Suppression Of Beta Research Articles

Cardiac cycle modulates alpha and beta suppression during motor imagery.

Previous interoception research has demonstrated that sensory processing is reduced during cardiac systole, an effect associated with diminished cortical excitability, possibly due to heightened baroreceptor activity. This study aims to determine how phases of the cardiac cycle-systole and diastole-modulate neural sensorimotor activity during motor imagery (MI) and motor execution (ME). We hypothesised that MI performance, indexed by enhanced suppression of contralateral sensorimotor alpha (8-13Hz) and beta (14-30Hz) activity, would be modulated by the cardiac phases, with improved performance during diastole due to enhanced sensory processing of movement cues. Additionally, we investigated whether movement cues during systole or diastole enhance muscle activity. To test these hypotheses, 29 participants were instructed to perform or imagine thumb abductions, while we recorded their electroencephalography, electrocardiogram, and electromyogram (EMG) activity. We show that imaginary movements instructed during diastole lead to more pronounced suppression of alpha and beta activity in contralateral sensorimotor cortices, with no significant cardiac timing effects observed during ME as confirmed by circular statistics. Additionally, diastole was associated with significantly increased EMG on the side of actual and, to a lesser degree, imagined movements. Our study identifies optimal cardiac phases for MI performance, suggesting potential pathways to enhance MI-based assistive technologies.

Selective suppression of oligodendrocyte-derived amyloid beta rescues neuronal dysfunction in Alzheimer's disease.

Reduction of amyloid beta (Aβ) has been shown to be effective in treating Alzheimer's disease (AD), but the underlying assumption that neurons are the main source of pathogenic Aβ is untested. Here, we challenge this prevailing belief by demonstrating that oligodendrocytes are an important source of Aβ in the human brain and play a key role in promoting abnormal neuronal hyperactivity in an AD knock-in mouse model. We show that selectively suppressing oligodendrocyte Aβ production improves AD brain pathology and restores neuronal function in the mouse model in vivo. Our findings suggest that targeting oligodendrocyte Aβ production could be a promising therapeutic strategy for treating AD.

Evaluation of Serum Vitamin D and IL-1ß in Patients with Oral Lichen Planus and Healthy Subjects: A Research Protocol

Introduction: Oral Lichen Planus (OLP) is a chronic mucocutaneous immune-mediated disease that has been classified as a Potentially Malignant Disorder (PMD). The aetiology of OLP needs further exploration. Research indicates that the immune system plays a pivotal role in the progression of OLP. Need for the study: Vitamin D regulates the suppression of Interferon-Gamma (IFN-γ) and Interleukin-1 beta (IL-1β) production within the epithelium and its insufficiency may play a role in the development of OLP. Aim: To evaluate and compare the serum concentrations of IL-1β and Vitamin D in patients affected by OLP and in healthy subjects. Materials and Methods: A case-control study will be conducted in the Department of Oral Medicine and Radiology at Sharad Pawar Dental College, Datta Meghe Institute of Higher Education and Research, located in Maharashtra, India, from August 2024 to August 2026. Patients who present to the Department of Oral Medicine and Radiology and express willingness to participate will be enrolled in the study. Each patient will undergo a comprehensive clinical examination and provide written consent after being informed about the study. A thorough intraoral clinical assessment of the lesions will be conducted. Once a patient is clinically diagnosed with OLP, serum sample collection will be performed. Similarly, healthy subjects who are willing to participate in the study will also undergo sample collection. The median cubital vein will be punctured to obtain 2.5 mL of blood under aseptic conditions. The electrochemiluminescence-binding assay will then be conducted to quantify the total amounts of 25- hydroxy vitamin D and Interleukin-1 beta. After sample collection, patients with OLP will be educated and counseled regarding the treatment of OLP and habit cessation. Statistical analysis will be performed using an unpaired t-test, with a p-value considered significant at a 5% level of significance.

Commit to your putting stroke: exploring the impact of quiet eye duration and neural activity on golf putting performance.

There is a growing interest in characterizing the cognitive-motor processes that underlie superior performance in highly skilled athletes. The aim of this study was to explore neural markers of putting performance in highly skilled golfers by recording mobile EEG (electroencephalogram) during the pre-shot period. Twenty-eight right-handed participants (20 males) with a mean age of 24.2 years (± 6.4) and an average handicap of +1.7 (± 6.4) completed a testing session. Following the warm-up, participants completed 140 putts from a distance of 8ft (2.4m), with putts taken from 5 different positions. While putting, participants wore an eye tracker and a gel-based EEG system with 32 electrodes. Time and frequency domain features of the EEG signals were extracted to characterize Movement-Related Cortical Potentials (MRCP) and rhythmic modulations of neural activity in theta, alpha, sensorimotor and beta frequency bands associated with putting performance. Eye-tracking data demonstrate that mean Quiet Eye durations are not a reliable marker of expertise as the same duration was found for both successful and unsuccessful putts. Following rigorous data processing data from 12 participants (8 males, mean age 21.6 years ± 5.4, average handicap +1.5 ± 4.4) were included in the EEG analysis. MRCP analysis revealed performance-based differences, with unsuccessful putts having a greater negative amplitude in comparison to successful putts. Time frequency analysis of the EEG data revealed that successful putts exhibit distinct neural activity profiles compared to unsuccessful ones. For successful putts, greater suppression of beta was present in the central region prior to the putt. By contrast, increased frontal theta power was present for unsuccessful putts immediately before the putt (consistent with hesitation and the need for motor plan adjustments prior to execution). We propose that neural activity may provide plausible insights into the mechanisms behind why identical QE durations can lead to both success and failure. From an applied perspective, this study highlights the merits of a multi-measure approach to gain further insights into performance differences within highly skilled golfers. We discuss considerations for future research and solutions to address the challenges related to the complexities of collecting clean EEG signals within naturalistic sporting contexts.

Average power and burst analysis revealed complementary information on drug-related changes of motor performance in Parkinson’s disease

In patients with Parkinson’s disease (PD), suppression of beta and increase in gamma oscillations in the subthalamic nucleus (STN) have been associated with both levodopa treatment and motor functions. Recent results suggest that modulation of the temporal dynamics of theses oscillations (bursting activity) might contain more information about pathological states and behaviour than their average power. Here we directly compared the information provided by power and burst analyses about the drug-related changes in STN activities and their impact on motor performance within PD patients. STN local field potential (LFP) signals were recorded from externalized patients performing self-paced movements ON and OFF levodopa. When normalised across medication states, both power and burst analyses showed an increase in low-beta oscillations in the dopamine-depleted state during rest. When normalised within-medication state, both analyses revealed that levodopa increased movement-related modulation in the alpha and low-gamma bands, with higher gamma activity around movement predicting faster reaches. Finally, burst analyses helped to reveal opposite drug-related changes in low- and high-beta frequency bands, and identified additional within-patient relationships between high-beta bursting and movement performance. Our findings suggest that although power and burst analyses share a lot in common they also provide complementary information on how STN-LFP activity is associated with motor performance, and how levodopa treatment may modify these relationships in a way that helps explain drug-related changes in motor performance. Different ways of normalisation in the power analysis can reveal different information. Similarly, the burst analysis is sensitive to how the threshold is defined – either for separate medication conditions separately, or across pooled conditions. In addition, the burst interpretation has far-reaching implications about the nature of neural oscillations – whether the oscillations happen as isolated burst-events or are they sustained phenomena with dynamic amplitude variations? This can be different for different frequency bands, and different for different medication states even for the same frequency band.

Endoplasmic reticulum stress response and the regulation of endometrial interferon-beta production

To gain an understanding of the potential role of endoplasmic reticulum (ER) stress in the endometrial compartment during early pregnancy, a highly understudied area. This study examined the regulation of interferon-β (IFNβ) in response to ER stress in human decidualized and nondecidualized endometrial cells (human endometrial stromal cells [HESCs]) invitro. Invivo, we examined ER stress and the IFNβ levels locally in the mouse endometrium before and after implantation at embryonic day (E)1, E3, and E6. The study was performed in a reproductive sciences laboratory for Human Growth and Development. None. None. Quantitative polymerase chain reaction, Western blotting, and immunohistochemical analysis allowed us to test the action of endogenous ER stress activation in the endometrial compartment likely triggered by implantation and its ability to increase the endometrial IFNβ levels. Invitro, we observed a significant difference in the IFNβ levels in HESCs, in response to ER stress activation, where decidualized HESCs exhibited a threefold increase in the IFNβ levels compared with nondecidualized HESCs. Apoptotic caspase-3 activation was also isolated to the decidualized cells as a result of ER stress-dependent suppression of nuclear factor-kappa beta-regulated antiapoptotic factors, XIAP and MCL-1. Invivo, mouse endometrial IFNβ was present in F4/80-positive macrophages at all time points examined. After implantation (E6), the mouse luminal epithelial cells robustly coexpressed both IFNβ and the ER stress marker immunoglobulin heavy chain binding protein (BiP). These analyses demonstrate that both invivo and invitro, differentiated and decidualized endometrial cells undergoing ER stress have the capacity to produce increased IFNβ levels; therefore, ER stress activation in the endometrial compartment may play a vital role in promoting successful implantation events.

Saturated Fatty Acid-Induced Endoplasmic Reticulum Stress and Insulin Resistance Are Prevented by Imoxin in C2C12 Myotubes.

In obesity, plasma free fatty acids (FFAs) levels are elevated due to enlarged adipose tissue mass. Saturated fatty acids can induce prolonged ER stress and insulin resistance. Double-stranded RNA-dependent Protein Kinase (PKR) is activated under stress conditions in skeletal muscle. The current study aimed to investigate the effect of imoxin (IMX), a selective PKR inhibitor, on palmitate-induced ER stress and insulin resistance in C2C12 myotubes. Cells were treated with 5 μM imoxin and exposed to 0.5 mM bovine serum albumin (BSA)-conjugated PA for 24 h. A subset of cells was stimulated with 50 nM insulin for the last 15 min. Glucose uptake was monitored and protein levels involved in ER stress and insulin signaling were measured by Western blotting. Palmitate stimulated PKR phosphorylation, which was prevented by imoxin. Moreover, imoxin reduced protein levels of ER stress-related markers including glucose-regulating protein 78 (GRP78), CCAAT-enhancer-binding protein homologous protein (CHOP), activating transcription factor 6 (ATF6) and spliced X-box binding protein 1 (XBP-1s) which were induced by palmitate. Furthermore, imoxin ameliorated palmitate-induced suppression of phospho-insulin receptor beta (p-IRβ) and Akt phosphorylation in myotubes. In addition, imoxin promoted glucose uptake in response to insulin under palmitate exposure. Furthermore, imoxin reduced phospho-c-Jun N-terminal kinase (p-JNK) induced by palmitate treatment. These findings suggest that imoxin may protect against saturated fatty acid-induced ER stress and insulin resistance in skeletal muscle, which are potentially mediated by PKR.

Aberrant slow waves in the hippocampus during activation in mice with low cholinergic tone.

The effects of acetylcholine on cortical activation were studied in wild-type (WT) mice, compared to knockout (KO) mice depleted of the vesicular acetylcholine transporter (VAChT) gene in the basal forebrain, and knockdown (KD) mice with heterogeneous depletion of VAChT gene in the brain. Cortical activation was assessed by comparing power spectra of local field potentials (LFPs) during activated states of rapid-eye-movement sleep (REM) or walk (WLK), with those during non-activated states of slow-wave sleep (SWS) or awake-immobility (IMM). Activation-induced suppression of delta (1-4Hz) and beta (13-30 Hz) power in the hippocampus, and delta power in frontal cortex, were reduced in KO and KD mice compared to WT mice. Mean theta frequency was higher in KD than KO mice during WLK and REM, but not different between WT and KO mice. Peak theta (4-12 Hz) and integrated gamma (30-150 Hz) power were not significantly different among mouse groups. However, theta-peak-frequency selected gamma2 (62-100 Hz) power was lower in KO than WT or KD mice during WLK, and theta-peak-frequency selected theta power during REM decreased faster with high theta frequency in KO than WT/ KD mice. Theta power increase during REM compared to WLK was lower in KO and KD mice compared to WT mice. Theta-gamma cross-frequency coherence, a measure of synchronization of gamma with theta phase, was not different among mouse groups. However, during REM, SWS, and IMM, delta-gamma coherence was significantly higher and proximal-distal delta coherence in CA1 was lower in KO than WT/KD mice. We conclude that a deficiency in basal forebrain acetylcholine release not only enhances slow waves and suppresses theta-associated gamma waves during activation, but also increases delta-gamma cross-frequency coherence during nonactivated states, with a possible effect of disrupting cognitive processing during any brain state.

Suppression of beta 2 adrenergic receptor actions prevent UVB mediated cutaneous squamous cell tumorigenesis through inhibition of VEGF-A induced angiogenesis.

Although beta 2 adrenergic receptors (β2 ADR) are present in the keratinocytes, their role in cutaneous squamous cell tumorigenesis needs to be ascertained. For the first time, we report here that selective β2 ADR antagonists by inhibiting β2 ADR actions significantly retarded the progression of ultraviolet B (UVB) induced premalignant cutaneous squamous cell lesions. These antagonists acted by inhibiting vascular endothelial growth factor-A (VEGF) mediated angiogenesis to prevent UVB radiation-induced squamous cell carcinoma of the skin.

Vibration Alert to the Brain: Evoked and Induced MEG Responses to High-Frequency Vibrotactile Stimuli on the Index Finger of Dominant and Non-dominant Hand.

Background: In recent years, vibrotactile haptic feedback technology has been widely used for user interfaces in the mobile devices. Although functional neuroimaging studies have investigated human brain responses to different types of tactile inputs, the neural mechanisms underlying high-frequency vibrotactile perception are still relatively unknown. Our aim was to investigate neuromagnetic brain responses to high-frequency vibrotactile stimulation, using magnetoencephalography (MEG).Methods: We measured 152-channel whole-head MEG in 30 healthy, right-handed volunteers (aged 20–28 years, 15 females). A total of 300 vibrotactile stimuli were presented at the tip of either the left index finger or the right index finger in two separate sessions. Sinusoidal vibrations at 150 Hz for 200 ms were generated with random inter-stimulus intervals between 1.6 and 2.4 s. Both time-locked analysis and time-frequency analysis were performed to identify peak responses and oscillatory modulations elicited by high-frequency vibrations. The significance of the evoked and induced responses for dominant and non-dominant hand stimulation conditions was statistically tested, respectively. The difference in responses between stimulation conditions was also statistically evaluated.Results: Prominent peak responses were observed at 56 ms (M50) and at 100 ms (M100) for both stimulation conditions. The M50 response revealed clear dipolar field patterns in the contralateral side with significant cortical activations in the contralateral primary sensorimotor area, whereas the M100 response was not as prominent as the M50. Vibrotactile stimulation induced significant suppression of both alpha (8–12 Hz) and beta (20–30 Hz) band activity during the mid-latency period (0.2–0.4 s), primarily in sensorimotor areas contralateral to the stimulation side. In addition, a significant alpha enhancement effect in posterior regions was accompanied with alpha suppressions in sensorimotor regions. The alpha suppression was observed in a broader distribution of cortical areas for the non-dominant hand stimulation.Conclusion: Our data demonstrate that high-frequency tactile vibrations, which is known to primarily activate Pacinian corpuscles, elicit somatosensory M50 and M100 responses in the evoked fields and induce modulations of alpha and beta band oscillations during mid-latency periods. Our study is also consistent with that the primary sensorimotor area is significantly involved in the processing of high-frequency vibrotactile information with contralateral dominance.

Neuromodulation effects of deep brain stimulation on beta rhythm: A longitudinal local field potential study

BackgroundDeep brain stimulation (DBS) holds great promise in treating various brain diseases but its chronic therapeutic mechanisms are unclear. ObjectiveTo explore the immediate and chronic effects of DBS on brain oscillations, and understand how different sub-bands of oscillations may be related to symptom improvement in Parkinson's patients. MethodsWe carried out a longitudinal study to examine the effects of DBS on local field potentials recorded by sensing-enabled neurostimulators in the subthalamic nuclei of Parkinson's patients, using a novel block-design stimulation paradigm. ResultsDBS significantly suppressed beta activity (13–35Hz) but the suppression effect appeared to gradually attenuate during a 6-month follow-up period after surgery (p = 0.002). However, beta suppression did not attenuate after repeated stimulation over several minutes (p > 0.110), suggesting that the changes in beta suppression may reflect a slow reconfiguration of neural pathways instead of habituation. Suppression of beta was also associated with clinical symptom improvement across subjects. Importantly, symptom-relevant features fell within the high beta band at month 1 but shifted to the low beta band at month 6, indicating that the high beta and the low beta oscillations may play different functional roles and respond differently to stimulation over the long-term treatment. ConclusionThese data may advance understanding of chronic DBS effects on beta oscillations and their association with clinical improvement, offering novel insights to the therapeutic mechanisms of DBS.

Quantitative Electroencephalogaphy (QEEG) and Neurofeedback Training (NFT) for Elderly with Mild Cognitive Impairment (MCI)

Neurofeedback training (NFT) has been widely used to alter the brain activity to enhance the brain function. This study aimed to apply neurofeedback to enhance the cognitive performance in elderly with Mild Cognitive Impairment (MCI) by focusing on alpha wave in the neurofeedback training as it is positively associated with cognitive decline in elderly. 10 subjects who passed the criteria were assigned to experimental and control group. With 15 sessions of alpha neurofeedback, increase in alpha absolute power was rewarded while simultaneous suppression of theta and beta2 were done in experimental group. Results showed that after completion of neurofeedback, all subjects in experimental group learn to increase their alpha absolute power while mixed result was recorded for suppression of theta and high beta either at individual, inter and intra group level. Cognitive results in individual level revealed that pattern of increase and decrease of score was regular in experimental group and at grouped level, significant increment observed in Digit Span and Symbol Search in experimental group only. These results suggest that MCI elderly could learn to increase specific components of EEG activity that such enhanced activity may facilitate in working memory and processing speed enhancement.

Early intervention with glucagon-like peptide 1 analog liraglutide prevents tau hyperphosphorylation in diabetic db/db mice.

Increasing evidence has shown that type 2 diabetes (T2D) is a risk factor for Alzheimer's disease. Neurofibrillary tangles, which consist of hyperphosphorylated tau and misfolded microtubules, is one of the neuropathological hallmarks of Alzheimer's disease. Db/db mice, a rodent model of T2D, also exhibited age-dependent tau hyperphosphorylation. Glucagon-like peptide-1 (GLP-1) mimetics, a type of drug used in T2D, has been found to have neuroprotective effects. The aim of this study was to explore the potential effects of liraglutide (a GLP-1 analog), or insulin, on tau phosphorylation in T2D animals. Male db/db mice (3-3.5 weeks) were daily injected subcutaneously with liraglutide (n = 27), insulin (n = 27), or saline (n = 26), and five to seven mice were killed every 2 weeks for analysis of plasma and cerebrospinal (CSF) insulin levels by ELISA, and protein levels in the hippocampal formation by western blot. We found that db/db mice treated with saline exhibited an age-dependent decrease in CSF insulin and an increase in hippocampal tau phosphorylation. Liraglutide injection reversed the CSF insulin to ~1 mIU/L by the end of 8 weeks treatment, and prevented the hyperphosphorylation of tau protein in the hippocampal formation. By contrast, insulin injection had no effects on CSF insulin or phosphorylation of tau protein. In summary, this study indicates that early GLP-1 analog intervention prevented the age-dependent tau hyperphosphorylation in T2D mice brain, probably by facilitating sequential activation in an insulin signaling pathway reflected in increased basal activation of Akt and basal suppression of glycogen synthase kinase-3 beta.

Grasping hand verbs: oscillatory beta and alpha correlates of action-word processing.

The grounded cognition framework proposes that sensorimotor brain areas, which are typically involved in perception and action, also play a role in linguistic processing. We assessed oscillatory modulation during visual presentation of single verbs and localized cortical motor regions by means of isometric contraction of hand and foot muscles. Analogously to oscillatory activation patterns accompanying voluntary movements, we expected a somatotopically distributed suppression of beta and alpha frequencies in the motor cortex during processing of body-related action verbs. Magnetoencephalographic data were collected during presentation of verbs that express actions performed using the hands (H) or feet (F). Verbs denoting no bodily movement (N) were used as a control. Between 150 and 500 msec after visual word onset, beta rhythms were suppressed in H and F in comparison with N in the left hemisphere. Similarly, alpha oscillations showed left-lateralized power suppression in the H-N contrast, although at a later stage. The cortical oscillatory activity that typically occurs during voluntary movements is therefore found to somatotopically accompany the processing of body-related verbs. The combination of a localizer task with the oscillatory investigation applied to verb reading as in the present study provides further methodological possibilities of tracking language processing in the brain.

Large Study Links Lifetime of Coffee Drinking to Lower Dementia Risk in Later Years

Large Study Links Lifetime of Coffee Drinking to Lower Dementia Risk in Later Years

How bodies and voices interact in early emotion perception.

Successful social communication draws strongly on the correct interpretation of others' body and vocal expressions. Both can provide emotional information and often occur simultaneously. Yet their interplay has hardly been studied. Using electroencephalography, we investigated the temporal development underlying their neural interaction in auditory and visual perception. In particular, we tested whether this interaction qualifies as true integration following multisensory integration principles such as inverse effectiveness. Emotional vocalizations were embedded in either low or high levels of noise and presented with or without video clips of matching emotional body expressions. In both, high and low noise conditions, a reduction in auditory N100 amplitude was observed for audiovisual stimuli. However, only under high noise, the N100 peaked earlier in the audiovisual than the auditory condition, suggesting facilitatory effects as predicted by the inverse effectiveness principle. Similarly, we observed earlier N100 peaks in response to emotional compared to neutral audiovisual stimuli. This was not the case in the unimodal auditory condition. Furthermore, suppression of beta–band oscillations (15–25 Hz) primarily reflecting biological motion perception was modulated 200–400 ms after the vocalization. While larger differences in suppression between audiovisual and audio stimuli in high compared to low noise levels were found for emotional stimuli, no such difference was observed for neutral stimuli. This observation is in accordance with the inverse effectiveness principle and suggests a modulation of integration by emotional content. Overall, results show that ecologically valid, complex stimuli such as joined body and vocal expressions are effectively integrated very early in processing.

Caffeine and Coffee as Therapeutics Against Alzheimer's Disease

Epidemiologic studies have increasingly suggested that caffeine/coffee could be an effective therapeutic against Alzheimer's disease (AD). We have utilized a transgenic mouse model for AD in well-controlled studies to determine if caffeine and/or coffee have beneficial actions to protect against or reverse AD-like cognitive impairment and AD pathology. AD mice given caffeine in their drinking water from young adulthood into older age showed protection against memory impairment and lower brain levels of the abnormal protein (amyloid-beta; Abeta) thought to be central to AD pathogenesis. Moreover, "aged" cognitively-impaired AD mice exhibited memory restoration and lower brain Abeta levels following only 1-2 months of caffeine treatment. We believe that the cognitive benefits of chronic caffeine administration in AD mice are due to caffeine itself, and not metabolites of caffeine; this, because our long-term administration of theophylline to AD mice provided no cognitive benefits. In acute studies involving AD mice, one oral caffeine treatment quickly reduced both brain and plasma Abeta levels - similarly rapid alterations in plasma Abeta levels were seen in humans following acute caffeine administration. "Caffeinated" coffee provided to AD mice also quickly decreased plasma Abeta levels, but not "decaffeinated" coffee, suggesting that caffeine is critical to decreasing blood Abeta levels. Caffeine appears to provide its disease-modifying effects through multiple mechanisms, including a direct reduction of Abeta production through suppression of both beta- and gamma-secretase levels. These results indicate a surprising ability of moderate caffeine intake (the human equivalent of 500 mg caffeine or 5 cups of coffee per day) to protect against or treat AD in a mouse model for the disease and a therapeutic potential for caffeine against AD in humans.

Sex-Related Differences in Cortical Inhibition to Repeated Electrical Stimulation in Adolescents

Event Abstract Back to Event Sex-Related Differences in Cortical Inhibition to Repeated Electrical Stimulation in Adolescents Colleen Dockstader1*, Rosemary Tannock2, Karen D. Davis3, Patricia A. McGrath1 and Douglas Cheyne4, 5 1 The Hospital for Sick Children, Department of Anesthesia and Pain Medicine, Canada 2 The Hospital for Sick Children, Department of Psychiatry, Canada 3 University of Toronto, Brain, Imaging and Behaviour-Systems Neuroscience, Toronto Western Research Institute, Canada 4 Hospital for Sick Children, Program in Neurosciences and Mental Health, Canada 5 University of Toronto, Department of Medical Imaging, Canada Sex-related differences in tactile sensitivities emerge around puberty. However, while studies confirm that there are sex differences in behavioural and neural responses to repeated electrical stimuli in adults, no studies have evaluated sex differences to repeated electrical stimuli during development. We measured the neuromagnetic changes in cortical oscillations of the primary somatosensory cortex (SI) in response to repetitive, unpleasant (but nonpainful) median nerve stimulation for male and female adolescents (5M, mean age = 14.8 years +/- 1.5 SD; 5F, mean age = 15.6 years +/- 2.3 SD) over an 11-minute period. Sources in SI were localized using a beamformer method (synthetic aperture magnetometry). We then computed time-frequency plots of source power over the interval of –50ms to 600 ms, for 4 consecutive blocks of 200 trials each using a Morlet wavelet transform. Male and female adolescents showed a similar response during the first block of 200 stimuli, with a broad-spectrum (1-200 Hz) burst of activity at ~20 ms followed by suppression of mu (8-12 Hz) and beta (13-29 Hz) rhythmic activity and a subsequent beta rebound, although males showed higher overall power. Over repeated blocks, males showed consistent mu suppression but decreased beta suppression and increased beta rebound. To the contrary, females showed increasingly less mu response and reduced beta rebound over repeated blocks of median nerve stimulation. Since sensorimotor beta rebound occurs during states of cortical inhibition (when domain-specific processing is suppressed), our data suggest that adolescent males show increasing cortical inhibition in response to persistent electrical stimulation whereas adolescent females show the opposite trend. Sex-related differences in cortical inhibition to persistent somatosensory stimuli may suggest differential central mechanisms underlying adaptation to persistent stimuli, emerging as early as adolescence. Conference: Biomag 2010 - 17th International Conference on Biomagnetism , Dubrovnik, Croatia, 28 Mar - 1 Apr, 2010. Presentation Type: Poster Presentation Topic: Sensory Processing and Functional Connectivity Citation: Dockstader C, Tannock R, Davis KD, McGrath PA and Cheyne D (2010). Sex-Related Differences in Cortical Inhibition to Repeated Electrical Stimulation in Adolescents. Front. Neurosci. Conference Abstract: Biomag 2010 - 17th International Conference on Biomagnetism . doi: 10.3389/conf.fnins.2010.06.00163 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 26 Mar 2010; Published Online: 26 Mar 2010. * Correspondence: Colleen Dockstader, The Hospital for Sick Children, Department of Anesthesia and Pain Medicine, Toronto, Canada, colleen.dockstader@sickkids.ca Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Colleen Dockstader Rosemary Tannock Karen D Davis Patricia A McGrath Douglas Cheyne Google Colleen Dockstader Rosemary Tannock Karen D Davis Patricia A McGrath Douglas Cheyne Google Scholar Colleen Dockstader Rosemary Tannock Karen D Davis Patricia A McGrath Douglas Cheyne PubMed Colleen Dockstader Rosemary Tannock Karen D Davis Patricia A McGrath Douglas Cheyne Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Expectations about upcoming tactile events selectively modulate beta-band oscillations in human primary somatosensory cortex

Event Abstract Back to Event Expectations about upcoming tactile events selectively modulate beta-band oscillations in human primary somatosensory cortex Freek V. Ede1*, Ole Jensen1 and Eric Maris1 1 Radboud University Nijmegen, Donders Institute for Brain, Cognition and Behaviour, Netherlands Neuronal oscillations are postulated to play a fundamental role in top-down processes of expectation. We used magnetoencephalogaphy (MEG) to investigate whether expectation of a tactile event involves a pre-stimulus modulation of neuronal oscillations in human somatosensory cortex. In a bimodal attention paradigm, participants were presented with a predictable spatio-temporal pattern of tactile stimulations and simultaneously occurring non-lateralized auditory stimuli. By investigating lateralized patterns of oscillatory activity, we studied both attentive and non-attentive tactile expectation. For both, we observe a lateralized modulation of oscillatory activity in the beta-band prior to a predictable – and accordingly lateralized – tactile stimulus. Topography and lateralization imply an origin in primary somatosensory cortex (S1). We propose that beta – a dominant rhythm in S1 – drives neuronal excitability in an a-specific manner such that perceptual processing requires suppression of it. Expectation-induced suppression of beta then prepares the system for processing, leading the active process of perception to start even prior to sensation. Conference: Biomag 2010 - 17th International Conference on Biomagnetism , Dubrovnik, Croatia, 28 Mar - 1 Apr, 2010. Presentation Type: Poster Presentation Topic: Neurocognition and Functional Connectivity Citation: Ede FV, Jensen O and Maris E (2010). Expectations about upcoming tactile events selectively modulate beta-band oscillations in human primary somatosensory cortex. Front. Neurosci. Conference Abstract: Biomag 2010 - 17th International Conference on Biomagnetism . doi: 10.3389/conf.fnins.2010.06.00333 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 06 Apr 2010; Published Online: 06 Apr 2010. * Correspondence: Freek V Ede, Radboud University Nijmegen, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, Netherlands, f.vanede@donders.ru.nl Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Freek V Ede Ole Jensen Eric Maris Google Freek V Ede Ole Jensen Eric Maris Google Scholar Freek V Ede Ole Jensen Eric Maris PubMed Freek V Ede Ole Jensen Eric Maris Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Roles of PKC isoforms in the induction of apoptosis elicited by aberrant Ras

Emerging evidence indicates that suppression of protein kinase C (PKC) renders the susceptibility of cells expressing mutated ras to apoptosis. Although the effort has been made, the underlying molecular mechanisms are not fully understood. In this study, using small hairpin RNAs (shRNAs) or PKC inhibitor, we show that the concurrent suppression of PKC-alpha and beta induces cells ectopically expressing v-ras to undergo apoptosis. In this apoptotic process, PKC-delta is upregulated and translocated from the cytosol to the nucleus. The activated PKC-delta associates with and phosphorylates p73 to initiate apoptosis. In this apoptotic process, Akt seems to be downstream of oncogenic Ras. Moreover, overexpression of PKC-delta, without co-suppression of PKC-alpha and beta, is not apoptotic to the cells, suggesting that PKC-delta and PKC-alpha/beta function oppositely to facilitate cells harboring v-ras to survive. Thus, our study shows that PKC-alpha and beta are necessary for sustaining the homeostasis in cells containing a hyperactive Ras. The abrogation of these two isoforms switches on the p73-regulated apoptotic machinery through the activation of PKC-delta.