Synchronised neuronal oscillations at beta frequencies are prevalent in the human motor system, but their function is unclear. In this Opinion article, we propose that the levels of beta oscillations provide a measure of the likelihood that a new voluntary action will need to be actuated. Oscillatory beta activity is in turn modulated by net dopamine levels at sites of cortical input to the basal ganglia. We hypothesise that net dopamine levels are modulated in response to salient internal and external cues. Crucially, the resulting modulation of beta activity is predictive, enabling the appropriate prospective resourcing and preparation of potential actions. Loss of dopamine, as in Parkinson's disease, annuls this function, unless net dopaminergic activity can be elevated through medication.
Source & Read More: https://www.cell.com
Double-blind, randomized pilot clinical trial targeting alpha oscillations for the treatment of major depressive disorder (MDD)”
“Double-blind, randomized pilot clinical trial targeting alpha oscillations with transcranial alternating current stimulation (tACS) for the treatment of major depressive disorder (MDD)”
Morgan L. Alexander, Sankaraleengam Alagapan, Courtney E. Lugo, Juliann M. Mellin, Caroline Lustenberger, David R. Rubinow & Flavio Fröhlich in Translational Psychiatry volume 9, Article number: 106 (2019) |
Double-blind, randomized pilot clinical trial targeting alpha oscillations with transcranial alternating current stimulation (tACS) for the treatment of major depressive disorder (MDD)
A comparative study of axis I antecedents before age 18 of unipolar depression, bipolar disorder and schizophrenia.
Despite a large scientific literature on early clinical precursors of schizophrenia, bipolar disorder and unipolar depression, few data are available on axis I disorders preceding the adult onset of these illnesses.
SAMPLING AND METHODS:
Disorders before the age of 18 years were retrospectively assessed with a structured interview in 3 groups of consecutive adult inpatients with DSM-IV diagnoses of schizophrenia (n = 197), major depressive disorder (n = 287) and bipolar disorder (n = 132). Only patients with adult onset of schizophrenia and of mania/hypomania were included. A sample of the general population served as control group (n = 300).
RESULTS AND CONCLUSION:
The clinical groups significantly outnumbered the control sample on the majority of early axis I diagnoses. Schizophrenia was significantly associated (1) with attention deficit hyperactivity disorder (ADHD), ADHD inattentive subtype, ADHD hyperactive subtype and primary nocturnal enuresis, compared to unipolar depression, and (2) with social phobia and ADHD inattentive subtype, compared to bipolar disorder. Oppositional defiant disorder was significantly associated with bipolar disorder, compared to the other clinical and control groups. The ADHD hyperactive subtype predicted the adult onset of bipolar disorder compared to unipolar depression. Externalizing disorders seem of special importance as regards the clinical pathways toward schizophrenia.
Source & Read More: https://www.ncbi.nlm.nih.gov
Risk of bipolar disorder and schizophrenia in relatives of people with attention-deficit hyperactivity disorder.
Attention-deficit hyperactivity disorder (ADHD) is associated with bipolar disorder and schizophrenia, and it has been suggested that combined bipolar disorder and ADHD is aetiologically distinct from the pure disorders.
AIMS:To clarify whether ADHD shares genetic and environmental factors with bipolar disorder and schizophrenia.
By linking longitudinal Swedish national registers, we identified 61 187 persons with ADHD (the proband group) and their first- and second-degree relatives, and matched them with a control group of people without ADHD and their corresponding relatives. Conditional logistic regression was used to determine the risks of bipolar disorder and schizophrenia in the relatives of the two groups.
First-degree relatives of the ADHD proband group were at increased risk of both bipolar disorder (odds ratio (OR) = 1.84-2.54 for parents, offspring and full siblings) and schizophrenia (OR = 1.71-2.22 for parents, offspring and full siblings). The risks of bipolar disorder and schizophrenia among second-degree relatives were substantially lower than among full siblings.
These findings suggest that the co-occurrence of ADHD and bipolar disorder as well as ADHD and schizophrenia is due to shared genetic factors, rather than representing completely aetiologically distinct subsyndromes.
Source & Read More: https://www.ncbi.nlm.nih.gov
Association between Attention-Deficit Hyperactivity Disorder in childhood and schizophrenia later in adulthood.
To estimate the risk of schizophrenia in adulthood among children and adolescents with ADHD compared to the background population.
SUBJECTS/MATERIALS AND METHODS:
Two hundred and eight youths with ADHD (183 boys; 25 girls) were followed prospectively. Diagnoses of schizophrenia were obtained from The Danish Psychiatric Central Register. The relative risk (RR) of schizophrenia for cases with ADHD, compared to the normal population, was calculated as risk ratios. Hazard ratios (HR's) by Cox regression were calculated in the predictor analyses.
Mean age for ADHD cases at follow-up was 31.1years. Schizophrenia diagnoses were given to 3.8% of these cases. Compared to the general population, RR of schizophrenia in cases with ADHD was 4.3 (95% CI 1.9-8.57).
DISCUSSION AND CONCLUSION:
This prospective follow-up study found children with ADHD to be at higher risk of later schizophrenia than controls. If replicated, these results warrant increased focus on the possible emergence symptoms of schizophrenia or schizophreniform psychosis during clinical follow-up of patients with ADHD.
Source & Read more: https://www.ncbi.nlm.nih.gov
Zapping Memories: Electrostimulation Restores Working Memory of 70 Year Olds’ to That of 20 Year Olds’
Summary: Non-invasive electrostimulation restores working memory in 70-year-olds, allowing for comparable to cognitive abilities to those of 20-year-olds. The technology increases neural synchronization patterns and information flow between frontotemporal regions of the brain. This results in rapid improvements of working memory in older people, which lasted for more than 50 minutes post stimulation. The findings offer new hope to those suffering age-related memory impairments.
Source: Boston University
Brain stimulation techniques can modulate cognitive functions in many neuropsychiatric diseases. Pilot studies have shown promising effects of brain stimulations on Alzheimer's disease (AD). Brain stimulations can be categorized into non-invasive brain stimulation (NIBS) and invasive brain stimulation (IBS). IBS includes deep brain stimulation (DBS), and invasive vagus nerve stimulation (VNS), whereas NIBS includes transcranial magnetic stimulation (TMS), transcranial direct current stimulation (tDCS), transcranial alternating current stimulation (tACS), electroconvulsive treatment (ECT), magnetic seizure therapy (MST), cranial electrostimulation (CES), and non-invasive VNS. We reviewed the cutting-edge research on these brain stimulation techniques and discussed their therapeutic effects on AD. Both IBS and NIBS may have potential to be developed as novel treatments for AD; however, mixed findings may result from different study designs, patients selection, population, or samples sizes. Therefore, the efficacy of NIBS and IBS in AD remains uncertain, and needs to be further investigated. Moreover, more standardized study designs with larger sample sizes and longitudinal follow-up are warranted for establishing a structural guide for future studies and clinical application.
Keywords: brain stimulation, Alzheimer's disease (AD), transcranial magnetic stimulation (TMS), transcranial direct current stimulation (tDCS), transcranial alternating current stimulation (tACS), electroconvulsive treatment (ECT), magnetic seizure therapy (MST), cranial electrostimulation (CES)
Electrophysiological Neuroimaging using sLORETA Comparing 100 Schizophrenia Patients to 48 Patients with Major Depression
In this retrospective analysis of electroencephalograms were to identify a surrogate biomarker for the Dopamine D2 receptors in the brain by comparing patients diagnosed with Schizophrenia taking Atypical Antipsychotics to Depressive patients medicated with Selective Serotonin Reuptake Inhibitors. To achieve this, thirty-seconds of resting EEG were spectrally transformed in sLORETA. Three-dimensional statistical non-paramentric maps (SnPM) for the sLORETA Global Field Power within each band were then computed. Our results illustrated that the Right Superior Frontal Gyrus (t=2.049, p=0.007), along the dopamine mesolimbic pathway, had higher neuronal oscillations in the delta frequency band in the 100 Schizophrenia patients as compared to the 32-depressive female patients. The comparisons with both the 48 depressive patient cohort or the sixteen male depressive patient cohort did not yield any statistically significant findings. We conclude that the Superior Frontal Gyrus should be investigated as a possible surrogate biomarker for preclinical and clinical drug discovery in neuropharmacology.
Keywords: Dopamine Receptors, Schizophrenia, sLORETA, Mesolimbic
This report provides practical information regarding the use of EEG biofeedback ("neurofeedback") for a variety of uses. It will survey some ofthe major issues, approaches and methods that are currently in use, and describe their overall benefits and limitations. This should help the user or practitioner to evaluate and select neurofeedback instruments, and to put them to use for the needs at hand.
Neurofeedback is a kind of biofeedback, which teaches self-control of brain functions to subjects by measuring brain waves and providing a feedback signal. Neurofeedback usually provides the audio and or video feedback. Positive or negative feedback is produced for desirable or undesirable brain activities, respectively. In this review, we provided clinical and technical information about the following issues: (1) Various neurofeedback treatment protocols i.e. alpha, beta, alpha/theta, delta, gamma, and theta; (2) Different EEG electrode placements i.e. standard recording channels in the frontal, temporal, central, and occipital lobes; (3) Electrode montages (unipolar, bipolar); (4) Types of neurofeedback i.e. frequency, power, slow cortical potential, functional magnetic resonance imaging, and so on; (5) Clinical applications of neurofeedback i.e. treatment of attention deficit hyperactivity disorder, anxiety, depression, epilepsy, insomnia, drug addiction, schizophrenia, learning disabilities, dyslexia and dyscalculia, autistic spectrum disorders and so on as well as other applications such as pain management, and the improvement of musical and athletic performance; and (6) Neurofeedback softwares. To date, many studies have been conducted on the neurofeedback therapy and its effectiveness on the treatment of many diseases. Neurofeedback, like other treatments, has its own pros and cons. Although it is a non-invasive procedure, its validity has been questioned in terms of conclusive scientific evidence. For example, it is expensive, time-consuming and its benefits are not long-lasting. Also, it might take months to show the desired improvements. Nevertheless, neurofeedback is known as a complementary and alternative treatment of many brain dysfunctions. However, current research does not support conclusive results about its efficacy.
Keywords: Brain diseases, Brain waves, Complementary therapies, Electroencephalography, Neurofeedback
Abnormal low-gamma activity, hypothesized to reflect impaired synchronization, has been evidenced in several brain disorders
Neural oscillations in the low-gamma range (30–50 Hz) have been implicated in neuronal synchrony, computation, behavior, and cognition. Abnormal low-gamma activity, hypothesized to reflect impaired synchronization, has been evidenced in several brain disorders. Thus, understanding the relations between gamma oscillations, neuronal synchrony and behavior is a major research challenge. We used a brain-machine interface (BMI) to train monkeys to specifically increase low-gamma power in selected sites of motor cortex to move a cursor and obtain a reward. The monkeys learned to robustly generate oscillatory gamma waves, which were accompanied by a dramatic increase of spiking synchrony of highly precise spatiotemporal patterns. The findings link volitional control of LFP oscillations, neuronal synchrony, and the behavioral outcome. Subjects’ ability to directly modulate specific patterns of neuronal synchrony provides a powerful approach for understanding neuronal processing in relation to behavior and for the use of BMIs in a clinical setting.
The term “brain (or neural) oscillations” refers to the rhythmic and/or repetitive electrical activity generated spontaneously and in response to stimuli by neural tissue in the central nervous system. The importance of brain oscillations in sensory-cognitive processes has become increasingly evident. It has also become clear that event-related oscillations are modified in many types of neuropathology, in particular in cognitive impairment. This review discusses methods such as evoked/event-related oscillations and spectra, coherence analysis, and phase locking. It gives examples of applications of essential methods and concepts in bipolar disorder that provide a basis for fundamental notions regarding neurophysiologic biomarkers in cognitive impairment. The take-home message is that in the development of diagnostic and pharmacotherapeutic strategies, neurophysiologic data should be analyzed in a framework that uses a multiplicity of methods and frequency bands.
Keywords: oscillation, bipolar disorder, schizophrenia, alpha, beta, gamma, theta, delta, phase synchrony
Summary: Memory performance can be enhanced by rhythmic neural stimulation, using both invasive and non-invasive techniques.
Source: University of Birmingham
Controlling the frequency of ‘brain waves’ could help to improve people’s recall of memories and potentially provide a key to unlock conditions such as Alzheimer’s disease, according to a new article.
Brain oscillations occur during neural processes that are relevant for memory and using different approaches to drive these brain waves demonstrates a direct link to improving memory.
Neuroscientists at the University of Birmingham have reviewed research in the field and conclude that memory performance can be improved by rhythmic neural stimulation or ‘entrainment’ – using a range of invasive and non-invasive techniques.
Working with partners at Ruhr University Bochum, in Germany and Emory University Hospital, Atlanta, USA, they published their findings in a review article for the journal Trends in Neurosciences.
Dr Simon Hanslmayr, from the University of Birmingham’s Centre for Human Brain Health, commented: “We can modulate memory performance via rhythmic neural stimulation, which can be as simple as flickering light at a particular rhythm which then is followed by neurons in the brain.
“Much more research will be required, but it seems clear that driving brain rhythms in such a way is a promising tool for improving memory – both for healthy people and for patients suffering from conditions such as Alzheimer’s disease.”
Summary: Reduced connectivity between the amygdala and ventrolateral prefrontal cortex has been identified in children on the autism spectrum who exhibit disruptive behaviors, compared to those on the spectrum who do not. Findings suggest this distinct brain network could be independent of core autism symptoms.
Authors: Martijn Arns, Ilse Feddema and J. Leon Kenemans
Recent studies suggest a role for sleep and sleep problems in the etiology of attention deficit hyperactivity disorder (ADHD) and a recent model about the working mechanism of sensori-motor rhythm (SMR) neurofeedback, proposed that this intervention normalizes sleep and thus improves ADHD symptoms such as inattention and hyperactivity/impulsivity.