Effects of dry needling on spasticity, cortical excitability, and range of motion in a patient with multiple sclerosis: a case report.

BACKGROUND: Dry needling is an intervention used by physiotherapists to manage muscle spasticity. We report the effects of three sessions of dry needling on ankle plantar flexor muscle spasticity and cortical excitability in a patient with multiple sclerosis. CASE PRESENTATION: The patient was a 40-year-old Iranian woman with an 11-year history of multiple sclerosis. The study outcomes were measured by the modified modified Ashworth scale, transcranial magnetic stimulation parameters, and active and passive ankle range of motion. They were assessed before (T0), after three sessions of dry needling (T1), and at 2-week follow-up (T2). Our result showed: the modified modified Ashworth scale was improved at T2 from, 2 to 1. The resting motor threshold decreased from 63 to 61 and 57 at T1 and T2, respectively. The single test motor evokes potential increased from 76.2 to 78.3. The short intracortical inhibition increased from 23.6 to 35.4 at T2. The intracortical facilitation increased from 52 to 76 at T2. The ankle active and passive dorsiflexion ROM increased ~ 10° and ~ 6° at T2, respectively. CONCLUSION: This case study presented a patient with multiple sclerosis who underwent dry needling of ankle plantar flexors with severe spasticity, and highlighted the successful use of dry needling in the management of spasticity, ankle dorsiflexion, and cortical excitability. Further rigorous investigations are warranted, employing randomized controlled trials with a sufficient sample of patients with multiple sclerosis. Trial registration IRCT20230206057343N1, registered 9 February 2023, https://en.irct.ir/trial/68454.

Incorporating EEG and fNIRS Patterns to Evaluate Cortical Excitability and MI-BCI Performance During Motor Training.

As electroencephalography (EEG) is nonlinear and nonstationary in nature, an imperative challenge for brain-computer interfaces (BCIs) is to construct a robust classifier that can survive for a long time and monitor the brain state stably. To this end, this research aims to improve BCI performance by incorporation of electroencephalographic and cerebral hemodynamic patterns. A motor imagery (MI)-BCI based visual-haptic neurofeedback training (NFT) experiment was designed with sixteen participants. EEG and functional near infrared spectroscopy (fNIRS) signals were simultaneously recorded before and after this transient NFT. Cortical activation was significantly improved after repeated and continuous NFT through time-frequency and topological analysis. A classifier calibration strategy, weighted EEG-fNIRS patterns (WENP), was proposed, in which elementary classifiers were constructed by using both the EEG and fNIRS information and then integrated into a strong classifier with their independent accuracy-based weight assessment. The results revealed that the classifier constructed on integrating EEG and fNIRS patterns was significantly superior to that only with independent information (  âˆ¼  10% and  âˆ¼  18% improvement respectively), reaching  âˆ¼  89% in mean classification accuracy. The WENP is a classifier calibration strategy that can effectively improve the performance of the MI-BCI and could also be used to other BCI paradigms. These findings validate that our proposed methods are feasible and promising for optimizing conventional motor training methods and clinical rehabilitation.

Presença de risco de transtorno do estresse pós-traumático em policiais militares feridos por arma de fogo / Presence of risk of posttraumatic stress disorder in military police officers wounded by firearms / Presencia de riesgo de trastorno de estrés postraumático en policías militares heridos por armamiento de fuego

Este estudo teve como objetivo identificar o risco de desenvolvimento de transtorno de estresse pós-traumático (TEPT), bem como sua associação com pensamentos ou tentativas suicidas e a saúde mental de policiais militares feridos por arma de fogo, na Região Metropolitana de Belém (RMB), nos anos de 2017 a 2019. A pesquisa contou com a participação de 30 entrevistados, que responderam o Inventário Demográfico e a Lista de verificação de TEPT para o DSM-5 (PCL-5). Para análise dos dados, utilizou-se a técnica estatística Análise Exploratória de Dados e a técnica multivariada Análise de Correspondência. Os resultados revelaram a existência de risco de desenvolvimento do transtorno de forma parcial ou total em uma expressiva parcela da população entrevistada, tendo homens como maioria dos sintomáticos, com média de 38 anos, exercendo atividades operacionais e vitimados em via pública quando estavam de folga do serviço. O ferimento deixou a maioria com sequelas, com destaque para dores crônicas, limitações de locomoção e/ou mobilidade e perda parcial de um membro. E, ainda, policiais sintomáticos apresentaram comportamentos suicidas, relatando já terem pensado ou tentado tirar a própria vida. Desta forma, conclui-se que policiais militares são expostos constantemente a traumas inerentes a sua profissão. Quando há ameaça de vida, como nos casos de ferimentos por arma de fogo, são suscetíveis a sequelas físicas decorrente do ferimento, somadas a sequelas mentais tardias, como o surgimento de sintomatologias de TEPT e ideação suicida.(AU)

This study aimed to identify the risk of developing post-traumatic stress disorder (PTSD) and its associations around suicidal thoughts or attempts and mental health in military police officers injured by firearms, in the Metropolitan Region of Belem (RMB), from 2017 to 2019. The research had the participation of 30 respondents who answered the Demographic Inventory and the PTSD checklist for DSM-5 (PCL-5). For data analysis, we used the statistical technique Exploratory Data Analysis and the multivariate technique Correspondence Analysis. The results revealed the existence of risk of developing partial or total disorder in a significant portion of the interviewed population, with men as most of the symptomatic individuals, with mean age of 38 years, developing operational activities and victimized on public roads when they were off duty. The injuries left most of them with sequelae, especially chronic pain, limited locomotion and/or mobility, and partial loss of a limb. In addition, symptomatic officers showed suicidal behavior, such as reporting they had thought about or tried to take their own lives. Thus, we conclude that military policemen are constantly exposed to traumas inherent to their profession. When their lives are threatened, as in the case of firearm wounds, they are susceptible to physical sequelae resulting from the injury, in addition to late mental sequelae, such as the appearance of PTSD symptoms and suicidal ideation.(AU)

Este estudio tuvo como objetivo identificar el riesgo de desarrollo de trastorno de estrés postraumático (TEPT) y sus asociaciones con pensamientos o tentativas suicidas y la salud mental en policías militares heridos por armamiento de fuego, en la Región Metropolitana de Belém (Brasil), en el período entre 2017 y 2019. En el estudio participaron 30 entrevistados que respondieron el Inventario Demográfico y la Lista de verificación de TEPT para el DSM-5 (PCL-5). Para el análisis de datos se utilizaron la técnica estadística Análisis Exploratoria de Datos y la técnica multivariada Análisis de Correspondencia. Los resultados revelaron que existen riesgos de desarrollo de trastorno de estrés postraumático de forma parcial o total en una expresiva parcela de la población de policías entrevistados, cuya mayoría de sintomáticos eran hombres, de 38 años en media, que ejercen actividades operacionales y fueron victimados en vía pública cuándo estaban de día libre del servicio. La lesión dejó la mayoría con secuelas, especialmente con dolores crónicos, limitaciones de locomoción y/o movilidad y la pierda parcial de un miembro. Aún los policías sintomáticos presentaran comportamiento suicida, tales como relataran qué ya pensaron o tentaron quitar la propia vida. Se concluye que los policías militaran se exponen constantemente a los traumas inherentes a su profesión. Cuando existe amenaza de vida, como en los casos de heridas por armamiento de fuego, son expuestos a secuelas físicas transcurridas de la herida, sumado a secuelas mentales tardías, como el surgimiento de sintomatologías de TEPT y la ideación suicida.(AU)

[Effect of electroacupuncture at back-shu points of five zang on fatigue status and cortical excitability in chronic fatigue syndrome].

OBJECTIVE: To observe the effect of electroacupuncture (EA) at back-shu points of five zang on fatigue status, quality of life and motor cortical excitability in patients with chronic fatigue syndrome (CFS), so as to explore the possible mechanism of EA for CFS. METHODS: A total of 72 patients with CFS were randomized into an EA group (36 cases, 4 cases dropped off) and a sham EA group (36 cases, 3 cases dropped off). In the EA group, EA at Ganshu (BL 18), Xinshu (BL 15), Pishu (BL 20), Feishu (BL 13) and Shenshu (BL 23) was adopted, with continuous wave, 2 Hz in frequency. In the sham EA group, sham EA at non-acupoints (1.5-2.0 cm lateral to back-shu points of five zang) was applied, with shallow needling, and no current was connected. The treatment in the both groups was 20 min each time, once every other day, 2 weeks as one course, 3 courses were required. Before and after treatment, the scores of fatigue scale-14 (FS-14) and the MOS 36-item short form health survey (SF-36) were observed, and cortical excitability (the resting motor threshold [RMT], amplitude of motor-evoked potential [MEP-A] and latency of motor-evoked potential [MEP-L]) was detected in the two groups. RESULTS: After treatment, the physical fatigue score, mental fatigue score and total score of FS-14, as well as RMT of motor cortex in the EA group were decreased compared with those before treatment (P<0.01), the physical fatigue score and total score of FS-14 in the sham EA group were decreased compared with those before treatment (P<0.05); each item score and total score of FS-14 and RMT of motor cortex in the EA group were lower than those in the sham EA group (P<0.01, P<0.05). After treatment, each item score and total score of SF-36 and MEP-A of motor cortex in the EA group were increased compared with those before treatment (P<0.01), which were higher than those in the sham EA group (P<0.01, P<0.05). CONCLUSION: EA at back-shu points of five zang can effectively improve the fatigue status and quality of life in patients with CFS, its mechanism may be related to the up-regulating excitability of cerebral motor cortex.

The Relationship Between Cortical Activation in Response to Anorectal Stimuli and Continence Behavior in Freely Behaving Rats Before and After Application of Sacral Nerve Stimulation.

BACKGROUND: Changes in anorectal sensation have been reported in patients with fecal incontinence, and there is limited evidence that sacral nerve stimulation can restore normal sensation. OBJECTIVE: The aims of the present study were to investigate changes in the transmission of sensory anorectal stimuli in a rodent model of fecal incontinence and to study the effects of sacral nerve stimulation on defecation behavior. DESIGN: An established model of fecal incontinence was utilized for this study. INTERVENTION: Pudendal nerve stretch and compression were used in 16 adult female Wistar rats and were monitored for 3 weeks: 6 rats received sacral nerve stimulation for 1 week by using an implantable neurostimulator and 10 rats had nonfunctioning "dummy" devices inserted. Five additional rats were sham operated. Anorectal cortical evoked potentials were used as a surrogate marker for anorectal sensory function. MAIN OUTCOME MEASURES: The primary outcomes measured were fecal incontinence index, evoked potential amplitude, and latency. RESULTS: Fifty percent of rats showed behavioral signs of fecal incontinence measured by the Fecal Incontinence Index (>0.20), calculated by using the pellet distribution outside the cage's latrine area. Anorectal evoked potential amplitude was reduced in rats with a Fecal Incontinence Index >0.20 (p = 0.019). The amplitude of forepaw evoked potentials recorded as a control was not different between groups. Chronic sacral nerve stimulation using the fully implantable device and custom rodent lead was safe and stable during this chronic prospective study. Incontinent rats (n = 3) that received sacral nerve stimulation showed an improvement of Fecal Incontinence Index and an increase of evoked potential amplitude to anorectal stimulation compared with the dummy implant controls (n = 5). LIMITATIONS: The main limitation is the small number of animals that received sacral nerve stimulation. CONCLUSIONS: Chronic sacral nerve stimulation is feasible in rats when miniature telemetric devices are used. Behavioral signs of fecal incontinence were positively correlated with the latency of anorectal evoked potentials. See Video Abstract at http://links.lww.com/DCR/B712.RELACIÓN ENTRE LA ACTIVACIÓN CORTICAL EN RESPUESTA A LOS ESTÍMULOS ANORRECTALES Y EL COMPORTAMIENTO DE CONTINENCIA EN RATAS QUE SE COMPORTAN LIBREMENTE ANTES Y DESPUÉS DE LA APLICACIÓN DE ESTIMULACIÓN DEL NERVIO SACRO. ANTECEDENTES: Se han informado cambios en la sensación anorrectal en pacientes con incontinencia fecal y hay evidencia limitada de que la estimulación del nervio sacro puede restaurar la sensación normal. OBJETIVO: Los objetivos del presente estudio fueron investigar los cambios en la transmisión de estímulos anorrectales sensoriales en un modelo de roedor de incontinencia fecal y estudiar los efectos de la estimulación del nervio sacro en la conducta de defecación. DISEO: Un modelo establecido de incontinencia fecal. INTERVENCIN: Se utilizó estiramiento y compresión del nervio pudendo en 16 ratas Wistar hembras adultas y se les realizó un seguimiento durante 3 semanas: seis ratas recibieron estimulación del nervio sacro durante 1 semana utilizando un neuroestimulador implantable y diez ratas tuvieron insertados dispositivos "ficticios" no funcionantes. Se operaron simuladamente cinco ratas adicionales. Los potenciales evocados corticales anorrectales se utilizaron como marcador subrogado de la función sensorial anorrectal. PRINCIPALES MEDIDAS DE RESULTADO: Índice de incontinencia fecal, amplitud de potenciales evocados y latencia. RESULTADOS: El cincuenta por ciento de las ratas mostró signos de comportamiento de incontinencia fecal medidos por el Índice de incontinencia fecal (> 0.20), calculado utilizando la distribución de heces fuera del área de la letrina de la jaula. La amplitud del potencial evocado anorrectal se redujo en ratas con un índice de incontinencia fecal >0.20 (p = 0.019). La amplitud de los potenciales evocados de la pata delantera registrados como control no fue diferente entre los grupos. La estimulación crónica del nervio sacro utilizando un dispositivo totalmente implantable y un cable de roedor personalizado fue segura y estable durante este estudio prospectivo crónico. Las ratas con incontinencia (N = 3) que recibieron estimulación del nervio sacro mostraron una mejora del índice de incontinencia fecal y un aumento de la amplitud del potencial evocado a la estimulación anorrectal en comparación con los controles de implante ficticio (N = 5). LIMITACIONES: La principal limitación es el pequeño número de animales que recibieron estimulación del nervio sacro. CONCLUSIONES: La estimulación crónica del nervio sacro es factible en ratas cuando se utilizan dispositivos telemétricos en miniatura. Los signos conductuales de incontinencia fecal se correlacionaron positivamente con la latencia de los potenciales evocados anorrectales. Consulte Video Resumen en http://links.lww.com/DCR/B712. (Traducción-Dr. Jorge Silva Velazco).

Influence of the visuo-proprioceptive illusion of movement and motor imagery of the wrist on EEG cortical excitability among healthy participants.

INTRODUCTION: Motor Imagery (MI) is a powerful tool to stimulate sensorimotor brain areas and is currently used in motor rehabilitation after a stroke. The aim of our study was to evaluate whether an illusion of movement induced by visuo-proprioceptive immersion (VPI) including tendon vibration (TV) and Virtual moving hand (VR) combined with MI tasks could be more efficient than VPI alone or MI alone on cortical excitability assessed using Electroencephalography (EEG). METHODS: We recorded EEG signals in 20 healthy participants in 3 different conditions: MI tasks involving their non-dominant wrist (MI condition); VPI condition; and VPI with MI tasks (combined condition). Each condition lasted 3 minutes, and was repeated 3 times in randomized order. Our main judgment criterion was the Event-Related De-synchronization (ERD) threshold in sensori-motor areas in each condition in the brain motor area. RESULTS: The combined condition induced a greater change in the ERD percentage than the MI condition alone, but no significant difference was found between the combined and the VPI condition (p = 0.07) and between the VPI and MI condition (p = 0.20). CONCLUSION: This study demonstrated the interest of using a visuo-proprioceptive immersion with MI rather than MI alone in order to increase excitability in motor areas of the brain. Further studies could test this hypothesis among patients with stroke to provide new perspectives for motor rehabilitation in this population.

A BCI-Based Vibrotactile Neurofeedback Training Improves Motor Cortical Excitability During Motor Imagery.

In this study, we address the issue of whether vibrotactile feedback can enhance the motor cortex excitability translated into the plastic changes in local cortical areas during motor imagery (MI) BCI-based training. For this purpose, we focused on two of the most notable neurophysiological effects of MI - the event-related desynchronization (ERD) level and the increase in cortical excitability assessed with navigated transcranial magnetic stimulation (nTMS). For TMS navigation, we used individual high-resolution 3D brain MRIs. Ten BCI-naive and healthy adults participated in this study. The MI (rest or left/right hand imagery using Graz-BCI paradigm) tasks were performed separately in the presence and absence of feedback. To investigate how much the presence/absence of vibrotactile feedback in MI BCI-based training could contribute to the sensorimotor cortical activations, we compared the MEPs amplitude during MI after training with and without feedback. In addition, the ERD levels during MI BCI-based training were investigated. Our findings provide evidence that applying vibrotactile feedback during MI training leads to (i) an enhancement of the desynchronization level of mu-rhythm EEG patterns over the contralateral motor cortex area corresponding to the MI of the non-dominant hand; (ii) an increase in motor cortical excitability in hand muscle representation corresponding to a muscle engaged by the MI.

Modulation in cortical excitability disrupts information transfer in perceptual-level stimulus processing.

Despite significant interest in the neural underpinnings of behavioral variability, little light has been shed on the cortical mechanism underlying the failure to respond to perceptual-level stimuli. We hypothesized that cortical activity resulting from perceptual-level stimuli is sensitive to the moment-to-moment fluctuations in cortical excitability, and thus may not suffice to produce a behavioral response. We tested this hypothesis using electrocorticographic recordings to follow the propagation of cortical activity in six human subjects that responded to perceptual-level auditory stimuli. Here we show that for presentations that did not result in a behavioral response, the likelihood of cortical activity decreased from auditory cortex to motor cortex, and was related to reduced local cortical excitability. Cortical excitability was quantified using instantaneous voltage during a short window prior to cortical activity onset. Therefore, when humans are presented with an auditory stimulus close to perceptual-level threshold, moment-by-moment fluctuations in cortical excitability determine whether cortical responses to sensory stimulation successfully connect auditory input to a resultant behavioral response.

DUNEuro-A software toolbox for forward modeling in bioelectromagnetism.

Accurate and efficient source analysis in electro- and magnetoencephalography using sophisticated realistic head geometries requires advanced numerical approaches. This paper presents DUNEuro, a free and open-source C++ software toolbox for the numerical computation of forward solutions in bioelectromagnetism. Building upon the DUNE framework, it provides implementations of modern fitted and unfitted finite element methods to efficiently solve the forward problems of electro- and magnetoencephalography. The user can choose between a variety of different source models that are implemented. The software's aim is to provide interfaces that are extendable and easy-to-use. In order to enable a closer integration into existing analysis pipelines, interfaces to Python and MATLAB are provided. The practical use is demonstrated by a source analysis example of somatosensory evoked potentials using a realistic six-compartment head model. Detailed installation instructions and example scripts using spherical and realistic head models are appended.

Spike Activity in the Ventromedial Nucleus of Rat Hypothalamus during Aging.

Spike activity of neurons in the ventromedial nucleus (VMN) of the hypothalamus in adult (6-8 months) and aged (2 years) male rats was studied by the in vivo extracellular method using stereotaxic insertion of microelectrodes. In all animals, firing frequency of most VMN neurons increased in response to glucose administration. However, in aged rats, the mean baseline and glucose-induced spike frequencies of VMN neurons were lower than in adult animals. These results support the hypothesis that aging is associated with a decrease in the functional activity of hypothalamic neurons.

Visual cortex cTBS increases mixed percept duration while a-tDCS has no effect on binocular rivalry.

Neuromodulation of the primary visual cortex using anodal transcranial direct current stimulation (a-tDCS) can alter visual perception and enhance neuroplasticity. However, the mechanisms that underpin these effects are currently unknown. When applied to the motor cortex, a-tDCS reduces the concentration of the inhibitory neurotransmitter gamma aminobutyric acid (GABA), an effect that has been linked to increased neuroplasticity. The aim of this study was to assess whether a-tDCS also reduces GABA-mediated inhibition when applied to the human visual cortex. Changes in visual cortex inhibition were measured using the mixed percept duration in binocular rivalry. Binocular rivalry mixed percept duration has recently been advocated as a direct and sensitive measure of visual cortex inhibition whereby GABA agonists decrease mixed percept durations and agonists of the excitatory neurotransmitter acetylcholine (ACH) increase them. Our hypothesis was that visual cortex a-tDCS would increase mixed percept duration by reducing GABA-mediated inhibition and increasing cortical excitation. In addition, we measured the effect of continuous theta-burst transcranial magnetic stimulation (cTBS) of the visual cortex on binocular rivalry dynamics. When applied to the motor or visual cortex, cTBS increases GABA concentration and we therefore hypothesized that visual cortex cTBS would decrease the mixed percept duration. Binocular rivalry dynamics were recorded before and after active and sham a-tDCS (N = 15) or cTBS (N = 15). Contrary to our hypotheses, a-tDCS had no effect, whereas cTBS increased mixed percepts during rivalry. These results suggest that the neurochemical mechanisms of a-tDCS may differ between the motor and visual cortices.

Anterior Cingulate Cortex and the Control of Dynamic Behavior in Primates.

The brain mechanism for controlling continuous behavior in dynamic contexts must mediate action selection and learning across many timescales, responding differentially to the level of environmental uncertainty and volatility. In this review, we argue that a part of the frontal cortex known as the anterior cingulate cortex (ACC) is particularly well suited for this function. First, the ACC is interconnected with prefrontal, parietal, and subcortical regions involved in valuation and action selection. Second, the ACC integrates diverse, behaviorally relevant information across multiple timescales, producing output signals that temporally encapsulate decision and learning processes and encode high-dimensional information about the value and uncertainty of future outcomes and subsequent behaviors. Third, the ACC signals behaviorally relevant information flexibly, displaying the capacity to represent information about current and future states in a valence-, context-, task- and action-specific manner. Fourth, the ACC dynamically controls instrumental- and non-instrumental information seeking behaviors to resolve uncertainty about future outcomes. We review electrophysiological and circuit disruption studies in primates to develop this point, discuss its relationship to novel therapeutics for neuropsychiatric disorders in humans, and conclude by relating ongoing research in primates to studies of medial frontal cortical regions in rodents.

[Effect of electrical stimulation with bilateral scalp acupuncture on time parameters in video fluoroscopic swallowing study and cortical excitability in patients with dysphagia after cortical stroke].

OBJECTIVE: To investigate the effect of electrical stimulation with bilateral scalp acupuncture on time parameters in video fluoroscopic swallowing study and cortical excitability in patients with dysphagia after cortical stroke, as well as its possible mechanism of action. METHODS: A total of 84 patients with dysphagia after cortical stroke were randomly divided into control group with 41 patients and observation group with 43 patients. The patients in the control group were given acupuncture based on acupoint selection for pseudobulbar palsy, and in addition to the treatment in the control group, the patients in the observation group were given electrical stimulation of bilateral scalp acupuncture, with acupuncture and pulse acupuncture at the lower 2/5 of the bilateral anterior oblique parietotemporal lines[on the line connecting Qianshencong (EX-HN1) to Xuanli (GB6)] and the lower 2/5 of the bilateral posterior oblique parietotemporal lines [on the line connecting Baihui (GV20)and Qubin (GB7)], with a needle retaining time of 30 minutes, once a day and 6 times a week for 3 weeks. Before treatment and after 3 weeks of treatment, oral delay time (ODT), oral transit time (OTT), pharyngeal delay time (PDT), and pharyngeal transit time (PTT) were compared between the two group; the Rosenbek Penetration-Aspiration Scale was used to evaluate penetration-aspiration and appro-ximate entropy (ApEn) of EEG nonlinear index. RESULTS: After treatment, both groups had significant reductions in ODT, OTT, PDT, PTT, and Rosenbek Penetration-Aspiration score and a significant increase in ApEn (P<0.05). Compared with the control group after treatment, the observation group had significant reductions in ODT and OTT (P<0.05) and significant increases in the ApEn values of bilateral central, parietal, and posterior temporal regions (P<0.05), while there were no significant differences in PDT, PTT, and Rosenbek Penetration-Aspiration score between the two groups (P>0.05). CONCLUSION: In addition to body acupuncture, electrical stimulation with bilateral scalp acupuncture can improve ODT and OTT in the treatment of patients with dysphagia after cortical stroke, which may be associated with the increased excitability of the swallowing cortex.

Cortical excitability controls the strength of mental imagery.

Mental imagery provides an essential simulation tool for remembering the past and planning the future, with its strength affecting both cognition and mental health. Research suggests that neural activity spanning prefrontal, parietal, temporal, and visual areas supports the generation of mental images. Exactly how this network controls the strength of visual imagery remains unknown. Here, brain imaging and transcranial magnetic phosphene data show that lower resting activity and excitability levels in early visual cortex (V1-V3) predict stronger sensory imagery. Further, electrically decreasing visual cortex excitability using tDCS increases imagery strength, demonstrating a causative role of visual cortex excitability in controlling visual imagery. Together, these data suggest a neurophysiological mechanism of cortical excitability involved in controlling the strength of mental images.

Application of oxytocin with low-level laser irradiation suppresses the facilitation of cortical excitability by partial ligation of the infraorbital nerve in rats: An optical imaging study.

The effects of current treatments for neuropathic pain are limited. Oxytocin is a novel candidate substance to relieve neuropathic pain, as demonstrated in various animal models with nerve injury. Low-level laser therapy (LLLT) is another option for the treatment of neuropathic pain. In this study, we quantified the effects of oxytocin or LLLT alone and the combination of oxytocin and LLLT on cortical excitation induced by electrical stimulation of the dental pulp using optical imaging with a voltage-sensitive dye in the neuropathic pain model with partial ligation of the infraorbital nerve (pl-ION). We applied oxytocin (OXT, 0.5 µmol) to the rat once on the day of pl-ION locally to the injured nerve. LLLT using a diode laser (810 nm, 0.1 W, 500 s, continuous mode) was performed daily via the skin to the injured nerve from the day of pl-ION to 2 days after pl-ION. Cortical responses to electrical stimulation of the mandibular molar pulp under urethane anesthesia were recorded 3 days after pl-ION. Both the amplitude and area of excitation in the primary and secondary somatosensory and insular cortices in pl-ION rats were larger than those in sham rats. The larger amplitude of cortical excitation caused by pl-ION was suppressed by OXT or LLLT. The expanded area of cortical excitation caused by pl-ION was suppressed by OXT with LLLT but not by OXT or LLLT alone. These results suggest that the combined application of OXT and LLLT is effective in relieving the neuropathic pain induced by trigeminal nerve injury.

Seizure duration may increase thyroid-stimulating hormone levels in children experiencing a seizure.

OBJECTIVE: Variations in hormone levels are a direct effect of epileptic discharges in both animals and humans, and seizure can affect the hypothalamus-pituitary-thyroid axis. The purpose of this study was to determine which parameters could affect the alternation of thyroid hormones in children experiencing seizure. METHODS: We retrospectively reviewed the medical records of 181 pediatric patients with seizure and compared three thyroid hormones (serum thyroid-stimulating hormone [TSH], free thyroxine [fT4], and triiodothyronine [T3]) between initial (admission to hospital) and follow-up (2 weeks later) testing. RESULTS: Multivariable logistic regression models were used to determine which six parameters (gender, age, seizure accompanying with fever, seizure type, seizure duration, and anti-epileptic drug medication) could help to explain the higher initial TSH levels in pediatric seizure. Only seizure duration in patients with an increase in TSH levels was significantly longer compared with patients with normal TSH at the time of initial testing. CONCLUSION: Neuronal excitability by seizure can cause thyroid hormonal changes, which likely reflects changes in hypothalamic function.

Stress experience and hormone feedback tune distinct components of hypothalamic CRH neuron activity.

Stress leaves a lasting impression on an organism and reshapes future responses. However, the influence of past experience and stress hormones on the activity of neural stress circuits remains unclear. Hypothalamic corticotropin-releasing hormone (CRH) neurons orchestrate behavioral and endocrine responses to stress and are themselves highly sensitive to corticosteroid (CORT) stress hormones. Here, using in vivo optical recordings, we find that CRH neurons are rapidly activated in response to stress. CRH neuron activity robustly habituates to repeated presentations of the same, but not novel stressors. CORT feedback has little effect on CRH neuron responses to acute stress, or on habituation to repeated stressors. Rather, CORT preferentially inhibits tonic CRH neuron activity in the absence of stress stimuli. These findings reveal how stress experience and stress hormones modulate distinct components of CRH neuronal activity to mediate stress-induced adaptations.

TMS excitability study in essential tremor: Absence of gabaergic changes assessed by silent period recordings.

BACKGROUND: Essential tremor (ET) is thought to emerge from activity in a distributed cerebello-thalamo-cortical network. It has been proposed that the network goes into oscillation because of abnormal GABAergic inhibitory transmission. OBJECTIVE: To test this idea by investigating GABAergic circuitry in motor cortex using transcranial magnetic stimulation (TMS). METHODS: Motor cortex excitability was examined using TMS in 21 patients with essential tremor and in 20 control subjects. Resting and active motor threshold (RMT, AMT) and input-output curves examined corticospinal excitability. Contralateral silent period (cSP) at a different range of stimulation intensities, and the ipsilateral silent period (iSP) using a stimulus intensity of 150% RMT were used as measures of GABAergic function. RESULTS: RMT and AMT were significantly lower in patients than controls and patients had a steeper I/O curve. However, there were no significant differences in either cSP at different intensities or in iSP. CONCLUSION: We found no evidence in favour of the GABA hypothesis in ET.