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1.
Front Psychiatry ; 14: 1184797, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37275967

RESUMO

Background: Functional dyspepsia (FD) is most often a meal-induced syndrome. Studies using resting-state functional magnetic resonance imaging (rs-fMRI) reported abnormal connectivity in areas related to pain processing in FD. However, only a few studies have attempted to determine how meal ingestion affects the brain's working patterns. Through rs-fMRI, this study observed how meal ingestion affected brain regions related to visceral hypersensitivity and emotional response networks in FD patients. Methods: A total of 30 FD patients and 32 healthy controls (HC) were enrolled and underwent clinical investigations. Rs-fMRI was performed twice after a 4-h fast and 50 min after a meal. The mean functional connectivity strength (FCS) values were extracted from brain regions with significant differences to show the trend of changes related to meal ingestion after FCS analyses. Results: Depression, anxiety, sleep disturbances, and weight loss were more common in FD patients (P ≤ 0.001). Compared with HCs (corrected cluster P-value < 0.05), FD patients had significantly higher FCS in the right middle frontal gyrus before meals and higher meal-induced FCS in the left postcentral gyrus. HCs had greater meal-induced activation in the right precuneus and anterior cingulate cortex. FD patients had a decreasing trend in the right inferior frontal gyrus compared to the increasing trend in HCs. We only found anxiety to be negatively correlated with FCS in the right inferior frontal gyrus in FD (r = -0.459, p = 0.048, uncorrected). Conclusions: In this study, we discovered that FD patients have different perceptual and emotional responses to food intake in defined brain areas, providing promising impetus for understanding pathogenic brain mechanisms in FD.

2.
Front Psychol ; 13: 910767, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36275204

RESUMO

This paper explores the positive impact of viewing a virtual art exhibit on mood during the COVID-19 Pandemic. During global lockdowns, depression, anxiety, and the burden of other mental illnesses have increased even among prior psychiatrically healthy individuals. Art and music-based interventions have shown to be effective clinical interventions in individuals with mental illness. The VisualEars project explored whether a virtual activity involving vision and auditory stimuli could improve positive and negative affect. Eight musical pieces were selected, and 28 visual artists from around the world visualized two musical pieces. A total of 56 works of art were created and hung in eight 3D virtual rooms. Visitors were randomly selected to either view the art exhibit without music (non-immersive) or view the art exhibit while listening to music (immersive). Visitors were asked to complete a positive and negative affect schedule (PANAS) in three languages (English, French, and Farsi) pre and post their virtual visit. A total of 160 participants completed baseline PANAS, 58 of which completed the follow-up PANAS. Linear mixed-effects models found that older participants had lower negative affect scores overall (b = -0.3, p = 0.003), while male participants had lower positive affect scores overall (b = -0.27, p = 0.02). Following the virtual exhibit participants of both conditions had higher positive (b = 0.17, p = 0.03), and lower negative affect scores (b = -0.19, p = 0.007). We found that the virtual art exhibit increased positive affect and decreased negative affect in participants, suggesting an overall improvement in mood attributable to the virtual exhibit. This suggests that virtual exhibits may serve as a beneficial and accessible intervention to improve mood during a pandemic.

3.
Brain Sci ; 11(7)2021 Jul 07.
Artigo em Inglês | MEDLINE | ID: mdl-34356129

RESUMO

Parkinson's disease (PD) is a neurodegenerative disease that has a fast progression of motor dysfunction within the first 5 years of diagnosis, showing an annual motor rate of decline of the Movement Disorder Society Unified Parkinson's Disease Rating Scale (MDS-UPDRS) between 5.2 and 8.9 points. We aimed to determine both motor and non-motor PD symptom progression while participating in dance classes once per week over a period of three years. Longitudinal data was assessed for a total of 32 people with PD using MDS-UPDRS scores. Daily motor rate of decline was zero (slope = 0.000146) in PD-Dancers, indicating no motor impairment, whereas the PD-Reference group showed the expected motor decline across three years (p < 0.01). Similarly, non-motor aspects of daily living, motor experiences of daily living, and motor complications showed no significant decline. A significant group (PD-Dancers and PD-Reference) by days interaction showed that PD who train once per week have less motor impairment (M = 18.75) than PD-References who do not train (M = 24.61) over time (p < 0.05). Training is effective at slowing both motor and non-motor PD symptoms over three years as shown in decreased scores of the MDS-UPDRS.

4.
Eur J Neurosci ; 54(12): 8355-8363, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-32544262

RESUMO

Neuroscience of dance is an emerging field with important applications related to health and well-being, as dance has shown potential to foster adaptive neuroplasticity and is increasingly popular as a therapeutic activity or adjunct therapy for people living with conditions such as Parkinson's and Alzheimer's diseases. However, the multimodal nature of dance presents challenges to researchers aiming to identify mechanisms involved when dance is used to combat neurodegeneration or support healthy ageing. Requiring simultaneous engagement of motor and cognitive domains, dancing includes coordination of systems involved in timing, memory and spatial learning. Studies on dance to this point rely primarily on assessments of brain dynamics and structure through pre/post-tests or studies on expertise, as traditional brain imaging modalities restrict participant movement to avoid movement-related artefacts. In this paper, we describe the process of designing and implementing a study that uses mobile brain/body imaging (MoBI) to investigate real-time changes in brain dynamics and behaviour during the process of learning and performing a novel dance choreography. We show the potential for new insights to emerge from the coordinated collection of movement and brain-based data, and the implications of these in an emerging field whose medium is motion.


Assuntos
Encéfalo , Movimento , Encéfalo/diagnóstico por imagem , Humanos , Aprendizagem
5.
Vision (Basel) ; 4(3)2020 Aug 10.
Artigo em Inglês | MEDLINE | ID: mdl-32785006

RESUMO

By chunking continuous streams of action into ordered, discrete, and meaningful units, event segmentation facilitates motor learning. While expertise in the observed repertoire reduces the frequency of event borders, generalization of this effect to unfamiliar genres of dance and among other sensorimotor experts (musicians, athletes) remains unknown, and was the first aim of this study. Due to significant overlap in visuomotor, language, and memory processing brain networks, the second aim of this study was to investigate whether visually priming expert motor schemas improves memory for words related to one's expertise. A total of 112 participants in six groups (ballet, Bharatanatyam, and "other" dancers, athletes, musicians, and non-experts) segmented a ballet dance, a Bharatanatyam dance, and a non-dance control sequence. To test verbal memory, participants performed a retrieval-induced forgetting task between segmentation blocks. Dance, instrument, and sport word categories were included to probe the second study aim. Results of the event segmentation paradigm clarify that previously-established expert segmentation effects are specific to familiar genres of dance, and do not transfer between different types of experts or to non-dance sequences. Greater recall of dance category words among ballet and Bharatanatyam dancers provides novel evidence for improved verbal memory primed by activating familiar sensorimotor representations.

6.
Front Neurol ; 11: 364, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32477243

RESUMO

Background: Early stage (preclinical) detection of Parkinson's disease (PD) remains challenged yet is crucial to both differentiate it from other disorders and facilitate timely administration of neuroprotective treatment as it becomes available. Objective: In a cross-validation paradigm, this work focused on two binary predictive probability analyses: classification of early PD vs. controls and classification of early PD vs. SWEDD (scans without evidence of dopamine deficit). It was hypothesized that five distinct model types using combined non-motor and biomarker features would distinguish early PD from controls with > 80% cross-validated (CV) accuracy, but that the diverse nature of the SWEDD category would reduce early PD vs. SWEDD CV classification accuracy and alter model-based feature selection. Methods: Cross-sectional, baseline data was acquired from the Parkinson's Progressive Markers Initiative (PPMI). Logistic regression, general additive (GAM), decision tree, random forest and XGBoost models were fitted using non-motor clinical and biomarker features. Randomized train and test data partitions were created. Model classification CV performance was compared using the area under the curve (AUC), sensitivity, specificity and the Kappa statistic. Results: All five models achieved >0.80 AUC CV accuracy to distinguish early PD from controls. The GAM (CV AUC 0.928, sensitivity 0.898, specificity 0.897) and XGBoost (CV AUC 0.923, sensitivity 0.875, specificity 0.897) models were the top classifiers. Performance across all models was consistently lower in the early PD/SWEDD analyses, where the highest performing models were XGBoost (CV AUC 0.863, sensitivity 0.905, specificity 0.748) and random forest (CV AUC 0.822, sensitivity 0.809, specificity 0.721). XGBoost detection of non-PD SWEDD matched 1-2 years curated diagnoses in 81.25% (13/16) cases. In both early PD/control and early PD/SWEDD analyses, and across all models, hyposmia was the single most important feature to classification; rapid eye movement behavior disorder (questionnaire) was the next most commonly high ranked feature. Alpha-synuclein was a feature of import to early PD/control but not early PD/SWEDD classification and the Epworth Sleepiness scale was antithetically important to the latter but not former. Interpretation: Non-motor clinical and biomarker variables enable high CV discrimination of early PD vs. controls but are less effective discriminating early PD from SWEDD.

7.
Front Psychol ; 11: 600440, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33613357

RESUMO

Background: Previous studies have investigated the effects of dance interventions on Parkinson's motor and non-motor symptoms in an effort to develop an integrated view of dance as a therapeutic intervention. This within-subject study questions whether dance can be simply considered a form of exercise by comparing a Dance for Parkinson's class with a matched-intensity exercise session lacking dance elements like music, metaphorical language, and social reality of art-partaking. Methods: In this repeated-measure design, 7 adults with Parkinson's were tested four times; (i) before and (ii) after a Dance for Parkinson's class, as well as (iii) before and (iv) after a matched-intensity exercise session. Physiological measures included heart rate and electrodermal activity. Self-reported affect and body self-efficacy were collected. Gait symmetry and dual task cost were analyzed using the 6 min walking test (6MWT) and Timed-Up-and-Go test (TUG), respectively. Results: Average heart rate was the same for both conditions, while electrodermal activity was higher during Dance for Parkinson's. Significant differences were found in body self-efficacy, beauty subscale, symmetry of gait, and dual task performance. Conclusion: Dance, compared to an exercise intervention of matched intensity, yields different outcomes through the means of intrinsic artistic elements, which may influence affective responses, the experience of beauty, self-efficacy, and gait performance.

8.
Front Neurol ; 8: 68, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28373854

RESUMO

INTRODUCTION: Change in migraine headache (MH)-preexisting MH change or development of de novo MH-are known potential complications following percutaneous closure of atrial septal defect (ASD), but consensus on a causal trigger remains elusive. OBJECTIVES: To expose potential MH triggers linked, mainly by timing and occurrence, to the emergence of de novo MH or change in preexisting MH subsequent to percutaneous ASD closure (pASDC). METHODS: The literature was systematically searched for studies available in English reporting MH status after pASDC published between January 1, 1990 and November 15, 2015. We determined the number and percentage of patients experiencing MH status change within 7 days post procedure and the cumulative total by final follow-up (Mdn = 12 months). RESULTS: Twenty-five studies met the inclusion criteria, which accounted for a total of 1,646 pASDC patients. Pre-procedure MH prevalence was 8% (126/1,646). Change in preexisting MH occurred in a total of 72% (91/126), 12% (11/91) within 7-days after pASDC; within follow-up MH improved in 14% (18/126), resolved in 37% (47/126), but persisted in 63% (79/126). De novo MH incidence ranged between 10 (153/1,520) and 18.3% (153/836); 34% incipience (52/153) was within 7-days of pASDC; females accounted for 80% (63/79) of gender differentiated cases; of type distinguished cases, 42% (51/122) were MH without aura (MO) and 58% (71/122) were MH with aura (MA); MH improved in 10% (16/153), resolved in 24% (37/153) but persisted beyond final follow-up in 76% (116/153). Antiplatelet agents were effective modulators of MH in 44% (11/25) studies. Possible adverse MH-predisposing traits were scarce: larger ASD size reported in ~2% (39/1,646) of patients experiencing de novo MH or preexisting MH exacerbation; short aortic rim reported in three de novo MH patients; allergic response to occluder nickel alloy in four patients with MH status change from baseline (de novo or preexisting MH change not specified). INTERPRETATION: Early intensification of MH status change but later amelioration (virtually paralleling stages of endothelialization), relatively high efficacy of antiplatelet agents, and the emergence of MA as the dominant de novo MH type favor proinflammatory triggers of MH status change after pASDC.

9.
BMC Neurosci ; 18(1): 28, 2017 03 06.
Artigo em Inglês | MEDLINE | ID: mdl-28264664

RESUMO

BACKGROUND: EEG studies investigating the neural networks that facilitate action observation (AO) and kinaesthetic motor imagery (KMI) have shown reduced, or desynchronized, power in the alpha (8-12 Hz) and beta (13-30 Hz) frequency bands relative to rest, reflecting efficient activation of task-relevant areas. Functional modulation of these networks through expertise in dance has been established using fMRI, with greater activation among experts during AO. While there is evidence for experience-dependent plasticity of alpha power during AO of dance, the influence of familiarity on beta power during AO, and alpha and beta activity during KMI, remain unclear. The purpose of the present study was to measure the impact of familiarity on confidence ratings and EEG activity during (1) AO of a brief ballet sequence, (2) KMI of this same sequence, and (3) KMI of non-dance movements among ballet dancers, dancers from other genres, and non-dancers. RESULTS: Ballet dancers highly familiar with the genre of the experimental stimulus demonstrated higher individual alpha peak frequency (iAPF), greater alpha desynchronization, and greater task-related beta power during AO, as well as faster iAPF during KMI of non-dance movements. While no between-group differences in alpha or beta power were observed during KMI of dance or non-dance movements, all participants showed significant desynchronization relative to baseline, and further desynchronization during dance KMI relative to non-dance KMI indicative of greater cognitive load. CONCLUSIONS: These findings confirm and extend evidence for experience-dependent plasticity of alpha and beta activity during AO of dance and KMI. We also provide novel evidence for modulation of iAPF that is faster when tuned to the specific motor repertoire of the observer. By considering the multiple functional roles of these frequency bands during the same task (AO), we have disentangled the compounded contribution of familiarity and expertise to alpha desynchronization for mediating task engagement among familiar ballet dancers and reflecting task difficulty among unfamiliar non-dance subjects, respectively. That KMI of a complex dance sequence relative to everyday, non-dance movements recruits greater cognitive resources suggests it may be a more powerful tool in driving neural plasticity of action networks, especially among the elderly and those with movement disorders.


Assuntos
Encéfalo/fisiologia , Dança/fisiologia , Imaginação/fisiologia , Percepção de Movimento/fisiologia , Atividade Motora/fisiologia , Reconhecimento Psicológico/fisiologia , Ritmo alfa , Análise de Variância , Ritmo beta , Feminino , Humanos , Masculino , Prática Psicológica , Competência Profissional , Adulto Jovem
10.
Exp Brain Res ; 234(7): 2007-2023, 2016 07.
Artigo em Inglês | MEDLINE | ID: mdl-26960739

RESUMO

The lateral occipitotemporal cortex (LOTC) is comprised of subregions selectively activated by images of human bodies (extrastriate body area, EBA), objects (lateral occipital complex, LO), and motion (MT+). However, their role in motor imagery and movement processing is unclear, as are the influences of learning and expertise on its recruitment. The purpose of our study was to examine putative changes in LOTC activation during action processing following motor learning of novel choreography in professional ballet dancers. Subjects were scanned with functional magnetic resonance imaging up to four times over 34 weeks and performed four tasks: viewing and visualizing a newly learned ballet dance, visualizing a dance that was not being learned, and movement of the foot. EBA, LO, and MT+ were activated most while viewing dance compared to visualization and movement. Significant increases in activation were observed over time in left LO only during visualization of the unlearned dance, and all subregions were activated bilaterally during the viewing task after 34 weeks of performance, suggesting learning-induced plasticity. Finally, we provide novel evidence for modulation of EBA with dance experience during the motor task, with significant activation elicited in a comparison group of novice dancers only. These results provide a composite of LOTC activation during action processing of newly learned ballet choreography and movement of the foot. The role of these areas is confirmed as primarily subserving observation of complex sequences of whole-body movement, with new evidence for modification by experience and over the course of real world ballet learning.


Assuntos
Mapeamento Encefálico/métodos , Dança/fisiologia , Imaginação/fisiologia , Aprendizagem/fisiologia , Atividade Motora/fisiologia , Lobo Occipital/fisiologia , Lobo Temporal/fisiologia , Percepção Visual/fisiologia , Adolescente , Adulto , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Adulto Jovem
11.
PLoS One ; 11(1): e0147731, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26824475

RESUMO

Our knowledge of neural plasticity suggests that neural networks show adaptation to environmental and intrinsic change. In particular, studies investigating the neuroplastic changes associated with learning and practicing motor tasks have shown that practicing such tasks results in an increase in neural activation in several specific brain regions. However, studies comparing experts and non-experts suggest that experts employ less neuronal activation than non-experts when performing a familiar motor task. Here, we aimed to determine the long-term changes in neural networks associated with learning a new dance in professional ballet dancers over 34 weeks. Subjects visualized dance movements to music while undergoing fMRI scanning at four time points over 34-weeks. Results demonstrated that initial learning and performance at seven weeks led to increases in activation in cortical regions during visualization compared to the first week. However, at 34 weeks, the cortical networks showed reduced activation compared to week seven. Specifically, motor learning and performance over the 34 weeks showed the typical inverted-U-shaped function of learning. Further, our result demonstrate that learning of a motor sequence of dance movements to music in the real world can be visualized by expert dancers using fMRI and capture highly significant modeled fits of the brain network variance of BOLD signals from early learning to expert level performance.


Assuntos
Encéfalo/fisiologia , Dança/psicologia , Atividade Motora/fisiologia , Música/psicologia , Rede Nervosa/fisiologia , Plasticidade Neuronal/fisiologia , Adulto , Encéfalo/anatomia & histologia , Exercício Físico/fisiologia , Feminino , Humanos , Curva de Aprendizado , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Modelos Neurológicos , Rede Nervosa/anatomia & histologia
12.
Iperception ; 6(1): 1-4, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26034566

RESUMO

The brain shifts attention by selectively modulating sensory information about relevant environmental features. It has been shown that eye, head, trunk and limb position can bias spatial attention. This leads to the interesting question: Does the brain only recruit bodily information that is explicitly related to orienting behaviour to direct attention, or more generally? We tested whether tongue position, which does not explicitly functionally relate to orienting behaviour, biases attention in a visual search task. Thirty-six participants completed three visual search trial blocks of increased difficulty each consisting of three tongue positions for 50 trials. Response times and error rates were used to assess whether tongue position modulates visual attention. Results show that sensorimotor information from the tongue modulates attention in a difficult visual search task: faster responses to visual search targets presented ipsilateral with the tongue; slower responses when contralateral. In line with cognition being generally embodied, the tongue plays a surprising role in directing attention.

13.
J Cogn Neurosci ; 27(9): 1789-800, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-25941872

RESUMO

Performing multiple tasks concurrently places a load on limited attentional resources and results in disrupted task performance. Although human neuroimaging studies have investigated the neural correlates of attentional load, how attentional load affects task processing is poorly understood. Here, task-related neural activity was investigated using fMRI with conventional univariate analysis and multivariate pattern analysis (MVPA) while participants performed blocks of prosaccades and antisaccades, either with or without a rapid serial visual presentation (RSVP) task. Performing prosaccades and antisaccades with RSVP increased error rates and RTs, decreased mean activation in frontoparietal brain areas associated with oculomotor control, and eliminated differences in activation between prosaccades and antisaccades. However, task identity could be decoded from spatial patterns of activation both in the absence and presence of an attentional load. Furthermore, in the FEFs and intraparietal sulcus, these spatial representations were found to be similar using cross-trial-type MVPA, which suggests stability under attentional load. These results demonstrate that attentional load may disrupt the strength of task-related neural activity, rather than the identity of task representations.


Assuntos
Atenção/fisiologia , Encéfalo/fisiologia , Função Executiva/fisiologia , Atividade Motora/fisiologia , Movimentos Sacádicos/fisiologia , Adulto , Mapeamento Encefálico , Discriminação Psicológica/fisiologia , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Análise Multivariada , Testes Neuropsicológicos , Tempo de Reação , Adulto Jovem
14.
Neurocase ; 21(5): 607-17, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25301352

RESUMO

The current study used functional magnetic resonance imaging to examine the neural activity of an expert dancer with 35 years of break-dancing experience during the kinesthetic motor imagery (KMI) of dance accompanied by highly familiar and unfamiliar music. The goal of this study was to examine the effect of musical familiarity on neural activity underlying KMI within a highly experienced dancer. In order to investigate this in both primary sensory and motor planning cortical areas, we examined the effects of music familiarity on the primary auditory cortex [Heschl's gyrus (HG)] and the supplementary motor area (SMA). Our findings reveal reduced HG activity and greater SMA activity during imagined dance to familiar music compared to unfamiliar music. We propose that one's internal representations of dance moves are influenced by auditory stimuli and may be specific to a dance style and the music accompanying it.


Assuntos
Córtex Auditivo/fisiologia , Dança/fisiologia , Imaginação/fisiologia , Córtex Motor/fisiologia , Desempenho Psicomotor/fisiologia , Percepção Auditiva/fisiologia , Mapeamento Encefálico , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Música , Competência Profissional , Reconhecimento Psicológico/fisiologia
15.
Front Psychol ; 5: 1478, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25674066

RESUMO

Neurorehabilitation programs are commonly employed with the goal to help restore functionality in patients. However, many of these therapies report only having a small impact. In response to the need for more effective and innovative approaches, rehabilitative methods that take advantage of the neuroplastic properties of the brain have been used to aid with both physical and cognitive impairments. Following this path of reasoning, there has been a particular interest in the use of physical exercise as well as musical related activities. Although such therapies demonstrate potential, they also have limitations that may affect their use, calling for further exploration. Here, we propose dance as a potential parallel to physical and music therapies. Dance may be able to aid with both physical and cognitive impairments, particularly due to it combined nature of including both physical and cognitive stimulation. Not only does it incorporate physical and motor skill related activities, but it can also engage various cognitive functions such as perception, emotion, and memory, all while done in an enriched environment. Other more practical benefits, such as promoting adherence due to being enjoyable, are also discussed, along with the current literature on the application of dance as an intervention tool, as well as future directions required to evaluate the potential of dance as an alternative therapy in neurorehabilitation.

16.
Exp Brain Res ; 227(3): 301-9, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23660740

RESUMO

Everyday life requires the ability to flexibly switch between tasks. Often, task switching is accompanied by concurrent cognitive activities that compete for limited attentional resources. This study aimed to characterize the effects of attentional load on task switching. In experiment 1, participants performed an interleaved pro-saccade and anti-saccade task. In experiment 2, participants performed an interleaved pro-saccade and anti-saccade task simultaneously with a rapid serial visual presentation task that has been shown to create an attentional load. Error rates and reaction times of pro-saccades and anti-saccades were analysed for both experiments separately and together. Overall, error rates and reaction times increased with attentional load. With attentional load, switches to pro-saccades were associated with increased error rates and reaction times, whereas switches to anti-saccades were only associated with increased error rates. We propose that attentional load interferes with neural task-set representation and that the resulting executive control is different for the dominant and non-dominant task.


Assuntos
Atenção/fisiologia , Desempenho Psicomotor/fisiologia , Movimentos Sacádicos/fisiologia , Percepção Visual/fisiologia , Adulto , Sinais (Psicologia) , Feminino , Fixação Ocular/fisiologia , Humanos , Masculino , Estimulação Luminosa , Tempo de Reação/fisiologia
17.
Front Neurosci ; 7: 73, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23675314

RESUMO

In this paper we propose an agglomerative hierarchical clustering Ward's algorithm in tandem with the Affinity Propagation algorithm to reliably localize active brain regions from magnetoencephalography (MEG) brain signals. Reliable localization of brain areas with MEG has been difficult due to variations in signal strength, and the spatial extent of the reconstructed activity. The proposed approach to resolve this difficulty is based on adaptive clustering on reconstructed beamformer images to find locations that are consistently active across different participants and experimental conditions with high spatial resolution. Using data from a human reaching task, we show that the method allows more accurate and reliable localization from MEG data alone without using functional magnetic resonance imaging (fMRI) or any other imaging techniques.

18.
PLoS One ; 8(3): e59244, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23527146

RESUMO

Eye exercises have been prescribed to resolve a multitude of eye-related problems. However, studies on the efficacy of eye exercises are lacking, mainly due to the absence of simple assessment tools in the clinic. Because similar regions of the brain are responsible for eye movements and visual attention, we used a modified rapid serial visual presentation (RSVP) to assess any measurable effect of short-term eye exercise in improvements within these domains. In the present study, twenty subjects were equally divided into control and experimental groups, each of which performed a pre-training RSVP assessment where target letters, to which subjects were asked to respond to by pressing a spacebar, were serially and rapidly presented. Response time to target letters, accuracy of correctly responding to target letters, and correct identification of target letters in each of 12 sessions was measured. The experimental group then performed active eye exercises, while the control group performed a task that minimized eye movements for 18.5 minutes. A final post-training RSVP assessment was performed by both groups and response time, accuracy, and letter identification were compared between and within subject groups both pre- and post-training. Subjects who performed eye exercises were more accurate in responding to target letters separated by one distractor and in letter identification in the post-training RSVP assessment, while latency of responses were unchanged between and within groups. This suggests that eye exercises may prove useful in enhancing cognitive performance on tasks related to attention and memory over a very brief course of training, and RSVP may be a useful measure of this efficacy. Further research is needed on eye exercises to determine whether they are an effective treatment for patients with cognitive and eye-related disorders.


Assuntos
Exercício Físico/fisiologia , Movimentos Oculares/fisiologia , Reconhecimento Visual de Modelos/fisiologia , Adulto , Cognição/fisiologia , Inglaterra , Feminino , Humanos , Masculino , Estimulação Luminosa , Desempenho Psicomotor/fisiologia , Tempo de Reação/fisiologia
19.
Vision Res ; 76: 124-33, 2013 Jan 14.
Artigo em Inglês | MEDLINE | ID: mdl-23159418

RESUMO

Efference copy signals are used to reduce cognitive load by decreasing sensory processing of reafferent information (those incoming sensory signals that are produced by an organism's own motor output). Attenuated sensory processing of self-generated afferents is seen across species and in multiple sensory systems involving many different neural structures and circuits including both cortical and subcortical structures with thalamic nuclei playing a particularly important role. It has been proposed that the failure to disambiguate self-induced from externally generated sensory input may cause some of the positive symptoms in schizophrenia such as auditory hallucinations and delusions of passivity. Here, we review the current data on the role of efference copy signals within different sensory modalities as well as the behavioral, structural and functional abnormalities in clinical groups that support this hypothesis.


Assuntos
Atenção/fisiologia , Alucinações/fisiopatologia , Reconhecimento Visual de Modelos , Esquizofrenia/fisiopatologia , Alucinações/etiologia , Humanos , Esquizofrenia/complicações , Tálamo/fisiopatologia
20.
J Vis Exp ; (64)2012 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-22759999

RESUMO

The aim of this methods paper is to describe how to implement a neuroimaging technique to examine complementary brain processes engaged by two similar tasks. Participants' behavior during task performance in an fMRI scanner can then be correlated to the brain activity using the blood-oxygen-level-dependent signal. We measure behavior to be able to sort correct trials, where the subject performed the task correctly and then be able to examine the brain signals related to correct performance. Conversely, if subjects do not perform the task correctly, and these trials are included in the same analysis with the correct trials we would introduce trials that were not only for correct performance. Thus, in many cases these errors can be used themselves to then correlate brain activity to them. We describe two complementary tasks that are used in our lab to examine the brain during suppression of an automatic responses: the stroop(1) and anti-saccade tasks. The emotional stroop paradigm instructs participants to either report the superimposed emotional 'word' across the affective faces or the facial 'expressions' of the face stimuli(1,2). When the word and the facial expression refer to different emotions, a conflict between what must be said and what is automatically read occurs. The participant has to resolve the conflict between two simultaneously competing processes of word reading and facial expression. Our urge to read out a word leads to strong 'stimulus-response (SR)' associations; hence inhibiting these strong SR's is difficult and participants are prone to making errors. Overcoming this conflict and directing attention away from the face or the word requires the subject to inhibit bottom up processes which typically directs attention to the more salient stimulus. Similarly, in the anti-saccade task(3,4,5,6), where an instruction cue is used to direct only attention to a peripheral stimulus location but then the eye movement is made to the mirror opposite position. Yet again we measure behavior by recording the eye movements of participants which allows for the sorting of the behavioral responses into correct and error trials(7) which then can be correlated to brain activity. Neuroimaging now allows researchers to measure different behaviors of correct and error trials that are indicative of different cognitive processes and pinpoint the different neural networks involved.


Assuntos
Cognição/fisiologia , Imageamento por Ressonância Magnética/métodos , Córtex Pré-Frontal/fisiologia , Análise e Desempenho de Tarefas , Emoções , Expressão Facial , Humanos
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