Questo lavoro è supportato da un Discovery Grant al BDC del Natural Sciences and Engineering Research Council of Canada (NSERC; RGPIN 311680) e una sovvenzione operativa al BDC del Canadian Institutes of Health Research (CIHR; MOP-93796). RAK è stato supportato da una borsa di studio per laureati dell'Ontario e ALC è stato supportato da una sovvenzione NSERC CREATE. L'apparato sperimentale descritto in questo manoscritto è stato supportato dalla Canada Foundation for Innovation. Ulteriore sostegno è arrivato dal Canada First Research Excellence Fund (BrainsCAN).

<ol>
	<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. D. <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+upper+limb+muscles+and+corrective+reaches+are+preferentially+evoked+by+low+spatial+frequencies.">Stimulus-locked responses on human upper limb muscles and corrective reaches are preferentially evoked by low spatial frequencies.</a> eNeuro. 6 (5), (2019).</li><li>Kowler, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cognitive+expectations,+not+habits,+control+anticipatory+smooth+oculomotor+pursuit.">Cognitive expectations, not habits, control anticipatory smooth oculomotor pursuit.</a> Vision Research. 29 (9), 1049-1057 (1989).</li><li>Goonetilleke, S. 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. L., Everling, S., Ford, K., Mattar, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hand-eye+coordination+for+rapid+pointing+movements:+Arm+movement+direction+and+distance+are+specified+prior+to+saccade+onset.">Hand-eye coordination for rapid pointing movements: Arm movement direction and distance are specified prior to saccade onset.</a> Experimental Brain Research. 145 (3), 372-382 (2002).</li><li>Par&#233;, M., 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=Saccadic+reaction+time+in+the+monkey:+advanced+preparation+of+oculomotor+programs+is+primarily+responsible+for+express+saccade+occurrence.">Saccadic reaction time in the monkey: advanced preparation of oculomotor programs is primarily responsible for express saccade occurrence.</a> Journal of Neurophysiology. 76 (6), 3666-3681 (1996).</li></ol>

Gli autori non hanno nulla da rivelare.

Gli esseri umani hanno una notevole capacità, quando necessario, di generare azioni rapide e visivamente guidate a latenze che si avvicinano a ritardi di conduzione afferenti ed efferenti minimi. In precedenza abbiamo descritto le risposte bloccate da stimoli (SRS) sull'arto superiore come una nuova misura per le risposte rapide del visuomotor6,9,10. Sebbene utile nel fornire un benchmark trial-by-trial per il primo aspetto del...

Quando notiamo un messaggio sul nostro cellulare, ci viene richiesto di eseguire una copertura visivamente guidata per prendere il nostro telefono e leggere il messaggio. Caratteristiche visive come la forma e le dimensioni del telefono vengono trasformate in comandi motori che ci consentono di raggiungere con successo l'obiettivo. Tali trasformazioni visuomotor possono essere studiate in condizioni di laboratorio, che consentono un alto grado di controllo. Tuttavia, ci sono scenari in cui il tempo di risposta è importante, ad esempio, catturare il telefono se dovesse cadere. Gli studi di laboratorio sui comportamenti visuomotor veloci spesso si basano su paradigmi bersaglio spostati in cui i movimenti in corso vengono modificati a metà volo a seguito di alcuni cambiamenti nella posizione del bersaglio (ad esempio, vedi rif.1,2). Sebbene tali correzioni online possano verificarsi in <150 ms3, è difficile accertare la tempistica esatta dell'uscita rapida del visuomotor utilizzando la cinematica da sola a causa delle caratteristiche filtranti a passaggio basso del braccio e perché l'uscita rapida del visuomotor sostituisce un movimento già a metà volo. Tali complicazioni portano all'incertezza sui substrati alla base delle risposte rapide del visuomotor (vedi rif.4 per la revisione). Alcuni studi suggeriscono che strutture subcorticali come il collicolo superiore, piuttosto che aree corticali fronto-parietali, possono avviare correzioni online5.
Questa incertezza riguardo ai substrati neurali sottostanti può essere dovuta, almeno in parte, alla mancanza di un biomarcatore affidabile per l'uscita del sistema di visuomotor veloce. Recentemente, abbiamo descritto una misura di risposte visuomotor veloci che possono essere generate da posture statiche e registrate tramite elettromiografia (EMG). Le risposte bloccate da stimoli (SRS) sono raffiche di attività EMG bloccate nel tempo che precedono ilmovimento volontario 6,7, evolvendosi costantemente ~ 100 ms dopo l'inizio dello stimolo. Come suggerisce il nome, gli S SLR sono evocati dall'inizio dello stimolo, persistendo anche se un eventuale movimento vienetrattenuto 8 o si muove nella direzione opposta9. Inoltre, gli SLA evocati dallo spostamento del bersaglio in un paradigma dinamico sono associati a correzioni online di latenza piùbreve 10. Pertanto, gli SLA forniscono una misura oggettiva per studiare sistematicamente l'output di un sistema di visuomotor veloce coinvolto in TT a breve latenza, in quanto possono essere generati da una postura statica e analizzati da altri segnali EMG non correlati alla fase iniziale della risposta rapida del visuomotor.
L'obiettivo dello studio attuale è quello di presentare un paradigma di raggiungimento visivamente guidato che suscita robustamente gli SVOL. Studi precedenti che hanno studiato la SLR hanno riportato tassi di rilevamento inferiori al 100% tra i partecipanti, anche quando si utilizzano registrazioni intramuscolari più invasive6,8,9. Bassi tassi di rilevamento e il ricorso a registrazioni invasive limitano l'utilità delle misure SLR nelle future indagini sul sistema di visuomotor rapido nella malattia o per tutta la durata della vita. Mentre alcuni soggetti potrebbero semplicemente non esprimere SLR, gli stimoli e i paradigmi comportamentali usati in precedenza potrebbero non essere stati ideali per evocare la SLR. I rapporti passati degli SLA hanno in genere utilizzato paradigmi in cui i partecipanti generano raggiungementi guidati visivamente verso obiettivistatici,che appaiono improvvisamente 6,9. Tuttavia, un sistema di visuomotor veloce è il più probabile necessario in scenari in cui si deve interagire rapidamente con un oggetto che cade o vola, portando a chiedersi se lo spostamento piuttosto che gli stimoli statici possano evocare meglio gli S SLR. Pertanto, abbiamo adattato un paradigma target mobile utilizzato per studiare i movimentioculari 11e lo abbiamo combinato con un compito di raggiungimento guidato pro / anti visivamente utilizzato per esaminare l'SLR9. Rispetto ai risultati dei paradigmi utilizzati inprecedenza 6,8,9, è stato scoperto che gli SLA nel paradigma target emergente si sono evoluti prima, hanno raggiunto magnitudini più elevate e sono stati più diffusi nel campione dei partecipanti. Nel complesso, il paradigma target emergente promuove l'espressione di risposte visuomotor veloci a tal punto che le misure oggettive EMG possono essere fatte in modo affidabile con registrazioni superficiali, potenziando lo studio all'interno delle popolazioni cliniche e per tutta la durata della vita. Inoltre, il paradigma target emergente può essere modificato in molti modi diversi, promuovendo indagini più approfondite sui fattori sensoriali, cognitivi e motori che promuovono o modificano risposte visuomotor veloci.

<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

Le risposte bloccate allo stimolo (SRS) sono brevi raffiche di tempo di attività muscolare bloccate all'inizio dello stimolo che si evolvono ben prima della più grande raffica di reclutamento muscolare associata all'insorgenza del movimento. La natura time-locked della SLR ha prodotto una "fascia" di attività muscolare visibile a ~ 100 ms durante la visualizzazione di tutte le prove ordinate per il tempo di reazione (RT) (Figura 1a, evidenziata da scatole grigie). Come mostrato nella <str...

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

Presentato qui è un paradigma comportamentale che suscita solide risposte visuomotor veloci sui muscoli degli arti superiori umani durante i raggiungeli visivamente guidati.

Un paradigma bersaglio emergente per evocare risposte visuomotor veloci sui muscoli degli arti superiori umani

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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4.2K Views.  Western University. Presentato qui è un paradigma comportamentale che suscita solide risposte visuomotor veloci sui muscoli degli arti superiori umani durante i raggiungeli visivamente guidati.

Video: 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.

Registrazione di risposte comportamentali alla riflessione in gamberi di fiume

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

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Neuroscienze

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 di neuroni da fettine di cervello di roditore studio di trasmissione sinaptica e Immagine terminali presinaptici

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.

Correlare risposte comportamentali alla segnali fMRI di Human corteccia prefrontale: Esame Processi Cognitivi Utilizzando 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 ...

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.

Un paradigma Infortunio per Indagare riparazione del sistema nervoso centrale in<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.

Metodo elettrofisiologiche per la registrazione intracellulare di tensione Risposte di<em&gt; Drosophila</em&gt; Fotorecettori e Interneuroni a luce stimoli<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.

Una batteria di Test computerizzato per studiare effetti farmacodinamici sul sistema nervoso centrale di farmaci colinergici in fase precoce di sviluppo di farmaci

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.

Un modello In Ovo per testare composti insulino-mimetici

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 di FM in bicicletta alla sinapsi: confronto tra alto potassio depolarizzazione, elettrica e stimolazione Channelrhodopsin

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.

L'uso combinato di corrente stimolazione transcranica diretta e terapia robotica per l'arto superiore

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.

Il sistema di condizionamento operante potenziale evocato (EPOCS): uno strumento di ricerca e una terapia emergente per i disturbi neuromuscolari cronici

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