This study was supported in part by an Israel Science Foundation (ISF) grant (297/18). The authors thank M. Bronfeld for establishing the acute rodent model and M. Israelashvili for her comments.

<ol>
	<li>American Psychiatric Association. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=DSM-5.">DSM-5.</a> American Psychiatric Association. , (2013).</li><li>Peterson, B. S., Leckman, J. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+temporal+dynamics+of+tics+in+Gilles+de+la+Tourette+syndrome.">The temporal dynamics of tics in Gilles de la Tourette syndrome.</a> Biol.Psychiatry. 44, 1337-1348 (1998).</li><li>Ganos, 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=The+somatotopy+of+tic+inhibition:+where+and+how+much.">The somatotopy of tic inhibition: where and how much.</a> Movement Disorders. , (2015).</li><li>Barnea, M., 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=Subjective+versus+objective+measures+of+tic+severity+in+Tourette+syndrome+-+The+influence+of+environment.">Subjective versus objective measures of tic severity in Tourette syndrome - The influence of environment.</a> Psychiatry Research. 242, 204-209 (2016).</li><li>Silva, R. R., Munoz, D. M., Barickman, J., Friedhoff, A. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Environmental+Factors+and+Related+Fluctuation+of+Symptoms+in+Children+and+Adolescents+with+Tourette's+Disorder.">Environmental Factors and Related Fluctuation of Symptoms in Children and Adolescents with Tourette's Disorder.</a> Journal of Child Psychology and Psychiatry. 36 (2), 305-312 (1995).</li><li>Rothenberger, A., 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=Sleep+and+Tourette+syndrome.">Sleep and Tourette syndrome.</a> Advances in Neurology. 85, 245-259 (2001).</li><li>Conelea, C. a., Woods, D. W., Brandt, B. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+impact+of+a+stress+induction+task+on+tic+frequencies+in+youth+with+Tourette+Syndrome.">The impact of a stress induction task on tic frequencies in youth with Tourette Syndrome.</a> Behaviour Research and Therapy. 49 (8), 492-497 (2011).</li><li>Ganos, C., Rothwell, J., Haggard, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Voluntary+inhibitory+motor+control+over+involuntary+tic+movements.">Voluntary inhibitory motor control over involuntary tic movements.</a> Movement Disorders. 33 (6), 937-946 (2018).</li><li>Yael, D., Vinner, E., Bar-Gad, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pathophysiology+of+tic+disorders.">Pathophysiology of tic disorders.</a> Movement Disorders. 30 (9), 1171-1178 (2015).</li><li>Kurvits, L., Martino, D., Ganos, C., Eddy, C. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Clinical+Features+That+Evoke+the+Concept+of+Disinhibition+in+Tourette+Syndrome.">Clinical Features That Evoke the Concept of Disinhibition in Tourette Syndrome.</a> Frontiers in Psychiatry. 11, 1-10 (2020).</li><li>Mink, J. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Basal+ganglia+dysfunction+in+Tourette's+syndrome:+a+new+hypothesis.">Basal ganglia dysfunction in Tourette's syndrome: a new hypothesis.</a> Pediatric Neurology. 25, 190-198 (2001).</li><li>Bronfeld, M., Bar-Gad, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tic+disorders:+what+happens+in+the+basal+ganglia.">Tic disorders: what happens in the basal ganglia.</a> The Neuroscientist. 19 (1), 101-108 (2013).</li><li>Tarsy, D., Pycock, C. J., Meldrum, B. S., Marsden, C. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Focal+contralateral+myoclonus+produced+by+inhibition+of+GABA+action+in+the+caudate+nucleus+of+rats.">Focal contralateral myoclonus produced by inhibition of GABA action in the caudate nucleus of rats.</a> Brain. 101 (1), 143-162 (1978).</li><li>Crossman, A. R., Mitchell, I. J., Sambrook, M. A., Jackson, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chorea+and+Myoclonus+in+the+Monkey+Induced+By+Gamma-Aminobutyric+Acid+Antagonism+in+the+Lentiform+Complex.">Chorea and Myoclonus in the Monkey Induced By Gamma-Aminobutyric Acid Antagonism in the Lentiform Complex.</a> Brain. 111 (5), 1211-1233 (1988).</li><li>McCairn, K. W., Bronfeld, M., Belelovsky, K., Bar-Gad, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+neurophysiological+correlates+of+motor+tics+following+focal+striatal+disinhibition.">The neurophysiological correlates of motor tics following focal striatal disinhibition.</a> Brain. 132 (8), 2125-2138 (2009).</li><li>Worbe, Y., 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=Behavioral+and+movement+disorders+induced+by+local+inhibitory+dysfunction+in+primate+striatum.">Behavioral and movement disorders induced by local inhibitory dysfunction in primate striatum.</a> Cerebral Cortex. 19 (8), 1844-1856 (2009).</li><li>Pogorelov, V., Xu, M., Smith, H. R., Buchanan, G. F., Pittenger, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Corticostriatal+interactions+in+the+generation+of+tic-like+behaviors+after+local+striatal+disinhibition.">Corticostriatal interactions in the generation of tic-like behaviors after local striatal disinhibition.</a> Experimental Neurology. 265, 122-128 (2015).</li><li>Bronfeld, M., Yael, D., Belelovsky, K., Bar-Gad, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Motor+tics+evoked+by+striatal+disinhibition+in+the+rat.">Motor tics evoked by striatal disinhibition in the rat.</a> Frontiers in Systems Neuroscience. 7, 50 (2013).</li><li>Vinner, E., Israelashvili, M., Bar-Gad, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Prolonged+striatal+disinhibition+as+a+chronic+animal+model+of+tic+disorders.">Prolonged striatal disinhibition as a chronic animal model of tic disorders.</a> Journal of Neuroscience Methods. 292, 20-29 (2017).</li><li>Paxinos, G., Watson, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> The Rat Brain in Stereotaxic Coordinates. 6, (2007).</li><li>Flecknell, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Analgesia+and+Post-Operative+Care.">Analgesia and Post-Operative Care.</a> Laboratory Animal Anaesthesia. , (2016).</li><li>Israelashvili, M., Bar-Gad, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Corticostriatal+divergent+function+in+determining+the+temporal+and+spatial+properties+of+motor+tics.">Corticostriatal divergent function in determining the temporal and spatial properties of motor tics.</a> Journal of Neuroscience. 35 (50), 16340-16351 (2015).</li><li>Bronfeld, M., Belelovsky, K., Bar-Gad, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Spatial+and+temporal+properties+of+tic-related+neuronal+activity+in+the+cortico-basal+ganglia+loop.">Spatial and temporal properties of tic-related neuronal activity in the cortico-basal ganglia loop.</a> Journal of Neuroscience. 31 (24), 8713-8721 (2011).</li><li>McCairn, K. W., 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=A+Primary+Role+for+Nucleus+Accumbens+and+Related+Limbic+Network+in+Vocal+Tics.">A Primary Role for Nucleus Accumbens and Related Limbic Network in Vocal Tics.</a> Neuron. 89 (2), 300-307 (2016).</li><li>Rizzo, F., 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=Aripiprazole+Selectively+Reduces+Motor+Tics+in+a+Young+Animal+Model+for+Tourette's+Syndrome+and+Comorbid+Attention+Deficit+and+Hyperactivity+Disorder.">Aripiprazole Selectively Reduces Motor Tics in a Young Animal Model for Tourette's Syndrome and Comorbid Attention Deficit and Hyperactivity Disorder.</a> Frontiers in Neurology. 9, 1-11 (2018).</li><li>Vinner, E., Matzner, A., Belelovsky, K., Bar-gad, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dissociation+of+tic+expression+from+its+neuronal+encoding+in+the+striatum+during+sleep.">Dissociation of tic expression from its neuronal encoding in the striatum during sleep.</a> bioRxiv. , (2020).</li><li>Webster, K. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cortico-striate+interrelations+in+the+albino+rat.">Cortico-striate interrelations in the albino rat.</a> Journal of Anatomy. 95, 532-544 (1961).</li><li>Ebrahimi, A., Pochet, R., Roger, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Topographical+organization+of+the+projections+from+physiologically+identified+areas+of+the+motor+cortex+to+the+striatum+in+the+rat.">Topographical organization of the projections from physiologically identified areas of the motor cortex to the striatum in the rat.</a> Neuroscience Research. 14, 39-60 (1992).</li><li>Brown, L. L., Sharp, F. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Metabolic+mapping+of+rat+striatum:+somatotopic+organization+of+sensorimotor+activity.">Metabolic mapping of rat striatum: somatotopic organization of sensorimotor activity.</a> Brain Research. 686, 207-222 (1995).</li><li>Brown, L. L., Smith, D. M., Goldbloom, L. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Organizing+principles+of+cortical+integration+in+the+rat+neostriatum:+Corticostriate+map+of+the+body+surface+is+an+ordered+lattice+of+curved+laminae+and+radial+points.">Organizing principles of cortical integration in the rat neostriatum: Corticostriate map of the body surface is an ordered lattice of curved laminae and radial points.</a> Journal of Comparative Neurology. 392 (4), 468-488 (1998).</li><li>Yael, D., Tahary, O., Gurovich, B., Belelovsky, K., Bar-Gad, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Disinhibition+of+the+nucleus+accumbens+leads+to+macro-scale+hyperactivity+consisting+of+micro-scale+behavioral+segments+encoded+by+striatal+activity.">Disinhibition of the nucleus accumbens leads to macro-scale hyperactivity consisting of micro-scale behavioral segments encoded by striatal activity.</a> The Journal of Neuroscience. , 3120 (2019).</li><li>Obeso, J. A., Rothwell, J. C., Marsden, C. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+spectrum+of+cortical+myoclonus.+From+focal+reflex+jerks+to+spontaneous+motor+epilepsy.">The spectrum of cortical myoclonus. From focal reflex jerks to spontaneous motor epilepsy.</a> Brain. 108, 124-193 (1985).</li><li>Bronfeld, M., 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=Bicuculline-induced+chorea+manifests+in+focal+rather+than+globalized+abnormalities+in+the+activation+of+the+external+and+internal+globus+pallidus.">Bicuculline-induced chorea manifests in focal rather than globalized abnormalities in the activation of the external and internal globus pallidus.</a> Journal of Neurophysiology. 104 (6), 3261-3275 (2010).</li></ol>

The authors have nothing to disclose.

In this manuscript, we detailed the protocols of the acute and chronic models for tic induction in a freely behaving rat. These protocols describe the preparation of all components, the surgery and the experimental process which can be adapted for customization to meet specific research needs. The primary principle underlying these models is the direct local application of bicuculline to the motor areas of the striatum, which is known to play a key role in the pathophysiology of tic disorders10<su...

Tics are the defining symptom of Tourette syndrome (TS) and other tic disorders. Tics are described as sudden, rapid, recurrent movements (motor tics), or vocalizations (vocal tics)1. Tic expression typically fluctuates in its temporal (frequency)2 and spatial (intensity, body location)3 properties over multiple time scales (hours, days, months, and years). These changes are affected by different factors, such as environmental features4,5, behavioral states6,7, and voluntary and temporary suppression8.
Although the neuronal mechanism governing motor tics is still not fully understood, an increasing number of theoretical and experimental studies have provided new evidence as to its nature9. Currently, the pathophysiology of tic generation is thought to involve the cortico-basal ganglia (CBG) loop, and specifically is associated with abnormal inhibition of the striatum, the primary basal ganglia input nucleus10,11,12. Previous studies in rodents and primates have demonstrated that the striatum can be disinhibited by local application of different GABAA antagonists, such as bicuculline and picrotoxin13,14,15,16,17,18. This pharmacological intervention leads to transient motor tic expression in the contralateral side to the injection, thus establishing a robust acute model of tic disorders with face and construct validity. The acute model is simple to induce and makes it possible to study the effects of short-term modulation such as electrical and optical stimulation concurrent with electrophysiological and kinematic recordings before, during and after tic expression. However, the acute model is limited to the short time period following the injection. Based on the acute model, we recently proposed a chronic model of tic generation in rats that utilizes a prolonged, fixed-rate infusion of bicuculline to the striatum via a subcutaneous-implanted mini-osmotic pump19. This model extends the period of tic expression to multiple days/weeks. The constant release of bicuculline over a lengthy period of time allows for the examination of the effects of a variety of factors such as pharmacological treatments and behavioral states on tic expression.
Here, we present protocols for generating the acute and chronic models of tic expression in rats. As a function of the specific research question, the protocols enable the fine-tuning of the parameters including unilateral versus bilateral implantation, the site of the tics (according to the somatotopic organization of the striatum)18 and the angle of the implant-cannula (depending on the location of additional implanted devices). The method used in the chronic model is partially based on commercial products but with critical adjustments to fit the tic model. This article details the adjustments needed to custom tailor these tic models.

<table><tbody><tr><td>Anchor screws</td><td>Micro Fasteners</td><td>SMPPS0002</td><td>#0 x 1/8 - Pan Head Sheet Metal Screws</td></tr><tr><td>Bicuculline methiodide</td><td>Sigma Aldrich</td><td>14343</td><td></td></tr><tr><td>Cyanoacrylate (CA) accelerator</td><td>Zap</td><td>PT29</td><td></td></tr><tr><td>Cyanoacrylate (CA) glue</td><td>BSI</td><td>IC-2000</td><td>This glue was found to be stronger than others</td></tr><tr><td>Dental cement</td><td>Coltene</td><td>H00322</td><td>Hygenic Perm Repair Material Reline Resin Self Cure</td></tr><tr><td>Glue gel</td><td>Loctite</td><td></td><td>Ultra Gel Control</td></tr><tr><td>Hemostat</td><td>WPI</td><td>501242</td><td>Any hemostat sized approximately 14 cm would be sufficient</td></tr><tr><td>Hypo-tube, extra-thin wall 25G</td><td>Component supply company</td><td>HTX-25X</td><td></td></tr><tr><td>Hypo-tube, regular wall 22G</td><td>Component supply company</td><td>HTX-22R</td><td></td></tr><tr><td>Hypo-tube, regular wall 30G</td><td>Component supply company</td><td>HTX-30R</td><td></td></tr><tr><td>Infusion pump machine</td><td>New Era Pump Systems</td><td>NE-1000</td><td></td></tr><tr><td>Mini-osmotic pump</td><td>ALZET</td><td>2001</td><td>1.0&amp;micro;l per hour, 7 days</td></tr><tr><td>PE compatible adhesive</td><td>CEYS</td><td></td><td>Special difficult plastics (suitable for PE)</td></tr><tr><td>PE-10 Catheter Tubing</td><td>ALZET</td><td>PE-10</td><td>ID = 0.28mm, OD = 0.61mm</td></tr><tr><td>Precision glass microsyringe, 10&amp;micro;l</td><td>Hamilton</td><td>80065</td><td>1701 RNR 10&amp;micro;l syr (22s/51/3)</td></tr><tr><td>Tissue adhesive</td><td>3M</td><td>1469Sb</td><td>Vetbond</td></tr><tr><td>Tubing-adapter</td><td>CMA</td><td>3409500</td><td></td></tr><tr><td>Tygon micro bore tubing, 0.02 inch ID * 0.06 OD</td><td>Component supply company</td><td>TND80-020</td><td></td></tr><tr><td>Wire 0.005-inch</td><td>Component supply company</td><td>GWX-0050</td><td></td></tr><tr><td>Wire 0.013-inch</td><td>Component supply company</td><td>GWX-0130</td><td></td></tr></tbody></table>

generating acute and chronic experimental models of motor tic expression in rats

Motor tics are sudden, rapid, recurrent movements that are the key symptoms of Tourette syndrome and other tic disorders. The pathophysiology of tic generation is associated with abnormal inhibition of the basal ganglia, particularly its primary input structure, the striatum. In animal models of both rodents and non-human primates, local application of GABAA antagonists, such as bicuculline and picrotoxin, into the motor parts of the striatum induces local disinhibition resulting in the expression of motor tics.
Here, we present acute and chronic models of motor tics in rats. In the acute model, bicuculline microinjections through a cannula implanted in the dorsal striatum elicit the expression of tics lasting for short time periods of up to an hour. The chronic model is an alternative enabling the extension of tic expression to periods of several days or even weeks, utilizing continuous infusion of bicuculline via a sub-cutaneous mini-osmotic pump.
The models enable the study of the behavioral and neural mechanisms of tic generation throughout the cortico-basal ganglia pathway. The models support the implantation of additional recording and stimulation devices in addition to the injection cannulas, thus allowing for a wide variety of usages such as electrical and optical stimulation and electrophysiological recordings. Each method has different advantages and shortcomings: the acute model enables the comparison of the kinematic properties of movement and the corresponding electrophysiological changes before, during and after tic expression and the effects of short-term modulators on tic expression. This acute model is simple to establish; however, it is limited to a short period of time. The chronic model, while more complex, makes feasible the study of tic dynamics and behavioral effects on tic expression over prolonged periods. Thus, the type of empirical query drives the choice between these two complementary models of tic expression.

Protocols for generating the acute and chronic models for tic induction in rats were presented above. The protocols cover the full preparation for surgery and experiments (Figure 1 for the acute model, Figure 2 for the chronic model). The application of bicuculline into the motor areas of the striatum results in the expression of ongoing motor tics. Tics appear on the contralateral side to the application and are characterized by brief and repetitive muscle cont...

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Generating Acute and Chronic Experimental Models of Motor Tic Expression in Rats

We present protocols for generating acute and chronic experimental models of tic expression in freely behaving rats. The models are based on striatal cannula implantation and subsequent GABAA antagonist application. The acute model uses transient injections whereas the chronic model utilizes prolonged infusions via a subcutaneous implanted mini-osmotic pump.

Motor tics are sudden, rapid, recurrent movements that are the key symptoms of Tourette syndrome and other tic disorders. The pathophysiology of tic ...

generating-acute-chronic-experimental-models-motor-tic-expression

Research

JoVE Journal

Behavior

7.6K Views.  Bar-Ilan University. We present protocols for generating acute and chronic experimental models of tic expression in freely behaving rats. The models are based on striatal cannula implantation and subsequent GABAA antagonist application. The acute model uses transient injections whereas the chronic model utilizes prolonged infusions via a subcutaneous implanted mini-osmotic pump.

Video: Generating Acute and Chronic Experimental Models of Motor Tic Expression in Rats

Acquisition of a High-precision Skilled Forelimb Reaching Task in Rats

Movements are the main measurable output of central nervous system function. Developing behavioral paradigms that allow detailed analysis of motor learning and execution is of critical importance in order to understand the principles and processes that underlie motor function. Here we present a paradigm to study movement acquisition within a daily session of training (within-session) representing the fast learning component and primary acquisition as well as skilled motor learning over several training sessions (between-session) representing the slow learning component and consolidation of the learned task. This behavioral paradigm increases the degree of difficulty and complexity of the motor skill task due to two features: First, the animal realigns its body prior to each pellet retrieval forcing renewed orientation and preventing movement execution from the same angle. Second, pellets are grasped from a vertical post that matches the diameter of the pellet and is placed in front of the cage. This requires a precise grasp for successful pellet retrieval and thus prevents simple pulling of the pellet towards the animal. In combination with novel genetics, imaging and electrophysiological technologies, this behavioral method will aid to understand the morphological, anatomical and molecular underpinnings of motor learning and memory.

A paradigm is presented to analyze the acquisition of a high-precision skilled forelimb reaching task in rats.

Movements are the main measurable output of central nervous system function. Developing behavioral paradigms that allow detailed analysis of motor ...

Motor and Hippocampal Dependent Spatial Learning and Reference Memory Assessment in a Transgenic Rat Model of Alzheimer's Disease with Stroke

Alzheimer&#39;s disease (AD) is a debilitating neurodegenerative disease that results in neurodegeneration and memory loss. While age is a major risk factor for AD, stroke has also been implicated as a risk factor and an exacerbating factor. The co-morbidity of stroke and AD results in worsened stroke-related motor control and AD-related cognitive deficits when compared to each condition alone. To model the combined condition of stroke and AD, a novel transgenic rat model of AD, with a mutated form of amyloid precursor protein (a key protein involved in the development of AD) incorporated into its DNA, is given a small unilateral striatal stroke.
For a model with the combination of both stroke and AD, behavioral tests that assess stroke-related motor control, locomotion and AD-related cognitive function must be implemented. The cylinder task involves a cost-efficient, multipurpose apparatus that assesses spontaneous forelimb motor use. In this task, a rat is placed in a cylindrical apparatus, where the rat will spontaneously rear and contact the wall of the cylinder with its forelimbs. These contacts are considered forelimb motor use and quantified during video analysis after testing. Another cost-efficient motor task implemented is the beam-walk task, which assesses forelimb control, hindlimb control and locomotion. This task involves a rat walking across a wooden beam allowing for the assessment of limb motor control through analysis of forelimb slips, hindlimb slips and falls. Assessment of learning and memory is completed with Morris water maze for this behavioral paradigm. The protocol starts with spatial learning, whereby the rat locates a stationary hidden platform. After spatial learning, the platform is removed and both short-term and long-term spatial reference memory is assessed. All three of these tasks are sensitive to behavioral differences and completed within 28 days for this model, making this paradigm time-efficient and cost-efficient.

To investigate the co-morbid Alzheimer&#39;s disease (AD) and stroke condition in a novel model, three behavior tasks are described that assess both motor control and cognitive behaviors. These tasks include the beam-walk task, cylinder task and Morris water maze.

Alzheimer&#39;s disease (AD) is a debilitating neurodegenerative disease that results in neurodegeneration and memory loss. While age is a major risk ...

Medicine

Rodent Behavioral Testing to Assess Functional Deficits Caused by Microelectrode Implantation in the Rat Motor Cortex

Medical devices implanted in the brain hold tremendous potential. As part of a Brain Machine Interface (BMI) system, intracortical microelectrodes demonstrate the ability to record action potentials from individual or small groups of neurons. Such recorded signals have successfully been used to allow patients to interface with or control&#160;computers, robotic limbs, and their own limbs. However, previous animal studies have shown that a microelectrode implantation in the brain not only damages the surrounding tissue but can also result in functional deficits. Here, we discuss a series of behavioral tests to quantify potential motor impairments following the implantation of intracortical microelectrodes into the motor cortex of a rat. The methods for open field grid, ladder crossing, and grip strength testing provide valuable information regarding the potential complications resulting from a microelectrode implantation. The results of the behavioral testing are correlated with endpoint histology, providing additional information on the pathological outcomes and impacts of this procedure on the adjacent tissue.

We have shown that a microelectrode implantation in the motor cortex of rats causes immediate and lasting motor deficits. The methods proposed herein outline a microelectrode implantation surgery and three rodent behavioral tasks to elucidate potential changes in the fine or gross motor function due to implantation-caused damage to the motor cortex.

Medical devices implanted in the brain hold tremendous potential. As part of a Brain Machine Interface (BMI) system, intracortical microelectrodes ...

Bioengineering

Development of an Alpha-synuclein Based Rat Model for Parkinson's Disease via Stereotactic Injection of a Recombinant Adeno-associated Viral Vector

In order to study the molecular pathways of Parkinson&#39;s disease (PD) and to develop novel therapeutic strategies, scientific investigators rely on animal models. The identification of PD-associated genes has led to the development of genetic PD models. Most transgenic &#945;-SYN mouse models develop gradual &#945;-SYN pathology but fail to display clear dopaminergic cell loss and dopamine-dependent behavioral deficits. This hurdle was overcome by direct targeting of the substantia nigra with viral vectors overexpressing PD-associated genes. Local gene delivery using viral vectors provides an attractive way to express transgenes in the central nervous system. Specific brain regions can be targeted (e.g. the substantia nigra), expression can be induced in the adult setting and high expression levels can be achieved. Further, different vector systems based on various viruses can be used. The protocol outlines all crucial steps to perform a viral vector injection in the substantia nigra of the rat to develop a viral vector-based alpha-synuclein animal model for Parkinson&#39;s disease.

This manuscript describes how viral vector-mediated local gene delivery provides an attractive way to express transgenes in the central nervous system. The protocol outlines all crucial steps to perform a viral vector injection in the substantia nigra of the rat to develop a viral vector-based animal model for Parkinson's disease.

In order to study the molecular pathways of Parkinson&#39;s disease (PD) and to develop novel therapeutic strategies, scientific investigators rely on ...

Generation and On-Demand Initiation of Acute Ictal Activity in Rodent and Human Tissue

Controlling seizures remains a challenging issue for the medical community. To make progress, researchers need a way to extensively study seizure dynamics and investigate its underlying mechanisms. Acute seizure models are convenient, offer the ability to perform electrophysiological recordings, and can generate a large volume of electrographic seizure-like (ictal) events. The promising findings from acute seizure models can then be advanced to chronic epilepsy models and clinical trials. Thus, studying seizures in acute models that faithfully replicate the electrographic and dynamical signatures of a clinical seizure will be essential for making clinically relevant findings. Studying ictal events in acute seizure models prepared from human tissue is also important for making findings that are clinically relevant. The key focus in this paper is on the cortical 4-AP model due to its versatility in generating ictal events in both in vivo and in vitro studies, as well as in both mouse and human tissue. The methods in this paper will also describe an alternative method of seizure induction using the Zero-Mg2+ model and provide a detailed overview of the advantages and limitations of the epileptiform-like activity generated in the different acute seizure models. Moreover, by taking advantage of commercially available optogenetic mouse strains, a brief (30 ms) light pulse can be used to trigger an ictal event identical to those occurring spontaneously. Similarly, 30 - 100 ms puffs of neurotransmitters (Gamma-Amino Butyric Acid or glutamate) can be applied to the human tissue to trigger ictal events that are identical to those occurring spontaneously. The ability to trigger ictal events on-demand in acute seizure models offers the newfound ability to observe the exact sequence of events that underlie seizure initiation dynamics and efficiently evaluate potential anti-seizure therapies.

Acute seizure models are important for studying the mechanisms underlying epileptiform events. Furthermore, the ability to generate epileptiform events on-demand provides a highly efficient method to study the exact sequence of events underlying their initiation. Here, we describe the acute 4-aminopyridine cortical seizure models established in mouse and human tissue.

Controlling seizures remains a challenging issue for the medical community. To make progress, researchers need a way to extensively study seizure dynamics ...

Neuroscience

Establishment of Acute Pontine Infarction in Rats by Electrical Stimulation

Pontine infarction is the most common stroke subtype in the posterior circulation, while there lacks a rodent model mimicking pontine infarction. Provided here is a protocol for successfully establishing a rat model of acute pontine infarction. Rats weighing about 250 g are used, and a probe with an insulated sheath is injected into the pons using a stereotaxic apparatus. A lesion is produced by the electrical stimulation with a single pulse. The Longa score, Berderson score, and beam balance test are used to assess neurological deficits. Additionally, the adhesive-removal somatosensory test is used to determine sensorimotor function, and the limb placement test is used to evaluate proprioception. MRI scans are then used to assess the infarction in vivo, and TTC staining is used to confirm the infarction in vitro. Here, a successful infarction is identified that is located in the anterolateral basis of the rostral pons. In conclusion, a new method is described to establish an acute pontine infarction rat model.

Presented here is a protocol for establishing acute pontine infarction in a rat model via electrical stimulation with a single pulse.

Pontine infarction is the most common stroke subtype in the posterior circulation, while there lacks a rodent model mimicking pontine infarction. Provided ...

Preparation and Implantation of Electrodes for Electrically Kindling VGAT-Cre Mice to Generate a Model for Temporal Lobe Epilepsy

It was discovered that electrical kindling of VGAT-Cre mice led to the spontaneous motor and electrographic seizures. A recent paper focused on how unique VGAT-Cre mice were used in developing spontaneous recurring seizures (SRS) after kindling and a likely mechanism - insertion of Cre into the VGAT gene - disrupted its expression and reduced GABAergic tone. The present study extends these observations to a larger cohort of mice, focusing on key issues such as how long the SRS continues after kindling and the effect of the animal's sex and age. This report describes the protocols for the following key steps: making headsets with hippocampal depth electrodes for electrical stimulation and for reading the electroencephalogram; surgery to affix the headset securely on the mouse's skull so that it does not fall off; and key details of the electrical kindling protocol such as duration of the pulse, frequency of train, duration of train, and amount of current injected. The kindling protocol is robust in that it reliably leads to epilepsy in most VGAT-Cre mice, providing a new model to test for novel antiepileptogenic drugs.

This report describes the methods to generate a model of temporal lobe epilepsy based on the electrical kindling of transgenic VGAT-Cre mice. Kindled VGAT-Cre mice may be useful in determining what causes epilepsy and for screening novel therapies.

It was discovered that electrical kindling of VGAT-Cre mice led to the spontaneous motor and electrographic seizures. A recent paper focused on how unique ...

Generating the 6-hydroxydopamine Rat Model of Parkinson&#39;s Disease

Source: Guimar&#227;es, R. P., et al. <a href="https://app.jove.com/v/62923">The 6-hydroxydopamine Rat Model of Parkinson&#39;s Disease.</a> J. Vis. Exp. (2021).
This video demonstrates a procedure to create a rat model of Parkinson&#39;s disease by injecting the neurotoxin 6-hydroxydopamine (6-OHDA) into the brain. The neurotoxin infusion into the medial forebrain bundle (MFB) specifically targets dopaminergic neurons responsible for motor control, leading to their destruction and replicating Parkinson&#39;s disease symptoms.

All procedures involving animal models have been reviewed by the local institutional animal care committee and the JoVE veterinary review board.
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JoVE Encyclopedia of Experiments

Neuropathology

Neurodegenerative Diseases

Generating the Widespread Cerebral Cortical Demyelination in a Rat Model

Source: &#220;&#231;al, M. et al., <a href="https://app.jove.com/v/57879">Rat Model of Widespread Cerebral Cortical Demyelination Induced by an Intracerebral Injection of Pro-Inflammatory Cytokines.</a> J. Vis. Exp. (2021)
The video demonstrates a method for generating a rat model with widespread cerebral cortical demyelination. This involves disrupting the blood-brain barrier by injecting pro-inflammatory cytokines into mice primed with recombinant myelin sheath protein. This process facilitates the infiltration of immune cells, resulting in widespread cerebral cortical demyelination.

Immunology

Immunotherapy

Model Development and Disease Study

Inducing a Facial Nerve Injury in a Rat Model

After confirming a lack of response to toe pinch, apply ointment to the eyes of the rat, and shave the surgical area. Establish a method for rat identification, and place a roll of gauze under the neck.
Disinfect the exposed skin with three alternating chlorhexidine and 70% ethanol scrubs, and place the rat under a stereomicroscope. Manipulate the ipsilateral ear in an anterior-posterior direction to determine the natural folding of the postauricular skin. Use a number 15 blade to make a two to three-millimeter incision in the postauricular crease.
The planning and the placement of the incision are the most critical steps for ensuring reliable identification of the facial nerve while minimizing the wound size.
Bluntly dissect through the immediate subcutaneous fascia, and place a micro-Weitlaner retractor to enhance the tissue exposure. Identify the anterior digastric muscle as it travels in an inferior to superior direction towards its insertion along the skull base. Spread gently through the muscle belly along the muscle insertion point to reveal the tendon of the anterior digastric belly.
The tendon will appear as a filmy white process emanating from the muscle with a solid insertion onto the skull base. After identification of the anterior digastric muscle and its tendon, adjust the Weitlaner retractor to further retract the muscle belly.
The exposed region is the three-dimensional space in which the main trunk of the facial nerve lies. Dissect along the nerve in an inferior direction, distally from the exit of the stylomastoid foramen. For a simple transaction, grasp the immediate epineurium overlying the nerve with fine-toothed forceps, and use sharp micro-scissors to cleanly transect the nerve at the desired point with a single cut.
After the experimental injury has been delivered, irrigate the wound with sterile saline, and dry the tissue with sterile gauze, before closing the skin incision according to institutional guidelines.