Este trabalho é apoiado por uma Bolsa discovery para BDC do Conselho de Ciências Naturais e Engenharia do Canadá (NSERC; RGPIN 311680) e bolsa operacional para BDC dos Institutos Canadenses de Pesquisa em Saúde (CIHR; MOP-93796). A RAK foi apoiada por uma bolsa de pós-graduação em Ontário, e a ALC foi apoiada por uma bolsa NSERC CREATE. O aparelho experimental descrito neste manuscrito foi apoiado pela Fundação Canadá para a Inovação. O apoio adicional veio do Canada First Research Excellence Fund (BrainsCAN).

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	<li>Veerman, M. M., Brenner, E., Smeets, J. B. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+latency+for+correcting+a+movement+depends+on+the+visual+attribute+that+defines+the+target.">The latency for correcting a movement depends on the visual attribute that defines the target.</a> Experimental Brain Research. 187 (2), 219-228 (2008).</li><li>Soechting, J. F., Lacquaniti, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Modification+of+trajectory+of+a+pointing+movement+in+response+to+a+change+in+target+location.">Modification of trajectory of a pointing movement in response to a change in target location.</a> Journal of Neurophysiology. 49 (2), 548-564 (1983).</li><li>Day, B. L., Lyon, I. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Voluntary+modification+of+automatic+arm+movements+evoked+by+motion+of+a+visual+target.">Voluntary modification of automatic arm movements evoked by motion of a visual target.</a> Experimental Brain Research. 130 (2), 159-168 (2000).</li><li>Gaveau, V., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Automatic+online+control+of+motor+adjustments+in+reaching+and+grasping.">Automatic online control of motor adjustments in reaching and grasping.</a> Neuropsychologia. 55 (1), 25-40 (2014).</li><li>Day, B. L., Brown, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Evidence+for+subcortical+involvement+in+the+visual+control+of+human+reaching.">Evidence for subcortical involvement in the visual control of human reaching.</a> Brain A Journal of Neurology. 124, 1832-1840 (2001).</li><li>Pruszynski, A. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Stimulus-locked+responses+on+human+arm+muscles+reveal+a+rapid+neural+pathway+linking+visual+input+to+arm+motor+output.">Stimulus-locked responses on human arm muscles reveal a rapid neural pathway linking visual input to arm motor output.</a> European Journal of Neuroscience. 32 (6), 1049-1057 (2010).</li><li>Corneil, B. D., Olivier, E., Munoz, D. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Visual+responses+on+neck+muscles+reveal+selective+gating+that+prevents+express+saccades.">Visual responses on neck muscles reveal selective gating that prevents express saccades.</a> Neuron. 42 (5), 831-841 (2004).</li><li>Wood, D. K., Gu, C., Corneil, B. D., Gribble, P. L., Goodale, M. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transient+visual+responses+reset+the+phase+of+low-frequency+oscillations+in+the+skeletomotor+periphery.">Transient visual responses reset the phase of low-frequency oscillations in the skeletomotor periphery.</a> European Journal of Neuroscience. 42 (3), 1919-1932 (2015).</li><li>Gu, C., Wood, D. K., Gribble, P. L., Corneil, B. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+Trial-by-Trial+Window+into+Sensorimotor+Transformations+in+the+Human+Motor+Periphery.">A Trial-by-Trial Window into Sensorimotor Transformations in the Human Motor Periphery.</a> Journal of Neuroscience. 36 (31), 8273-8282 (2016).</li><li>Kozak, R. A., Kreyenmeier, P., Gu, C., Johnston, K., Corneil, B. 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C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cross-species+comparison+of+anticipatory+and+stimulus-driven+neck+muscle+activity+well+before+saccadic+gaze+shifts+in+humans+and+nonhuman+primates.">Cross-species comparison of anticipatory and stimulus-driven neck muscle activity well before saccadic gaze shifts in humans and nonhuman primates.</a> Journal of Neurophysiology. 114 (2), 902-913 (2015).</li><li>Franklin, D. W., Reichenbach, A., Franklin, S., Diedrichsen, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Temporal+evolution+of+spatial+computations+for+visuomotor+control.">Temporal evolution of spatial computations for visuomotor control.</a> Journal of Neuroscience. 36 (8), 2329-2341 (2016).</li><li>Krekelberg, B., Vatakis, A., Kourtzi, Z. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Implied+motion+from+form+in+the+human+visual+cortex.">Implied motion from form in the human visual cortex.</a> Journal of Neurophysiology. 94 (6), 4373-4386 (2005).</li><li>Gribble, P. 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Os autores não têm nada a revelar.

Os seres humanos têm uma capacidade notável, quando necessário, de gerar ações rápidas e visualmente guiadas em latências que se aproximam de atrasos mínimos de condução diferentes e diferentes. Descrevemos anteriormente as respostas bloqueadas por estímulo (SLRs) no membro superior como uma nova medida para respostas rápidas de visuomotor6,9,10. Embora benéfico em fornecer um benchmark trial-by-trial para o primeir...

Quando notamos uma mensagem em nosso celular, somos solicitados a realizar um alcance visualmente guiado para pegar nosso telefone e ler a mensagem. Características visuais como a forma e o tamanho do telefone são transformados em comandos motores, permitindo-nos alcançar com sucesso o objetivo. Tais transformações visuomotor podem ser estudadas em condições laboratoriais, que permitem um alto grau de controle. No entanto, há cenários em que o tempo de resposta é importante, por exemplo, pegar o telefone se ele cair. Estudos laboratoriais de comportamentos rápidos de visuomotor muitas vezes dependem de paradigmas de alvo deslocados onde os movimentos em andamento são modificados no meio do voo após alguma mudança na posição alvo (por exemplo, ver ref.1,2). Embora tais correções on-line possam ocorrer em <150 ms3, é difícil determinar o tempo exato da saída rápida do visuomotor usando apenas cinemática devido às características de filtragem de baixo passe do braço, e porque a saída rápida do visuomotor substitui um movimento já no meio do voo. Tais complicações levam à incerteza sobre os substratos subjacentes às respostas rápidas do visuomotor (ver ref.4 para revisão). Alguns estudos sugerem que estruturas subcorticais como o coloiculus superior, em vez de áreas cortical fronto-parietal, podem iniciar correções on-line5.
Essa incerteza em relação aos substratos neurais subjacentes pode ser devido, pelo menos em parte, à falta de um biomarcador confiável para a saída do sistema visuomotor rápido. Recentemente, descrevemos uma medida de respostas rápidas de visuomotor que podem ser geradas a partir de posturas estáticas e registradas via eletromografia (EMG). As respostas bloqueadas por estímulo (SLRs) são rajadas de tempo travadas da atividade EMG que precedem o movimento voluntário6,7, evoluindo consistentemente ~100 ms após o início do estímulo. Como o nome indica, as SLRs são evocadas pelo início do estímulo, persistindo mesmo que um eventual movimento seja retido8 ou se mova na direção oposta9. Além disso, os SLRs evocados pelo deslocamento de destino em um paradigma dinâmico estão associados a correções on-line de latência mais curtas10. Assim, os SLRs fornecem uma medida objetiva para estudar sistematicamente a saída de um sistema visuomotor rápido envolvido em RTs de latência curta, pois eles podem ser gerados a partir de uma postura estática e analisados a partir de outros sinais EMG não relacionados à fase inicial da resposta rápida do visuomotor.
O objetivo do presente estudo é apresentar um paradigma de alcance visualmente guiado que provoque robustamente as SLRs. Estudos anteriores que investigam o SLR relataram menos de 100% de taxas de detecção entre os participantes, mesmo quando se utilizava gravações intramusculares mais invasivas6,8,9. Baixas taxas de detecção e dependência de gravações invasivas limitam a utilidade das medidas de SLR em investigações futuras sobre o sistema de visuomotor rápido em doenças ou em toda a vida útil. Embora alguns sujeitos possam simplesmente não expressar SLRs, os estímulos e paradigmas comportamentais usados anteriormente podem não ter sido ideais para evocar o SLR. Relatórios anteriores de SLRs têm normalmente usado paradigmas em que os participantes geram alcances visualmente guiados em direção à estática, aparecendo repentinamente as metas6,9. No entanto, um sistema visuomotor rápido é o mais provável em cenários onde é preciso interagir rapidamente com um objeto em queda ou voador, levando-se a se perguntar se mover-se em vez de estímulos estáticos pode evocar melhor SLRs. Portanto, adaptamos um paradigma de alvo móvel usado para estudar os movimentos oculares11, e combinamos com uma tarefa de alcance pró/anti visualmente guiada usada para examinar o SLR9. Quando comparados aos resultados de paradigmas utilizados anteriormente6,8,9, verificou-se que as SLRs no paradigma alvo emergente evoluíram mais cedo, atingiram magnitudes mais elevadas e foram mais prevalentes em nossa amostra participante. Em geral, o paradigma alvo emergente promove a expressão de respostas rápidas de visuomotor a tal ponto que medidas objetivas de EMG podem ser feitas de forma confiável com registros superficiais, potencializando o estudo dentro das populações clínicas e em toda a vida útil. Além disso, o paradigma de alvo emergente pode ser modificado de muitas maneiras diferentes, promovendo investigações mais aprofundadas sobre os fatores sensoriais, cognitivos e motores que promovem ou modificam respostas rápidas do visuomotor.

<table>
	<tbody>
		<tr>
			<td>Bagnoli-8 Desktop Surface EMG System</td>
			<td>Delsys Inc.</td>
			<td></td>
			<td>Another reaching apparatus may be used</td>
		</tr>
		<tr>
			<td>Kinarm End-Point Robot</td>
			<td>Kinarm, Kingston, Ontario, Canada</td>
			<td></td>
			<td>Another reaching apparatus may be used</td>
		</tr>
		<tr>
			<td>MATLAB (version R2016a) Stateflow and Simulink applications</td>
			<td>The MathWorks, Inc., Natick, Massachusetts, United States</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>PROPixx projector</td>
			<td>VPIXX Saint-Bruno, QC, Canada</td>
			<td></td>
			<td>This is a custom built addon for the Kinarm. Other displays may be used.</td>
		</tr>
		<tr>
			<td></td>
			<td></td>
			<td></td>
			<td>Resolution: 1920 x 1080. Standard viewing monitors may also be used.</td>
		</tr>
	</tbody>
</table>

an emerging target paradigm to evoke fast visuomotor responses on human upper limb muscles

Para alcançar um objeto visto, a informação visual precisa ser transformada em comandos motores. Informações visuais como a cor, forma e tamanho do objeto são processadas e integradas em inúmeras áreas cerebrais, em última análise retransmitidas para a periferia motora. Em alguns casos, uma reação é necessária o mais rápido possível. Essas transformações rápidas de visuomotor, e seus substratos neurológicos subjacentes, são mal compreendidas em humanos, pois não têm um biomarcador confiável. As respostas bloqueadas por estímulo (SLRs) são rajadas de latência curtas (<100 ms) de atividade eletromiográfica (EMG), representando a primeira onda de recrutamento muscular influenciada pela apresentação de estímulo visual. Os SLRs fornecem uma saída quantificável de transformações rápidas de visuomotor, mas as SLRs não têm sido consistentemente observadas em todos os sujeitos em estudos anteriores. Aqui descrevemos um novo paradigma comportamental com o surgimento repentino de um alvo em movimento abaixo de um obstáculo que evoca consistentemente SLRs robustos. Os participantes humanos gerados visualmente guiados alcançam alcances visualmente guiados em direção ou longe do alvo emergente usando um manipulador robótico enquanto eletrodos superficiais registravam a atividade EMG do músculo principal peitoral. Em comparação com estudos anteriores que investigaram as SLRs utilizando estímulos estáticos, as SLRs evocadas com esse paradigma alvo emergente foram maiores, evoluíram anteriormente e estiveram presentes em todos os participantes. Os tempos de reação de alcance (RTs) também foram acelerados no paradigma alvo emergente. Esse paradigma oferece inúmeras oportunidades de modificação que poderiam permitir um estudo sistemático do impacto de várias manipulações sensoriais, cognitivas e motoras em respostas rápidas de visuomotor. No geral, nossos resultados demonstram que um paradigma alvo emergente é capaz de evocar de forma consistente e robusta a atividade dentro de um sistema visuomotor rápido.

As respostas bloqueadas de estímulo (SLRs) são breves rajadas de tempo de atividade muscular travadas ao início do estímulo que evolui bem antes da maior onda de recrutamento muscular associada ao início do movimento. A natureza bloqueada do tempo do SLR produziu uma "banda" de atividade muscular visível a ~100 ms ao visualizar todos os ensaios classificados para o tempo de reação (RT) (Figura 1a, destacado por caixas cinza). Como mostrado na Figura 1a,a...

Watch this Scientific Journal Video about An Emerging Target Paradigm to Evoke Fast Visuomotor Responses on Human Upper Limb Muscles at JoVE.com

An Emerging Target Paradigm to Evoke Fast Visuomotor Responses on Human Upper Limb Muscles

Apresentado aqui é um paradigma comportamental que provoca respostas robustas e rápidas de visuomotor nos músculos dos membros superiores humanos durante alcances visualmente guiados.

Um paradigma de alvo emergente para evocar respostas rápidas do visuomotor sobre músculos dos membros superiores humanos

To reach towards a seen object, visual information has to be transformed into motor commands. Visual information such as the object&#8217;s color, shape, ...

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Neuroscience

4.2K visualizações.  Western University. Apresentado aqui é um paradigma comportamental que provoca respostas robustas e rápidas de visuomotor nos músculos dos membros superiores humanos durante alcances visualmente guiados.

Vídeo: An Emerging Target Paradigm to Evoke Fast Visuomotor Responses on Human Upper Limb Muscles

Recording Behavioral Responses to Reflection in Crayfish

Social behavior depends on sensory input from the visual, mechanical and olfactory systems. One important issue concerns the relative roles of each sensory modality in guiding behavior. The role of visual inputs has been examined by isolating visual stimuli from mechanical and chemosensory stimuli. In some studies (Bruski &amp; Dunham, 1987: Delgado-Morales et al., 2004) visual inputs have been removed with blindfolds or low light intensity, and effects of remaining sensory modalities have been elucidated. An alternative approach is to study the effects of visual inputs in the absence of any appropriate mechanical and chemosensory cues. This approach aims to identify the exclusive role of visual inputs. 
We have used two methods to provide visual stimuli to crayfish without providing chemical and mechanical cues. In one method, crayfish are videotaped in an aquarium where half of the walls are covered in mirrors to provide a reflective environment, and the other half are covered in a non-reflective (matte finish) plastic. This gives the crayfish a choice between reflective and non-reflective environments. The reflective environment provides visual cues in the form of reflected images of the crayfish as it moves throughout half of the tank; these visual cues are missing from the non-reflective half of the tank. An alternative method is to videotape the behavior of crayfish in an aquarium separated by a smaller chamber at each end, with a crayfish in one small chamber providing visual cues and an inert object in the opposite small chamber providing visual input from a non-moving, non-crayfish source. 
Our published results indicate that responses of crayfish to the reflective environment depend on socialization and dominance rank. Socialized crayfish spent more time in the reflective environment and exhibited certain behaviors more frequently there than in the non-reflective environment; isolated crayfish showed no such differences. Crayfish that were housed in same-sex pairs developed a social rank of either dominant or subordinate. Responses to reflection differed between dominant and subordinate crayfish (May &amp; Mercier, 2006; May &amp; Mercier, 2007). Dominant crayfish spent more time on the reflective side, entered reflective corners more frequently and spent more time in reflective corners compared to the non-reflective side. Subordinate crayfish walked in reverse more often on the reflective side than on the non-reflective side. Preliminary data suggest similar effects from visual cues provided by a crayfish in a small adjoining chamber (May et al., 2008).

We have developed two methods for studying effects of visual cues on behavior in the absence of tactile and chemical cues. One method involves videotaping responses of crayfish to reflective walls in an aquarium; the other examines effects of visual inputs provided by a live crayfish behind a transparent partition.

Gravação de respostas comportamentais à Reflexão em Crayfish

Social behavior depends on sensory input from the visual, mechanical and olfactory systems.  One important issue concerns the relative roles of each ...

Neurociência

Vibrodissociation of Neurons from Rodent Brain Slices to Study Synaptic Transmission and Image Presynaptic Terminals

Mechanical dissociation of neurons from the central nervous system has the advantage that presynaptic boutons remain attached to the isolated neuron of interest. This allows for examination of synaptic transmission under conditions where the extracellular and postsynaptic intracellular environments can be well controlled. A vibration-based technique without the use of proteases, known as vibrodissociation, is the most popular technique for mechanical isolation. A micropipette, with the tip fire-polished to the shape of a small ball, is placed into a brain slice made from a P1-P21 rodent. The micropipette is vibrated parallel to the slice surface and lowered through the slice thickness resulting in the liberation of isolated neurons. The isolated neurons are ready for study within a few minutes of vibrodissociation. This technique has advantages over the use of primary neuronal cultures, brain slices and enzymatically isolated neurons including: rapid production of viable, relatively mature neurons suitable for electrophysiological and imaging studies; superior control of the extracellular environment free from the influence of neighboring cells; suitability for well-controlled pharmacological experiments using rapid drug application and total cell superfusion; and improved space-clamp in whole-cell recordings relative to neurons in slice or cell culture preparations. This preparation can be used to examine synaptic physiology, pharmacology, modulation and plasticity. Real-time imaging of both pre- and postsynaptic elements in the living cells and boutons is also possible using vibrodissociated neurons. Characterization of the molecular constituents of pre- and postsynaptic elements can also be achieved with immunological and imaging-based approaches.

This report demonstrates a technique for mechanical isolation of individual viable neurons retaining attached presynaptic boutons. Vibrodissociated neurons have the advantages of rapid production, excellent pharmacological control and improved space-clamp without influence from neighboring cells. This method can be used for imaging of synaptic elements and patch-clamp recording.

Vibrodissociation de neurônios de fatias do cérebro de roedores para estudar a transmissão sináptica e Imagem Terminais pré-sináptica

Mechanical dissociation of neurons from the central nervous system has the advantage that presynaptic boutons remain attached to the isolated neuron of ...

Correlating Behavioral Responses to fMRI Signals from Human Prefrontal Cortex: Examining Cognitive Processes Using Task Analysis

The aim of this methods paper is to describe how to implement a neuroimaging technique to examine complementary brain processes engaged by two similar tasks. Participants' behavior during task performance in an fMRI scanner can then be correlated to the brain activity using the blood-oxygen-level-dependent signal. We measure behavior to be able to sort correct trials, where the subject performed the task correctly and then be able to examine the brain signals related to correct performance. Conversely, if subjects do not perform the task correctly, and these trials are included in the same analysis with the correct trials we would introduce trials that were not only for correct performance. Thus, in many cases these errors can be used themselves to then correlate brain activity to them. We describe two complementary tasks that are used in our lab to examine the brain during suppression of an automatic responses: the stroop1 and anti-saccade tasks. The emotional stroop paradigm instructs participants to either report the superimposed emotional 'word' across the affective faces or the facial 'expressions' of the face stimuli1,2. When the word and the facial expression refer to different emotions, a conflict between what must be said and what is automatically read occurs. The participant has to resolve the conflict between two simultaneously competing processes of word reading and facial expression. Our urge to read out a word leads to strong 'stimulus-response (SR)' associations; hence inhibiting these strong SR's is difficult and participants are prone to making errors. Overcoming this conflict and directing attention away from the face or the word requires the subject to inhibit bottom up processes which typically directs attention to the more salient stimulus. Similarly, in the anti-saccade task3,4,5,6, where an instruction cue is used to direct only attention to a peripheral stimulus location but then the eye movement is made to the mirror opposite position. Yet again we measure behavior by recording the eye movements of participants which allows for the sorting of the behavioral responses into correct and error trials7 which then can be correlated to brain activity. Neuroimaging now allows researchers to measure different behaviors of correct and error trials that are indicative of different cognitive processes and pinpoint the different neural networks involved.

The goal of our research is to correlate behavior to brain activity. Accurate behavioral measures and imaging techniques allow us to elucidate brain-behavior relationships.

Correlacionando as respostas comportamentais aos sinais de fMRI córtex pré-frontal humano: Examinando Processos Cognitivos Usando Análise de Tarefa

The aim of this methods paper is to describe how to implement a neuroimaging technique to examine complementary brain processes engaged by two similar ...

An Injury Paradigm to Investigate Central Nervous System Repair in Drosophila

An experimental method has been developed to investigate the cellular responses to central nervous system (CNS) injury using the fruit-fly Drosophila. Understanding repair and regeneration in animals is a key question in biology. The damaged human CNS does not regenerate, and understanding how to promote the regeneration is one of main goals of medical neuroscience. The powerful genetic toolkit of Drosophila can be used to tackle the problem of CNS regeneration.
A lesion to the CNS ventral nerve cord (VNC, equivalent to the vertebrate spinal cord) is applied manually with a tungsten needle. The VNC can subsequently be filmed in time-lapse using laser scanning confocal microscopy for up to 24 hr to follow the development of the lesion over time. Alternatively, it can be cultured, then fixed and stained using immunofluorescence to visualize neuron and glial cells with confocal microscopy. Using appropriate markers, changes in cell morphology and cell state as a result of injury can be visualized. With ImageJ and purposely developed plug-ins, quantitative and statistical analyses can be carried out to measure changes in wound size over time and the effects of injury in cell proliferation and cell death. These methods allow the analysis of large sample sizes. They can be combined with the powerful genetics of Drosophila to investigate the molecular mechanisms underlying CNS regeneration and repair.

An Injury Paradigm to Investigate Central Nervous System Repair in Drosophila

An injury paradigm using the Drosophila larval ventral nerve cord to investigate central nervous system regeneration and repair is described. Stabbing followed by laser scanning confocal microscopy in time-lapse and fixed specimens, combined with quantitative analysis with purposefully developed software and genetics, are used to investigate the molecular mechanisms of CNS regeneration and repair.

Um Paradigma para Investigar Lesão de reparação do sistema nervoso central em<em&gt; Drosophila</em

An experimental method has been developed to investigate the cellular responses to central nervous system (CNS) injury using the fruit-fly Drosophila. ...

Electrophysiological Method for Recording Intracellular Voltage Responses of Drosophila Photoreceptors and Interneurons to Light Stimuli In Vivo

Voltage responses of insect photoreceptors and visual interneurons can be accurately recorded with conventional sharp microelectrodes. The method described here enables the investigator to measure long-lasting (from minutes to hours) high-quality intracellular responses from single Drosophila R1-R6 photoreceptors and Large Monopolar Cells (LMCs) to light stimuli. Because the recording system has low noise, it can be used to study variability among individual cells in the fly eye, and how their outputs reflect the physical properties of the visual environment. We outline all key steps in performing this technique. The basic steps in constructing an appropriate electrophysiology set-up for recording, such as design and selection of the experimental equipment are described. We also explain how to prepare for recording by making appropriate (sharp) recording and (blunt) reference electrodes. Details are given on how to fix an intact fly in a bespoke fly-holder, prepare a small window in its eye and insert a recording electrode through this hole with minimal damage. We explain how to localize the center of a cell's receptive field, dark- or light-adapt the studied cell, and to record its voltage responses to dynamic light stimuli. Finally, we describe the criteria for stable normal recordings, show characteristic high-quality voltage responses of individual cells to different light stimuli, and briefly define how to quantify their signaling performance. Many aspects of the method are technically challenging and require practice and patience to master. But once learned and optimized for the investigator's experimental objectives, it grants outstanding in vivo neurophysiological data.

Electrophysiological Method for Recording Intracellular Voltage Responses of Drosophila Photoreceptors and Interneurons to Light Stimuli In Vivo

Sharp microelectrodes enable accurate electrophysiological characterization of photoreceptor and visual interneuron output in living Drosophila. Here we show how to use this method to record high-quality voltage responses of individual cells to controlled light stimulation. This method is ideal for studying neural information processing in insect compound eyes.

Método eletrofisiológico para respostas gravação intracelular de tensão<em&gt; Drosophila</em&gt; Fotorreceptores e Interneurônios à luz Estímulos<em&gt; In Vivo</em

Voltage responses of insect photoreceptors and visual interneurons can be accurately recorded with conventional sharp microelectrodes. The method ...

A Computerized Test Battery to Study Pharmacodynamic Effects on the Central Nervous System of Cholinergic Drugs in Early Phase Drug Development

Investigating potential pharmacodynamic effects in an early phase of central nervous system (CNS) drug research can provide valuable information for further development of new compounds. A computerized and thoroughly validated battery of neuropsychological and neurophysiological tests has been shown to be sensitive to detect drug-induced effects of multiple new and existing compounds. The test battery covers the main CNS domains, which have been shown to respond to drug effects and can be repeatedly administered following drug administration to characterize the concentration-effect profile of a drug.
The standard tests in the battery are saccadic eye movement, smooth pursuit eye movement, the Bowdle visual analog scale (VAS), the Bond and Lader VAS, body sway, adaptive tracking, visual verbal learning, and quantitative electroencephalography (qEEG). However, the test battery is adaptive in nature, meaning that it can be composed and adjusted with tests fit to investigate specific drug classes, or even specific receptors.
Showing effects of new cholinergic drugs designed to have a pro-cognitive outcome has been difficult. The pharmacological challenge model is a tool for early proof-of-pharmacology. Here, a marketed drug is used to induce temporary and reversible disease-like symptoms in healthy subjects, via a pharmacological mechanism related to the disease that is targeted as indication for the new compound. The test battery was implemented to investigate the potential of the nicotinic receptor antagonist mecamylamine to be used as a challenge model for cholinergic dysfunction, as seen in neurodegenerative disorders.
A worsening of scores in a dose dependent manner on the visual verbal learning test (VVLT; a test for learning and memory abilities) and the adaptive tracking test (a measure of visuomotor control and arousal), in particular, showed that the test battery is sensitive to showing acute pharmacodynamic effect after administration of anti-cholinergic drugs.

A validated computerized battery of neuropsychological and neurophysiological tests is used to study pharmacodynamic effects on the central nervous system of newly developed drugs in early phase development. To demonstrate the test battery, the acute effects of mecamylamine and the reversal of these effects by two agonist drugs are described.

Uma bateria de testes informatizados para estudar os efeitos farmacodinâmicos no sistema nervoso Central de drogas colinérgicas em fase inicial de desenvolvimento de drogas

Investigating potential pharmacodynamic effects in an early phase of central nervous system (CNS) drug research can provide valuable information for ...

An In Ovo Model for Testing Insulin-mimetic Compounds

Elevated blood glucose levels in type 2 diabetes mellitus (T2DM), a complex and multifactorial metabolic disease, are caused by insulin resistance and &#946;-cell failure. Various strategies, including the injection of insulin or the usage of insulin-sensitizing drugs, were pursued to treat T2DM or at least reduce the symptoms. In addition, the application of herbal compounds has attracted increasing attention. Thus, it is necessary to find efficient test systems to identify and characterize insulin-mimetic compounds. Here we developed a modified chick embryo model, which enables testing of synthetic compounds and herbal extracts with insulin-mimetic properties. Using a fluorescence microscopy-based primary screen, which quantifies the translocation of Glucose transporter 4 (Glut4) to the plasma membrane, we were able to identify compounds, mainly herbal extracts, which lead to an increase of intracellular glucose concentrations in adipocytes. However, the efficacy of these substances requires further verification in a living organism. Thus, we used an in-ovo approach to identify their blood glucose-reducing properties. The approval by an ethics committee is not needed since the use of chicken embryos during the first two-thirds of embryonic development is not considered an animal experiment. Here, the application of this model is described in detail.

An In Ovo Model for Testing Insulin-mimetic Compounds

In this study, we describe an in-ovo system as a promising tool to test insulin-mimetic compounds in a living organism. The main advantages include adequate throughput rates and acceptable costs, which enable the identification of phytochemicals with insulin-mimetic properties.

Um modelo em Ovo para testar compostos insulino-mimética

Elevated blood glucose levels in type 2 diabetes mellitus (T2DM), a complex and multifactorial metabolic disease, are caused by insulin resistance and ...

FM Dye Cycling at the Synapse: Comparing High Potassium Depolarization, Electrical and Channelrhodopsin Stimulation

FM dyes are used to study the synaptic vesicle (SV) cycle. These amphipathic probes have a hydrophilic head and hydrophobic tail, making them water-soluble with the ability to reversibly enter and exit membrane lipid bilayers. These styryl dyes are relatively non-fluorescent in aqueous medium, but insertion into the outer leaflet of the plasma membrane causes a &#62;40X increase in fluorescence. In neuronal synapses, FM dyes are internalized during SV endocytosis, trafficked both within and between SV pools, and released with SV exocytosis, providing a powerful tool to visualize presynaptic stages of neurotransmission. A primary genetic model of glutamatergic synapse development and function is the Drosophila neuromuscular junction (NMJ), where FM dye imaging has been used extensively to quantify SV dynamics in a wide range of mutant conditions. The NMJ synaptic terminal is easily accessible, with a beautiful array of large synaptic boutons ideal for imaging applications. Here, we compare and contrast the three ways to stimulate the Drosophila NMJ to drive activity-dependent FM1-43 dye uptake/release: 1) bath application of high [K+] to depolarize neuromuscular tissues, 2) suction electrode motor nerve stimulation to depolarize the presynaptic nerve terminal, and 3) targeted transgenic expression of channelrhodopsin variants for light-stimulated, spatial control of depolarization. Each of these methods has benefits and disadvantages for the study of genetic mutation effects on the SV cycle at the Drosophila NMJ. We will discuss these advantages and disadvantages to assist the selection of the stimulation approach, together with the methodologies specific to each strategy. In addition to fluorescent imaging, FM dyes can be photoconverted to electron-dense signals visualized using transmission electron microscopy (TEM) to study SV cycle mechanisms at an ultrastructural level. We provide the comparisons of confocal and electron microscopy imaging from the different methods of Drosophila NMJ stimulation, to help guide the selection of future experimental paradigms.

Synaptic vesicle (SV) cycling is the core mechanism of intercellular communication at neuronal synapses. FM dye uptake and release are the primary means of quantitatively assaying SV endo- and exocytosis. Here, we compare all the stimulation methods to drive FM1-43 cycling at the Drosophila neuromuscular junction (NMJ) model synapse.

Tintura de FM ciclismo a sinapse: comparando a despolarização de potássio alto, elétrica e Channelrhodopsin estimulação

FM dyes are used to study the synaptic vesicle (SV) cycle. These amphipathic probes have a hydrophilic head and hydrophobic tail, making them ...

The Combined Use of Transcranial Direct Current Stimulation and Robotic Therapy for the Upper Limb

Neurologic disorders such as stroke and cerebral palsy are leading causes of long-term disability and can lead to severe incapacity and restriction of daily activities due to lower and upper limb impairments. Intensive physical and occupational therapy are still considered main treatments, but new adjunct therapies to standard rehabilitation that may optimize functional outcomes are being studied.
Transcranial direct current stimulation (tDCS) is a noninvasive brain stimulation technique that polarizes underlying brain regions through the application of weak direct currents through electrodes on the scalp, modulating cortical excitability. Increased interest in this technique can be attributed to its low cost, ease of use, and effects on human neural plasticity. Recent research has been performed to determine the clinical potential of tDCS in diverse conditions such as depression, Parkinson&#39;s disease, and motor rehabilitation after stroke. tDCS helps enhance brain plasticity and seems to be a promising technique in rehabilitation programs.
A number of robotic devices have been developed to assist in the rehabilitation of upper limb function after stroke. The rehabilitation of motor deficits is often a long process requiring multidisciplinary approaches for a patient to achieve maximum independence. These devices do not intend to replace manual rehabilitation therapy; instead, they were designed as an additional tool to rehabilitation programs, allowing immediate perception of results and tracking of improvements, thus helping patients to stay motivated.
Both tDSC and robot-assisted therapy are promising add-ons to stroke rehabilitation and target the modulation of brain plasticity, with several reports describing their use to be associated with conventional therapy and the improvement of therapeutic outcomes. However, more recently, some small clinical trials have been developed that describe the associated use of tDCS and robot-assisted therapy in stroke rehabilitation. In this article, we describe the combined methods used in our institute for improving motor performance after stroke.

The combined use of transcranial direct current stimulation and robotic therapy as an add-on for conventional rehabilitation therapy may result in improved therapeutic outcomes due to modulation of brain plasticity. In this article, we describe the combined methods used in our institute for improving motor performance after stroke.

O uso combinado de terapia robótica e atual estimulação transcraniana direto para o membro superior

Neurologic disorders such as stroke and cerebral palsy are leading causes of long-term disability and can lead to severe incapacity and restriction of ...

The Evoked Potential Operant Conditioning System (EPOCS): A Research Tool and an Emerging Therapy for Chronic Neuromuscular Disorders

The Evoked Potential Operant Conditioning System (EPOCS) is a software tool that implements protocols for operantly conditioning stimulus-triggered muscle responses in people with neuromuscular disorders, which in turn can improve sensorimotor function when applied appropriately. EPOCS monitors the state of specific target muscles&#8212;e.g., from surface electromyography (EMG) while standing, or from gait cycle measurements while walking on a treadmill&#8212;and automatically triggers calibrated stimulation when pre-defined conditions are met. It provides two forms of feedback that enable a person to learn to modulate the targeted pathway&#39;s excitability. First, it continuously monitors ongoing EMG activity in the target muscle, guiding the person to produce a consistent level of activity suitable for conditioning. Second, it provides immediate feedback of the response size following each stimulation and indicates whether it has reached the target value.
To illustrate its use, this article describes a protocol through which a person can learn to decrease the size of the Hoffmann reflex&#8212;the electrically-elicited analog of the spinal stretch reflex&#8212;in the soleus muscle. Down-conditioning this pathway&#39;s excitability can improve walking in people with spastic gait due to incomplete spinal cord injury. The article demonstrates how to set up the equipment; how to place stimulating and recording electrodes; and how to use the free software to optimize electrode placement, measure the recruitment curve of direct motor and reflex responses, measure the response without operant conditioning, condition the reflex, and analyze the resulting data. It illustrates how the reflex changes over multiple sessions and how walking improves. It also discusses how the system can be applied to other kinds of evoked responses and to other kinds of stimulation, e.g., motor evoked potentials to transcranial magnetic stimulation; how it can address various clinical problems; and how it can support research studies of sensorimotor function in health and disease.

The Evoked Potential Operant Conditioning System EPOCS: A Research Tool and an Emerging Therapy for Chronic Neuromuscular Disorders

The Evoked Potential Operant Conditioning System aids scientific investigation of sensorimotor function and can administer targeted neurobehavioral training that can impact sensorimotor rehabilitation in neuromuscular disorders. This article describes its capabilities and illustrates its application in modifying a simple spinal reflex to achieve lasting improvement in motor function.

O Sistema de Condicionamento Operante de Potencial Evocado (EPOCS): Uma Ferramenta de Pesquisa e uma Terapia Emergente para Distúrbios Neuromusculares Crônicos

The Evoked Potential Operant Conditioning System (EPOCS) is a software tool that implements protocols for operantly conditioning stimulus-triggered muscle ...