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Frontiers in Neuroscience 2018Familiarity in music has been reported as an important factor modulating emotional and hedonic responses in the brain. Familiarity and repetition may increase the liking...
Familiarity in music has been reported as an important factor modulating emotional and hedonic responses in the brain. Familiarity and repetition may increase the liking of a piece of music, thus inducing positive emotions. Neuroimaging studies have focused on identifying the brain regions involved in the processing of familiar and unfamiliar musical stimuli. However, the use of different modalities and experimental designs has led to discrepant results and it is not clear which areas of the brain are most reliably engaged when listening to familiar and unfamiliar musical excerpts. In the present study, we conducted a systematic review from three databases (Medline, PsychoINFO, and Embase) using the keywords (recognition OR familiar OR familiarity OR exposure effect OR repetition) AND (music OR song) AND (brain OR brains OR neuroimaging OR functional Magnetic Resonance Imaging OR Position Emission Tomography OR Electroencephalography OR Event Related Potential OR Magnetoencephalography). Of the 704 titles identified, 23 neuroimaging studies met our inclusion criteria for the systematic review. After removing studies providing insufficient information or contrasts, 11 studies (involving 212 participants) qualified for the meta-analysis using the activation likelihood estimation (ALE) approach. Our results did not find significant peak activations consistently across included studies. Using a less conservative approach ( < 0.001, uncorrected for multiple comparisons) we found that the left superior frontal gyrus, the ventral lateral (VL) nucleus of the left thalamus, and the left medial surface of the superior frontal gyrus had the highest likelihood of being activated by familiar music. On the other hand, the left insula, and the right anterior cingulate cortex had the highest likelihood of being activated by unfamiliar music. We had expected limbic structures as top clusters when listening to familiar music. But, instead, music familiarity had a motor pattern of activation. This could reflect an audio-motor synchronization to the rhythm which is more engaging for familiar tunes, and/or a sing-along response in one's mind, anticipating melodic, harmonic progressions, rhythms, timbres, and lyric events in the familiar songs. These data provide evidence for the need for larger neuroimaging studies to understand the neural correlates of music familiarity.
PubMed: 30344470
DOI: 10.3389/fnins.2018.00686 -
Neurosurgical Focus Sep 2018OBJECTIVE Despite perioperative risks, epilepsy surgery represents a legitimate curative or palliative treatment approach for children with drug-resistant epilepsy... (Meta-Analysis)
Meta-Analysis
OBJECTIVE Despite perioperative risks, epilepsy surgery represents a legitimate curative or palliative treatment approach for children with drug-resistant epilepsy (DRE). Several factors characterizing infants and toddlers with DRE create unique challenges regarding optimal evaluation and management. Epilepsy surgery within children < 3 years of age has received moderate attention in the literature, including mainly case series and retrospective studies. This article presents a systematic literature review and explores multidisciplinary considerations for the preoperative evaluation and surgical management of infants and toddlers with DRE. METHODS The study team conducted a systematic literature review based on Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, targeting studies that investigated children < 3 years of age undergoing surgical treatment of DRE. Using the PubMed database, investigators selected peer-reviewed articles that reported seizure outcomes with or without developmental outcomes and/or perioperative complications. Studies were eliminated based on the following exclusion criteria: sample size < 5 patients; and inclusion of patients > 3 years of age, when demographic and outcomes data could not be separated from the cohort of patients < 3 years of age. RESULTS The study team identified 20 studies published between January 1990 and May 2017 that satisfied eligibility criteria. All selected studies represented retrospective reviews, observational studies, and uncontrolled case series. The compiled group of studies incorporated 465 patients who underwent resective or disconnective surgery (18 studies, 444 patients) or vagus nerve stimulator insertion (2 studies, 21 patients). Patient age at surgery ranged between 28 days and 36 months, with a mean of 16.8 months (1.4 years). DISCUSSION The study team provided a detailed summary of the literature review, focusing on the etiologies, preoperative evaluation, surgical treatments, seizure and developmental outcomes, and potential for functional recovery of infants and toddlers with DRE. Additionally, the authors discussed special considerations in this vulnerable age group from the perspective of multiple disciplines. CONCLUSIONS While presenting notable challenges, pediatric epilepsy surgery within infants and toddlers (children < 3 years of age) offers significant opportunities for improved seizure frequency, neuro-cognitive development, and quality of life. Successful evaluation and treatment of young children with DRE requires special consideration of multiple aspects related to neurological and physiological immaturity and surgical morbidity.
Topics: Child, Preschool; Disease Management; Drug Resistant Epilepsy; Electroencephalography; Humans; Infant; Neurosurgical Procedures; Observational Studies as Topic; Preoperative Care; Retrospective Studies; Treatment Outcome
PubMed: 30173613
DOI: 10.3171/2018.7.FOCUS18220 -
Journal of Affective Disorders Dec 2018Maternal anxiety disorders are common during pregnancy and postpartum, and are associated with increased behaviour problems and risk of mental health difficulties in...
BACKGROUND
Maternal anxiety disorders are common during pregnancy and postpartum, and are associated with increased behaviour problems and risk of mental health difficulties in children. Understanding alterations in brain structure and function associated with maternal anxiety may help elucidate potential mechanisms via which high maternal anxiety could affect children.
METHODS
We conducted a systematic review of extant research studying the associations between prenatal anxiety and children's brain structure and function, as assessed through neuroimaging. Data were gathered in accordance with the PRISMA review guidelines.
RESULTS
Ten articles were identified, and all found a significant association between antenatal maternal anxiety and child neurodevelopment. Studies vary considerably in their methods with five studies employing electroencephalography (EEG), one using magnetoencephalography (MEG), and the rest employing magnetic resonance imaging (MRI).
LIMITATIONS
The heterogeneity of neuroimaging techniques undertaken by the reviewed studies precluded a meta-analysis from being performed. The applicability of this systematic review to clinical practice is also limited given that the studies examined children across a wide age range (neonates to 17 years).
CONCLUSIONS
From early infancy to late adolescence, findings suggest alterations of brain structure and function in frontal, temporal, and limbic areas in children born to mothers who experienced prenatal anxiety. These brain abnormalities may underlie associations between prenatal anxiety and children's behaviour, though more research incorporating neuroimaging and behavioural data is necessary to determine this.
Topics: Anxiety Disorders; Brain; Child; Child Development; Electroencephalography; Female; Humans; Magnetic Resonance Imaging; Mothers; Neuroimaging; Pregnancy; Pregnancy Complications
PubMed: 30118945
DOI: 10.1016/j.jad.2018.08.029 -
Journal of Neuroscience Methods Jan 2019Predicting sensorimotor upper limb outcome receives continued attention in stroke. Neurophysiological measures by electroencephalography (EEG) and magnetoencephalography...
A systematic review investigating the relationship of electroencephalography and magnetoencephalography measurements with sensorimotor upper limb impairments after stroke.
BACKGROUND
Predicting sensorimotor upper limb outcome receives continued attention in stroke. Neurophysiological measures by electroencephalography (EEG) and magnetoencephalography (MEG) could increase the accuracy of predicting sensorimotor upper limb recovery.
NEW METHOD
The aim of this systematic review was to summarize the current evidence for EEG/MEG-based measures to index neural activity after stroke and the relationship between abnormal neural activity and sensorimotor upper limb impairment. Relevant papers from databases EMBASE, CINHAL, MEDLINE and pubMED were identified. Methodological quality of selected studies was assessed with the Modified Downs and Black form. Data collected was reported descriptively.
RESULTS
Seventeen papers were included; 13 used EEG and 4 used MEG applications. Findings showed that: (a) the presence of somatosensory evoked potentials in the acute stage are related to better outcome of upper limb motor impairment from 10 weeks to 6 months post-stroke; (b) an interhemispheric imbalance of cortical oscillatory signals associated with upper limb impairment; and (c) predictive models including beta oscillatory cortical signal factors with corticospinal integrity and clinical measures could enhance upper limb motor prognosis.
COMPARING WITH EXISTING METHOD
The combination of neurological biomarkers with clinical measures results in higher statistical power than using neurological biomarkers alone when predicting motor recovery in stroke.
CONCLUSIONS
Alterations in neural activity by means of EEG and MEG are demonstrated from the early post-stroke stage onwards, and related to sensorimotor upper limb impairment. Future work exploring cortical oscillatory signals in the acute stage could provide further insight about prediction of upper limb sensorimotor recovery.
Topics: Brain; Brain Waves; Electroencephalography; Evoked Potentials, Somatosensory; Humans; Magnetoencephalography; Stroke; Upper Extremity
PubMed: 30118725
DOI: 10.1016/j.jneumeth.2018.08.009 -
Explore (New York, N.Y.) 2018Across cultures and throughout history, transcendent states achieved through meditative practices have been reported. The practices to attain transcendent states vary... (Review)
Review
BACKGROUND
Across cultures and throughout history, transcendent states achieved through meditative practices have been reported. The practices to attain transcendent states vary from transcendental meditation to yoga to contemplative prayer, to other various forms of sitting meditation. While these transcendent states are ascribed many different terms, those who experience them describe a similar unitive, ineffable state of consciousness. Despite the common description, few studies have systematically examined transcendent states during meditation.
OBJECTIVES
The objectives of this systematic review were to: 1) characterize studies evaluating transcendent states associated with meditation in any tradition; 2) qualitatively describe physiological and phenomenological outcomes collected during transcendent states and; 3) evaluate the quality of these studies using the Quality Assessment Tool.
METHODS
Medline, PsycINFO, CINAHL, AltHealthWatch, AMED, and the Institute of Noetic Science Meditation Library were searched for relevant papers in any language. Included studies required adult participants and the collection of outcomes before, during, or after a reported transcendent state associated with meditation.
RESULTS
Twenty-five studies with a total of 672 combined participants were included in the final review. Participants were mostly male (61%; average age 39 ± 11 years) with 12.7 ± 6.6 (median 12.6; range 2-40) average years of meditation practice. A variety of meditation traditions were represented: (Buddhist; Christian; Mixed (practitioners from multiple traditions); Vedic: Transcendental Meditation and Yoga). The mean quality score was 67 ± 13 (100 highest score possible). Subjective phenomenology and the objective outcomes of electroencephalography (EEG), electrocardiography, electromyography, electrooculogram, event-related potentials, functional magnetic resonance imaging, magnetoencephalography, respiration, and skin conductance and response were measured. Transcendent states were most consistently associated with slowed breathing, respiratory suspension, reduced muscle activity and EEG alpha blocking with external stimuli, and increased EEG alpha power, EEG coherence, and functional neural connectivity. The transcendent state is described as being in a state of relaxed wakefulness in a phenomenologically different space-time. Heterogeneity between studies precluded any formal meta-analysis and thus, conclusions about outcomes are qualitative and preliminary.
CONCLUSIONS
Future research is warranted into transcendent states during meditation using more refined phenomenological tools and consistent methods and outcome evaluation.
Topics: Adult; Consciousness; Female; Humans; Male; Meditation; Middle Aged; Religion and Psychology; Yoga
PubMed: 29269049
DOI: 10.1016/j.explore.2017.07.007 -
Clinical Neurophysiology : Official... Sep 2017Neuroimaging studies provide evidence of disturbed resting-state brain networks in Schizophrenia (SZ). However, untangling the neuronal mechanisms that subserve these... (Review)
Review
OBJECTIVE
Neuroimaging studies provide evidence of disturbed resting-state brain networks in Schizophrenia (SZ). However, untangling the neuronal mechanisms that subserve these baseline alterations requires measurement of their electrophysiological underpinnings. This systematic review specifically investigates the contributions of resting-state Magnetoencephalography (MEG) in elucidating abnormal neural organization in SZ patients.
METHOD
A systematic literature review of resting-state MEG studies in SZ was conducted. This literature is discussed in relation to findings from resting-state fMRI and EEG, as well as to task-based MEG research in SZ population. Importantly, methodological limitations are considered and recommendations to overcome current limitations are proposed.
RESULTS
Resting-state MEG literature in SZ points towards altered local and long-range oscillatory network dynamics in various frequency bands. Critical methodological challenges with respect to experiment design, and data collection and analysis need to be taken into consideration.
CONCLUSION
Spontaneous MEG data show that local and global neural organization is altered in SZ patients. MEG is a highly promising tool to fill in knowledge gaps about the neurophysiology of SZ. However, to reach its fullest potential, basic methodological challenges need to be overcome.
SIGNIFICANCE
MEG-based resting-state power and connectivity findings could be great assets to clinical and translational research in psychiatry, and SZ in particular.
Topics: Brain; Brain Mapping; Humans; Magnetic Resonance Imaging; Magnetoencephalography; Nerve Net; Rest; Schizophrenia
PubMed: 28756348
DOI: 10.1016/j.clinph.2017.06.246 -
Neuroscience and Biobehavioral Reviews Sep 2017Our objective was to identify the physiological measures that are sensitive to assessing cognitive workload across the spectrum of cognitive impairments. Three database... (Review)
Review
Our objective was to identify the physiological measures that are sensitive to assessing cognitive workload across the spectrum of cognitive impairments. Three database searches were conducted: PubMed, PsychINFO, and Web of Science. Studies from the last decade that used physiological measures of cognitive workload in older adults (mean age >65 years-old) were reviewed. The cognitive workload of healthy older individuals was compared with the cognitive workload of younger adults, patients with mild cognitive impairment (MCI), and patients with Alzheimer's diseases (AD). The most common measures of cognitive workload included: electroencephalography, magnetoencephalography, functional magnetic resonance imaging, pupillometry, and heart rate variability. These physiological measures consistently showed greater cognitive workload in healthy older adults compared to younger adults when performing the same task. The same was observed in patients with MCI compared to healthy older adults. Behavioral performance declined when the available cognitive resources became insufficient to cope with the cognitive demands of a task, such as in AD. These findings may have implications for clinical practice and future cognitive interventions.
Topics: Aging; Brain; Cognition; Cognitive Dysfunction; Humans
PubMed: 28711663
DOI: 10.1016/j.neubiorev.2017.07.001 -
PloS One 2017Although it is well recognized that autism is associated with altered patterns of over- and under-connectivity, specifics are still a matter of debate. Little has been... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Although it is well recognized that autism is associated with altered patterns of over- and under-connectivity, specifics are still a matter of debate. Little has been done so far to synthesize available literature using whole-brain electroencephalography (EEG) and magnetoencephalography (MEG) recordings.
OBJECTIVES
1) To systematically review the literature on EEG/MEG functional and effective connectivity in autism spectrum disorder (ASD), 2) to synthesize and critically appraise findings related with the hypothesis that ASD is characterized by long-range underconnectivity and local overconnectivity, and 3) to provide, based on the literature, an analysis of tentative factors that are likely to mediate association between ASD and atypical connectivity (e.g., development, topography, lateralization).
METHODS
Literature reviews were done using PubMed and PsychInfo databases. Abstracts were screened, and only relevant articles were analyzed based on the objectives of this paper. Special attention was paid to the methodological characteristics that could have created variability in outcomes reported between studies.
RESULTS
Our synthesis provides relatively strong support for long-range underconnectivity in ASD, whereas the status of local connectivity remains unclear. This observation was also mirrored by a similar relationship with lower frequencies being often associated with underconnectivity and higher frequencies being associated with both under- and over-connectivity. Putting together these observations, we propose that ASD is characterized by a general trend toward an under-expression of lower-band wide-spread integrative processes compensated by more focal, higher-frequency, locally specialized, and segregated processes. Further investigation is, however, needed to corroborate the conclusion and its generalizability across different tasks. Of note, abnormal lateralization in ASD, specifically an elevated left-over-right EEG and MEG functional connectivity ratio, has been also reported consistently across studies.
CONCLUSIONS
The large variability in study samples and methodology makes a systematic quantitative analysis (i.e. meta-analysis) of this body of research impossible. Nevertheless, a general trend supporting the hypothesis of long-range functional underconnectivity can be observed. Further research is necessary to more confidently determine the status of the hypothesis of short-range overconnectivity. Frequency-band specific patterns and their relationships with known symptoms of autism also need to be further clarified.
Topics: Autistic Disorder; Connectome; Electroencephalography; Humans; Magnetoencephalography
PubMed: 28467487
DOI: 10.1371/journal.pone.0175870 -
Clinical Neurophysiology : Official... Jun 2017The Human Immunodeficiency Virus (HIV) has an impact on the brain, even when the infection is well-controlled with modern highly-active antiretroviral therapy (HAART).... (Meta-Analysis)
Meta-Analysis
OBJECTIVE
The Human Immunodeficiency Virus (HIV) has an impact on the brain, even when the infection is well-controlled with modern highly-active antiretroviral therapy (HAART). While dementia is rare in those on HAART, milder cognitive impairment is common. The causes, patterns, and evolution of brain dysfunction in people living with HIV remain uncertain. We evaluate whether electrophysiological methods provide informative measures of brain dysfunction in this population.
METHODS
A systematic literature search identified studies that used EEG or MEG to evaluate persons living with HIV published between 1996 (when HAART became available) and 2016.
RESULTS
Twenty-eight studies were identified. Most involved small samples, and all but four were cross-sectional. Reduced amplitude of Event Related Potentials and decreased power in the alpha band at rest were the most frequent differences between people with and without HIV infection. Of the 16 studies that also assessed cognitive ability, 13 found a significant relationship between cognition and electrophysiological changes in the HIV+ groups. Five of those studies also reported a significant relationship with current immunosuppression, suggesting a direct effect of HIV on the brain. There were few longitudinal studies; whether these electrophysiological changes progress over time, or respond to treatment, remains unclear.
CONCLUSIONS
EEG and MEG can provide useful information about brain dysfunction in people with HIV infection, but more consistent assessments of both cognition and EEG patterns, as well as longitudinal studies with larger, better characterized samples are needed.
SIGNIFICANCE
This is the first systematic review of electrophysiological findings in HIV since the availability of HAART. EEG and MEG measures are sensitive to brain dysfunction in this population, and could complement other approaches in improving the assessment, understanding and treatment of neurocognitive disorders in HIV.
Topics: AIDS Dementia Complex; Acquired Immunodeficiency Syndrome; Antiretroviral Therapy, Highly Active; Brain; Electroencephalography; Evoked Potentials; Humans; Magnetoencephalography
PubMed: 28433855
DOI: 10.1016/j.clinph.2017.03.035 -
JBI Database of Systematic Reviews and... Dec 2016After stroke, regaining functional use of the upper limb can be challenging. Temporary deafferentation (TD) is a novel approach used in neurorehabilitation to...
BACKGROUND
After stroke, regaining functional use of the upper limb can be challenging. Temporary deafferentation (TD) is a novel approach used in neurorehabilitation to voluntarily reduce the somatosensory input in a body part by temporary anesthesia; which has been shown to improve sensorimotor functions in the affected limb.
OBJECTIVES
The primary objective of this systematic review was to present the best available evidence related to the effects of TD of the affected arm on the recovery of motor function and activity of the upper limb (arm and hand) following stroke. Further, this review aimed to assess the effects of TD on sensory function, activities of daily living (ADL) and quality of life following stroke, the acceptability and safety of the intervention as well as adverse events.
INCLUSION CRITERIA TYPES OF PARTICIPANTS
Adult patients (18 years and older) with a clinical diagnosis of stroke, either hemorrhagic or ischemic.
TYPES OF INTERVENTIONS
Reports of rehabilitation that included the use of a pneumatic tourniquet, regional anesthesia or nerve block to achieve TD of an arm, or the use of TD as a stand-alone intervention.
OUTCOMES
Primary outcomes were motor function and activity of the upper limb using assessment scales, motor tests and global motor functions.Secondary outcomes included measures of sensory function, ADL, impact of stroke and quality of life and pain.Additional outcomes were neurophysiological changes as studied with functional magnetic resonance imaging, magnetoencephalography and/or transcranial magnetic stimulation.Acceptability and safety of the intervention as well as adverse events were also included.
TYPES OF STUDIES
We included any experimental and epidemiological studies. There were no randomized controlled trials. We included non-randomized controlled trials, quasi-experimental, before and after studies and case-control studies.
SEARCH STRATEGY
We searched for both published and unpublished studies in major databases and all reference lists of relevant articles in English, German or French languages. We included studies published from January 1980 to October 2015.
DATA EXTRACTION
Data were extracted from included studies using a standardized data extraction tool from the Joanna Briggs Institute.
DATA SYNTHESIS
There was heterogeneity in the types of intervention and outcome measures, therefore statistical pooling of the findings was not appropriate. As such, the studies were grouped according to type of outcome where possible. Findings are presented in a narrative form.
RESULTS
Eight studies met the eligibility criteria. All outcome parameters related to the primary outcome (motor function and activity of the more affected upper extremity) showed an improvement during or after TD. The sensory functions significantly improved during or after TD when measured either by the grating orienting task or the grating orientation accuracy, and slightly improved when measured using the von Frey hair testing during TD.
CONCLUSION
There is evidence supporting the use of TD of the upper extremity in adults after stroke. Temporary deafferentation can be recommended (Grade B).
PubMed: 28009677
DOI: 10.11124/JBISRIR-2016-003231