While three decades of intensive cortical electrophysiology using a variety of sustained visual stimuli has made a significant contribution to many aspects of visual function, it has not supported the existence of intracortical circuit operations in cortical processing. This study investigated cortical processing by a comparison of the response of primary visual cortical neurones to transient electrical and strobe-flash stimulation. Experiments were performed on 74 anaesthetised Long Evans rats. Standard stereotaxic and extracellular electrophysiological techniques were employed. Continuous (on-line) raster plots and peri-stimulus time histograms (PSTHs) of the extracellular spikes from 81 visual cortical and 55 lateral geniculate nucleus (LGN) neurones were compiled. The strobe-flash stimuli (0.05 ms) were applied to the contralateral eye while the monopolar or bipolar electrical stimuli (0.2 ms, 80-400 μA) were applied to the ipsilateral LGN. 60 of the 81 (74%) tested cortical units were found to be responsive to visual stimuli. A distinct and consistent difference in the cortical response to the two types of transient stimuli was found: (a) Electrical stimulation evoked a prolonged period (197 ± 61 ms) of inhibition in all cortical neurones tested (n=20). This was the case even in those cortical units that were completely unresponsive to visual stimulation. The protracted inhibition was usually followed by a 100-200 ms phase of rebound excitation. (b) Flash stimulation evoked a prominent excitatory discharge (5-30 ms duration) after a latency of 30-60 ms from the onset of the stimulus (n = 59). This was followed by either moderate inhibition or return to a firing rate similar to control activity, for a maximum of 40 ms. Thereafter, cortical neurones showed a sustained increased level of activity with superimposed secondary excitatory phases. The duration of this late re-excitatory phase was 200-300 ms. In 17 of 20 (85%) tested units, the temporal profile of the cortical response to flash stimulation was modulated by small changes in the level of background illumination. In 16 of the 17 units, this sensitivity was reflected primarily as an emergence of a brief secondary inhibitory phase at the lowest level of background illumination (0 lux). Only 1 of the 17 cortical units displayed a flash-evoked primary inhibitory phase at O lux. We explored the possibility that neurones in the lateral geniculate nucleus (LGN) of the thalamus were responsible for the late phase of cortical reexcitation. 49 of the 55 (89%) LGN neurones could be classified as either of the "ON type" i.e. excited by visual stimuli, or the "OFF type" i.e. inhibited by visual stimuli. The response of ON-like LGN neurones to strobe-flash stimulation of the contralateral eye was characterised by a primary excitatory or early discharge (ED) phase after a latency of 25-40 ms. Thereafter, a 200- 400 ms period of inhibition was observed. In 57% of the sample, a rebound excitatory or late discharge (LD) phase completed the response. OFF-like LGN neurones were inhibited by the strobe-flash stimuli after a latency of 30- 35 ms. This flash-evoked inhibition was maintained for 200-400 ms. The sensitivity of the flash-evoked LGN response to the level of background illumination was tested in 11 ON-like and 10 OFF-like neurones. No sustained secondary excitatory events, as observed in visual cortical neurones, were found in any of the ON- and OFF-like LGN neurones, irrespective of the level of background illumination. In conclusion, the data show that the late re-excitatory phase evoked in cortical neurones upon strobe-flash stimulation, is not due to sustained LGN (thalamic) input. Rather, it suggests that these re-excitatory phases are due to intracortical processing of the transient stimuli. These findings emphasize the independent role of the cortex in computing the response to visual stimuli, and cast doubt on traditional theories that have emphasised the role of the thalamus in shaping cortical responses. The difference in the flash and electrically evoked cortical response suggests that even though substantial inhibition is available to the cortex, only a small fraction of this inhibitory capacity is utilised during natural stimulation.

No description available.

Dysfunction of the visual cortex is implicated in psychosis and recently, the extrastriate visual cortex (V5/MT) has been causally linked to visual hallucinations through lesion network mapping. Transcranial electric stimulation (tES) has been shown to improve psychotic symptoms and cognition in psychosis spectrum disorders. However, few investigations have used novel approaches, such as high definition tES (HD-tES) to target specific brain circuits. Previously, we showed that stimulation delivered to V5/MT using HD-tDCS (direct current) reduced Positive and Negative Syndrome Scale (PANSS) general symptoms in the short-term (5 days), while HD-tACS (alternating current) improved general symptoms and functioning in the long-term (30 days). Here, we aim to determine if HD-tES to V5/MT has altering effects on cognition and self-reported symptoms of psychosis, and to investigate the differences between self-reported and clinician-reported symptoms. A pilot open label study with a within-subjects, single blind, crossover design was conducted in order to characterize the efficacy of cathodal HD-tDCS and 2Hz delta HD-tACS for psychosis treatment. Enrolled patients received 20 mins of HD-tES twice daily for 5 consecutive days applied bilaterally to V5/MT with a washout between conditions. Assessments were performed at baseline, day 5, and day 30. HD-tACS treatment was found to improve cognition on Digit Sequencing, Tower of London, Semantic Fluency, and “S” Letter Fluency tasks as measured by brief assessment of cognition in schizophrenia (BACS) as well as symptoms of paranoid ideation and anger/hostility as measured by the symptom checklist 90 (SC-90) 1 month after treatment. HD-tDCS treatment yielded significant improvement on “F” Letter Fluency as measured by BACS and did not yield any significant improvement on SC-90 symptoms. Lastly, correlations between SC-90 and PANSS described a distinct relationship between the two scales and their measures of psychiatric morbidity. Ultimately, delta wave tACS may be able to improve cognition and certain symptoms of psychosis by altering cortico-cortico communication between relevant brain structures. Future large-scale investigations are needed to further solidify these results. / 2026-03-04T00:00:00Z

In summary, the biomechanical stimulations can augment osteotendinous healing processes by facilitating better fibrocartilagious transitional zone regeneration as well as the restoration of proprioceptions, and the early application showed the more beneficial effects. However, further experimental and clinical studies are still needed to explore the optimal timing, intensity, frequency, and duration of the proposed postoperative biomechanical stimulation protocols. / LIPUS is a "non-contact" biomechanical stimulation, which can provide a direct mechanical stimulation through cavitation and acoustic microstreaming effects to improve tissue healing in a less-than-rigid biomechanical environment. So the mechanical stimulation induced from LIPUS could be applied immediately after surgery without worrying about the mechanical strain exceed the structural property at the osteotendinous healing interface in the early phase of repair. In this part of study, we also examined the effects of the regime of biomechanical stimulations applying immediately after repair on the osteotendinous healing interface. By using the same healing junction model, forty-two female New Zealand white rabbits were randomly divided into two groups; daily mechanical stimulation was applied immediately after surgery lasting up to post-operative 12 weeks on the healing interface in the treatment group. The regime of mechanical stimulations included by LIPUS was 20 minutes, 5 days per week for 4 weeks, followed by cyclic mechanical stimulation generated from quadriceps muscles induced by FES for 8 weeks. Results showed that early application of biomechanical stimulations on the osteotendinous healing interface were significantly better radiologically, histologically and biomechanically than that of not any or later application of the biomechanical stimulations during the osteotendinous healing processes when assessing at the same healing time point. In addition, the early application of biomechanical stimulations showed the better functional recovery in terms of the restoration of the proprioceptions, which an increased numbers of sensory nerve endings labeled by calcitonin gene-relate peptide (CGRP) was detected in the whole osteotendinous healing complex. / Sports or trauma injuries around osteotendinous junctions are common; treatments usually require surgical reattachment of the involved tendon to bone. Restoration of osteotendinous junction after repair is slow and difficult due to regenerating the intermitted fibrocartilage zone to connect two different characteristic tissues, tendon to bone. Although the factors influencing fibrocartilage zone regeneration and remodeling during osteotendinous repair are poorly understood, however, is believed that the mechanical environment plays an important role in such healing process. In present study, the effects of mechanical stimulation on osteotendinous healing process were examined, in the way of mechanical stimulations induced by biophysical stimulations, surface functional electric stimulation (FES) and low intensity pulsed ultrasound (LIPUS), applying on the patellar tendon to patellar bone healing interface in an established partial patellectomy model in rabbits. / The mechanotransductive stimulation linked to the transmission of forces across osteotendinous junction can be generated from its muscle contraction induced by FES. In the partial patellectomy model, thirty-five female New Zealand white rabbits were randomly divided into two groups with initial immobilization for 6 weeks, daily FES was applied to quadriceps muscles for 30 minutes, 5 days per week for 6 weeks in treatment group and compared with non-treatment control group at postoperative week 6, 12 and 18, radiologically, histologically and biomechanically. Results showed that FES-induced cyclic mechanical stimulation significantly increased new bone formation and its bone mineral density. An elevated expression of tenascin C and TGFbeta1; an increased proteoglycant stainability; mature fibrocartilage zone formation with better resumptions of biomechanical properties also observed on the osteotendinous healing interface, indicating that the post-operative programmed cyclic mechanical stimulation generated from its muscle contraction has beneficial effects on osteotendinous healing processes by facilitating the fibrocartilagious transitional zone regeneration. / by Wang Wen. / Advisers: Kai Ming Chan; Ling Qin. / Source: Dissertation Abstracts International, Volume: 68-03, Section: B, page: 1550. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2006. / Includes bibliographical references (p. 159-175). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.

Thesis: M.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1981 / Includes bibliographical references. / by John Harvey Serocki. / M.S. / M.S. Massachusetts Institute of Technology, Department of Mechanical Engineering

This thesis focuses on assistive and rehabilitation technology for restoring the function of the hand. It presents three different approaches to assistive technology: one in the form of an orthosis, one in the form of a brain-computer interface combined with functional electrical stimulation and finally one totally aiming at rehabilitating the nervous system by restoring brain function using the concept of neuroplasticity. The thesis also includes an epidemiological study based on statistics from the Swedish Hospital Discharge Register and a review on different methods for assessment of hand function. A novel invention of an orthosis in form of a light weight glove, the SEM (Soft Extra Muscle) glove, is introduced and described in detail. The SEM glove is constructed for improving the grasping capability of a human independently of the particular task being performed. A key feature is that a controlling and strengthening effect is achieved without the need for an external mechanical structure in the form of an exoskeleton. The glove is activated by input from tactile sensors in its fingertips and palm. The sensors react when the applied force is larger than 0.2 N and feed a microcontroller of DC motors. These pull lines, which are attached to the fingers of the glove and thus work as artificial tendons. A clinical study on the feasibility of the SEM glove to improve hand function on a group of patients with varying degree of disability has been made. Assessments included passive and active range of finger motion, flexor muscle strength according to the Medical Research Council (MRC) 0-5 scale, grip strength using the Grippit hand dynamometer, fine motor skills according to the Nine Hole Peg test and hand function in common activities by use of the Sollerman test. Participants rated the potential benefit on a Visual Analogue Scale. A prototype for a system for combining BCI (Brain-Computer Interface) and FES (Functional Electrical Stimulation) is described. The system is intended to be used during the first period of recovery from a TBI (Traumatic Brain Injury) or stroke that have led to paresis in the hand, before deciding on a permanent system, thus allowing the patients to get a quick start on the motor relearning. The system contains EEG recording electrodes, a control unit and a power unit. Initially the patients will practice controlling the movement of a robotic hand and then move on to controlling pulses being sent to stimulus electrodes placed on the paretic muscle. An innovative electrophysiological device for rehabilitation of brain lesions is presented, consisting of a portable headset with electrodes on both sides adapted on the localization of treatment area. The purpose is to receive the outgoing signal from the healthy side of the brain and transfer that signal to the injured and surrounding area of the remote side, thereby having the potential to facilitate the reactivation of the injured brain tissue. The device consists of a control unit as well as a power unit to activate the circuit electronics for amplifying, filtering, AD-converting, multiplexing and switching the outgoing electric signals to the most optimal ingoing signal for treatment of the injured and surrounding area. / <p>QC 20130403</p>

Avaliamos a influência da imobilização, remobilização livre, remobilização com alongamento passivo manual, remobilização com estimulação elétrica neuromuscular (EENM) e remobilização com estimulação elétrica e alongamento passivo associados sobre algumas propriedades mecânicas do músculo gastrocnêmio de ratas. Foram utilizadas 60 ratas albinas da variedade Wistar e divididas em 6 grupos experimentais. Um grupo foi utilizado como controle. Cinco grupos tiveram o membro posterior direito imobilizado por 14 dias consecutivos. Destes 5 grupos um foi submetido à morte logo após o período de imobilização, um foi liberado da imobilização permanecendo em gaiolas plásticas por 10 dias, outro foi submetido a técnica de alongamento passivo manual por 10 dias consecutivos, outro foi submetido a EENM por 10 dias consecutivos e o último foi submetido a EENM somado ao alongamento passivo manual por 10 dias consecutivos. Após os períodos de intervenção os animais foram mortos e em seguida realizados os ensaios mecânicos de tração longitudinal dos músculos. As propriedades mecânicas avaliadas foram a carga e alongamento no limite de proporcionalidade e no limite máximo, a rigidez e a capacidade de absorver energia na fase elástica (resiliência) do músculo, obtidas a partir das curvas carga versus alongamento. Observamos que a imobilização provocou redução significativa nos valores das propriedades mecânicas avaliadas no músculo gastrocnêmio. A remobilização por alongamento passivo manual devolveu ao músculo as propriedades de alongamento no limite de proporcionalidade, rigidez e resiliência a padrões controle, entretanto não foi capaz de restabelecer as propriedades de carga no limite de proporcionalidade, carga e alongamento no limite máximo. A remobilização constituída por EENM restabeleceu todas as propriedades estudadas a padrões controle. A remobilização por estimulação elétrica somada ao alongamento passivo restabeleceu as propriedades mecânicas de alongamento no limite máximo e de proporcionalidade e rigidez, no entanto não foi capaz de devolver ao músculo suas propriedades carga no limite máximo, carga no limite de proporcionalidade e resiliência. A remobilização livre não foi capaz de restabelecer nenhuma das propriedades a padrões controle / We evaluated the influence of immobilization, free remobilization, remobilization with manual passive stretching, remobilization with neuromuscular electric stimulation (NMES) and remobilization with electric stimulation and passive stretching associated upon some mechanical properties of the gastrocnemius muscle of female rats. We used sixty female albinic rats of the variety Wistar and divided them in 6 experimental groups. One of these groups was used as control. The animals of the five other groups had their right hind immobilized for 14 consecutive days. From the five groups, one was submitted to death right after the immobilization period, a second was set free from the immobilization remaining in plastic cages for 10 days, a third was submitted to the manual passive stretching technique for 10 consecutive days, a fourth was submitted to NMES for 10 consecutive days and the last one was submitted to NMES and manual passive stretching for 10 consecutive days. After the intervention periods, the animals were submitted to death and afterwards the mechanical tests of longitudinal traction of the muscles were done. The mechanical properties evaluated were the load and the stretching in the limit of proportionality and in the maximum limit, the stiffness and the capacity to absorb energy in the elastic phase (resilience) of the muscle, obtained based on the curves load versus stretching. We observed that the immobilization has provoked significant reduction of the values of the mechanical properties evaluated in the gastrocnemius muscle. The remobilization by the manual passive stretching gave back to the muscle the mechanical properties of stretching in the limit of proportionality, stiffness and resilience like the standard ones of the control group, but it was not capable of reestablishing the properties of load in the limit of proportionality, load and stretching in the maximum limit. The remobilization done by the NMES reestablished all of the properties studied like ones of the control group. The remobilization by electric stimulation and passive stretching reestablished the mechanical properties in the maximum limit and in the proportionality and stiffness, although it was not capable of giving back to the muscle its properties of load in the maximum limit, load in the limit of proportionality and resilience. The free remobilization was not capable of reestablish any of the properties like the ones of the control group

A mortalidade em pessoas com lesão medular é três vezes maior que na população em geral. As doenças cardiovasculares são umas das mais relevantes na lista de doenças que as acometem, ocorrendo cada vez mais precocemente. Dentre os fatores de risco para doenças cardiovasculares a inatividade física é um importante fator modificável para esta população. O grupo de tetraplégicos é o que demonstra maior comprometimento físico. Devido ao menor recrutamento muscular voluntário, as possibilidades terapêuticas para o condicionamento cardiorrespiratório são limitadas. Entre as alternativas terapêuticas está o cicloergometro com estimulação elétrica funcional computadorizada - CFES. Este estudo teve como objetivo comparar os efeitos do condicionamento dos músculos estimulados por corrente elétrica em pacientes tetraplégicos na frequência de treinamento de uma (1) vez por semana e de três (3) vezes por semana, durante seis meses de treinamento. Quatorze indivíduos adultos, homens, tetraplégicos, divididos aleatoriamente em dois grupos, realizaram CFES com as diferentes frequências de treinamento. Foi avaliada a variável trabalho desenvolvida durante cada sessão. A análise estatística foi realizada através de inferência bayesiana. As observações realizadas no presente estudo indicam que o desempenho musculoesquelético do grupo de treinamento de três vezes por semana pode ser melhor que o de uma vez por semana. A variabilidade de desempenho encontrada em estudos longitudinais sugere protocolos de intervenção mais abrangentes. / Mortality in people with spinal cord injury is three times higher than in the overall population. Cardiovascular diseases are the most prevalent one affecting these individuals, occurring increasingly at an earlier age. With the risk factors for cardiovascular diseases, physical inactivity is an important and modifiable aspect for this population. The quadriplegic group is the one showing the larger physical impairment. Due to the lower volunteer muscle recruitment, therapeutic possibilities for cardiorespiratory conditioning are limited. Among the therapeutic alternatives is the computadorized functional electric stimulation - CFES. This study aimed to compare the effects of ergometric training over the conditioning of the muscles of quadriplegic patients, stimulated by electric current, once and three times a week, for six months of training. Fourteen quadriplegic male adults were divided randomly into two groups, performing the training in the different treatment frequencies. Mechanical work varialble was assessed throughout each treatment session. The statistical analysis was performed by Bayesian Inference. The study\'s observations indicate that the musculoskeletal performance of those in the three times a week treatment may be better than of those in the lower frequency group. The variability of the performance found with longitudinal studies suggests broader intervention protocols.

Fundamento: A fraqueza muscular periférica possui associação direta com a mortalidade intra-hospitalar em pacientes internados em unidades de terapia intensiva (UTIs). Dessa forma, a estimulação elétrica neuromuscular (EENM) tem sido indicada como uma forma de mobilização precoce para preservação ou aumento da massa e força muscular nesses indivíduos. Objetivo: O objetivo deste estudo foi revisar sistematicamente os efeitos da EENM comparada com cuidados usuais ou EENM placebo sobre a espessura muscular em pacientes críticos internados em UTIs. Métodos: Foi realizada uma busca nas bases Cochrane CENTRAL, MEDLINE, Lilacs, PEDro, e busca manual em referências de estudos publicados até maio de 2015. Foram incluídos ensaios clínicos randomizados (ECRs) que compararam EENM vs. cuidados usuais ou EENM placebo sobre a espessura muscular do músculo reto femoral avaliada por meio de ultrassonografia em pacientes críticos internados na UTIs. Os estudos foram analisados separadamente em relação ao tempo de início da EENM: precoce (início da EENM inferior a sete dias de internação) e tardio (início da EENM superior a 14 dias de internação). Resultados: Foram identificados 1.719 artigos, sendo incluídos dois ECRs. Na aplicação com início precoce, foi observado que a EENM preserva a espessura muscular comparado com cuidados usuais, porém sem diferença significativa (0,09 mm; IC95% -0,08 a 0,25). Tardiamente, apenas um estudo avaliou esse efeito, sendo observado que a espessura aumentou significativamente com EENM (p=0,036), permanecendo inalterada no grupo controle (p=0,162), sendo superior ao grupo controle (p=0,013). Conclusões: A aplicação precoce da EENM não alterou significativamente a espessura muscular do reto femoral em pacientes críticos internados em UTIs. Porém, a aplicação com início tardio, aumentou significativamente essa variável. No entanto, devido à escassez de pesquisas com a análise desse desfecho específico, novos estudos são necessários para confirmação dos achados. / Background: Peripheral muscle weakness has direct association with intra-hospital mortality in patients hospitalized in intensive care units (ICUs). Thus, neuromuscular electrical stimulation (NMES) has been indicated as a form of early mobilization to preserve or increase muscle mass and strength in these patients. Objective: The objective of this study was to systematically review the effects of NMES compared with usual care or placebo NMES on muscle thickness in hospitalized critically ill patients in ICUs. Methods: A search of the Cochrane CENTRAL, MEDLINE, Lilacs, PEDro, and manual search of published studies on references by May 2015 was performed. Included were randomized controlled trials (RCTs) that compared NMES vs. usual care or placebo NMES on the muscular thickness of the rectus femoris muscle assessed by means of ultrasound in critically ill patients hospitalized in ICU. The studies were analyzed separately in relation to start of the NMES: early (early NMES less than seven days of hospitalization) and late (early NMES than 14 days of hospitalization). Results: Was identified 1719 articles, which included two RCTs. In application with early start, it was observed that NMES preserves muscle thickness compared with usual care, but with no significant difference (0.09 mm, 95% CI -0.08 to 0.25). Belatedly, only one study has evaluated this effect being noted that the thickness increased significantly with NMES (p = 0.036) and remained unchanged in the control group (p = 0.162), higher than the control group (p = 0.013). Conclusions: Early application of NMES does not has significantly changed the thickness of the rectus femoris muscle in critical patients hospitalized in ICUs. However, the application with late onset, significantly increased this variable. However, due to scarcity of research with the analysis of this specific outcome, further studies are needed to confirm the findings.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1981. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Vita. / Bibliography: leaves 109-112. / by Christopher Rose. / M.S.