVID-19 patients and can significantly impact their quality of life. Corticosteroids have been proposed as a potential treatment, but their efficacy remains controversial. This systematic review and meta-analysis aims to comprehensively analyze the efficacy of corticosteroid therapy for treating COVID-19-related olfactory dysfunction.
METHODS
A literature search was conducted in PubMed, Cochrane Library, and Embase databases up to March 1, 2023. Randomized controlled trials investigating the effects of corticosteroids on olfactory dysfunction in patients with COVID-19 were included. The primary outcome was the olfactory score at the end of follow-up, and the secondary outcomes were the duration and the rate of recovery from olfactory dysfunction.
RESULTS
Seven randomized controlled trials with 999 participants were included in the meta-analysis. Compared with the control group, corticosteroid treatment resulted in a statistically significant improvement in olfactory score with a standardized mean difference of 0.55 (95% CI: 0.15 to 0.95). Topical corticosteroids were found to be effective, but systemic corticosteroids were not. In addition, longer durations and higher dosages of corticosteroids treatment may also be associated with significant improvements in olfactory scores. No significant effect was observed on the duration or recovery rate of olfactory dysfunction.
CONCLUSIONS
Our findings suggest that topical corticosteroid treatment is a viable option for improving COVID-19-related olfactory dysfunction, but further research is needed to investigate optimal treatment protocols and safety profiles.
Topics: Humans; Quality of Life; COVID-19; Randomized Controlled Trials as Topic; Adrenal Cortex Hormones; Glucocorticoids; Olfaction Disorders
PubMed: 38127940
DOI: 10.1371/journal.pone.0289172 -
Frontiers in Immunology 2024Lichen planus pemphigoides (LPP), an association between lichen planus and bullous pemphigoid lesions, is a rare subepithelial autoimmune bullous disease. Mucous...
BACKGROUND
Lichen planus pemphigoides (LPP), an association between lichen planus and bullous pemphigoid lesions, is a rare subepithelial autoimmune bullous disease. Mucous membrane involvement has been reported previously; however, it has never been specifically studied.
METHODS
We report on 12 cases of LPP with predominant or exclusive mucous membrane involvement. The diagnosis of LPP was based on the presence of lichenoid infiltrates in histology and immune deposits in the basement membrane zone in direct immunofluorescence and/or immunoelectron microscopy. Our systematic review of the literature, performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, highlights the clinical and immunological characteristics of LPP, with or without mucous membrane involvement.
RESULTS
Corticosteroids are the most frequently used treatment, with better outcomes in LPP with skin involvement alone than in that with mucous membrane involvement. Our results suggest that immunomodulators represent an alternative first-line treatment for patients with predominant mucous membrane involvement.
Topics: Adult; Aged; Aged, 80 and over; Female; Humans; Male; Middle Aged; Adrenal Cortex Hormones; Lichen Planus; Mucous Membrane; Pemphigoid, Bullous
PubMed: 38686381
DOI: 10.3389/fimmu.2024.1243566 -
Clinical and Experimental Rheumatology Apr 2024To describe the phenotypic, genetic, and outcome characteristics of large-vessel vasculopathy (LVV) in childhood associated with genetic variants. Additionally, a...
OBJECTIVES
To describe the phenotypic, genetic, and outcome characteristics of large-vessel vasculopathy (LVV) in childhood associated with genetic variants. Additionally, a systematic literature review was conducted to delineate the differences between LVV with and without genetic variants.
METHODS
The medical records of all children with LVV seen between January 2000 and September 2022 at our institution were retrospectively reviewed for demographic, clinical and genetic data, and outcomes at the last follow-up visit. In addition, we systematically reviewed the literature for the clinical features and known variants of previously reported cases.
RESULTS
Eleven patients with childhood LVV were identified; five (three males) of them had proven genetic variants (two DOCK8variants, one FOXP3, one DiGeorge syndrome, and one ZNF469 variant), while six patients had sporadic childhood LVV. Remarkably, patients with genetic variants were younger and had early-onset disease. However, the diagnosis of LVV was delayed compared to those without genetic variants. All patients with genetic variants were treated with corticosteroids, and three patients required sequential immunosuppressive drugs. Four patients underwent surgical intervention, and one received a haematopoietic stem-cell transplant (HSCT). Three patients achieved clinical remission, and two died. Furthermore, data from 20 previously published cases was extracted from the literature. All patients had inherited disorders. Of those, 14 patients had a genetically proven diagnosis. Most of them are treated with corticosteroids and immunosuppressive drugs, with partial responses. Two patients underwent HSCT. There were four deaths.
CONCLUSIONS
This study demonstrates that a variety of inherited disorders may contribute to childhood LVV. Strong genetic evidence and the preponderance of autosomal-recessive inheritance may allow us to propose that monogenic LVV is a distinct entity.
Topics: Humans; Phenotype; Male; Child; Female; Child, Preschool; Genetic Predisposition to Disease; Adolescent; Immunosuppressive Agents; Genetic Variation; Retrospective Studies; Infant; Treatment Outcome; Risk Factors; Adrenal Cortex Hormones; Vascular Diseases; Age of Onset; Forkhead Transcription Factors; Hematopoietic Stem Cell Transplantation; Guanine Nucleotide Exchange Factors; DNA-Binding Proteins
PubMed: 37404170
DOI: 10.55563/clinexprheumatol/je8rq2