The study protocol was approved by the institutional clinical research ethics committee of Kyushu University, Fukuoka, Japan (IRB: Clinical Research number #28-77). Although the measurement of pupillary reaction is an essential and standard clinical procedure during anesthesia, informed consent was obtained for this research. Patients with cataract, glaucoma, intraocular lenses, or insulin-dependent diabetes mellitus were excluded because their pupillary responses may be abnormal.
1. Preparation for Electroconvulsive Therapy
<ol>
	<li>Clean the right and left forehead and area behind the ears with an alcohol cotton swab, and then attach electroencephalogram (EEG) monitors at four symmetrical points.</li>
	<li>Clean bilateral temples with normal saline, and then attach adhesive electrical stimulation pads (about 4 cm x 5 cm) to the bilateral temples to prevent interference in the stimulation due to hair. The intensity of stimulation is changed each time, according to the previous degree of inducted convulsion.</li>
	<li>Attach electrocardiogram (ECG) monitors at two points on the chest (base of the heart and cardiac apex) and monitor heart rate.</li>
	<li>Prepare a tourniquet and belt it at the left thigh. 
	NOTE: The tourniquet is belted until 200 mmHg after the patient is asleep. Convulsion induced by ECT can be observed in the lower leg even after systemic administration of muscular relaxant.</li>
	<li>Attach two electromyogram sensors to the left anterior tibial muscle, with a distance of 5 cm, to measure generalized seizure time in the lower leg.</li>
</ol>
2. Preparation for anesthesia
NOTE: All patients underwent ECT in the same room, at the same time of day.
<ol>
	<li>After the forehead is cleaned with an alcohol cotton swab, attach a bispectral index (BIS) measurement device to the patient&#8217;s forehead. BIS is used to monitor depth of anesthesia.</li>
	<li>Non-invasively measure blood pressure at the arm every 1 min during ECT therapy.</li>
	<li>Continuously monitor saturation of oxygen and pulse rate by a clip attached to the finger.</li>
	<li>Hold a pupillometer (see the Table of Materials) over one of the patient&#8217;s eyes. After the patient opens their eyes, press a button (Figure 1A) on the pupillometer, and measurement starts automatically. Maximum (initial) resting pupil size (MAX) and minimum pupil size after light stimulation (MIN) are automatically measured, and the constriction pupil size ratio (%constriction = [MAX&#8211;MIN]/MAX expressed as a percentage) is automatically calculated. 
	NOTE: The duration of light emission is 800 ms, and the required data can be obtained within 1 second. If the patient is unable to keep their eyes open, the examiner assists by holding the eyelid open. Although anesthetists typically measure the pupillary diameter or light reflex of patients before surgery in the operating room, cooperation with patients is needed before anesthesia induction.</li>
</ol>
3. Anesthesia
<ol>
	<li>Supply oxygen (6 L/min) via a mask.</li>
	<li>Administer propofol (sedative: 3 &#181;g/mL, target controlled infusion) via intravenous line until loss of consciousness.</li>
	<li>Tighten the tourniquet belted at the thigh to 200 mmHg.</li>
	<li>Administer succinylcholine (muscle relaxant: 1 mg/kg) via the intravenous line.</li>
	<li>After spontaneous breathing of patients ceases, have the anesthesiologist perform controlled ventilation using a face mask with 100% oxygen without intubation. Perform ventilation from the point at which end-tidal carbon dioxide is 30 mmHg until electrical stimulation10.</li>
	<li>After BIS value begins to increase, the anesthesiologist stops ventilation and psychiatrists start the ECT procedure.</li>
</ol>
4. Electroconvulsive Therapy Procedure
<ol>
	<li>Conduct ECT via bitemporal electrode stimulation using an ECT instrument. Set the initial electrical stimulus dose (%) at half the value of each individual&#8217;s age. 
	NOTE: Maximum stimulus dose is 100%. The electrical stimulation time is about 7-8 s.</li>
	<li>Immediately after electrical stimulation, hold thr automated infrared pupillometer over one of the patient&#8217;s eyes. At this time, if the patient closes their eyes, keep the patient&#8217;s eyelid open. Press the device button, as in step 2.4, and measure maximum (initial) resting pupil size (MAX) or minimum pupil size after stimulation (MIN).</li>
	<li>Perform controlled ventilation using a face mask with 100% oxygen until the patient begins breathing spontaneously.</li>
	<li>Using EEG, measure ictal regularity, seizure time and greater postictal suppression (by the psychiatrist [Figure 2, Figure 3]).</li>
</ol>

<ol>
	<li>Saito, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Anesthesia+management+for+electroconvulsive+therapy:+hemodynamic+and+respiratory+management.">Anesthesia management for electroconvulsive therapy: hemodynamic and respiratory management.</a> Journal of Anesthesia. 19 (2), 142-149 (2005).</li><li>Ward, H. B., Szabo, S. T., Rakesh, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Maintenance+ECT+in+schizophrenia:+A+systematic+review.">Maintenance ECT in schizophrenia: A systematic review.</a> Psychiatry Research. 264, 131-142 (2018).</li><li>Milev, R. 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=Canadian+Network+for+Mood+and+Anxiety+Treatments+(CANMAT)+2016+Clinical+Guidelines+for+the+Management+of+Adults+with+Major+Depressive+Disorder:+Section+4.+Neurostimulation+Treatments.">Canadian Network for Mood and Anxiety Treatments (CANMAT) 2016 Clinical Guidelines for the Management of Adults with Major Depressive Disorder: Section 4. Neurostimulation Treatments.</a> Canadian Journal of Psychiatry. 61 (9), 561-575 (2016).</li><li>Vutskits, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=General+Anesthetics+to+Treat+Major+Depressive+Disorder:+Clinical+Relevance+and+Underlying+Mechanisms.">General Anesthetics to Treat Major Depressive Disorder: Clinical Relevance and Underlying Mechanisms.</a> Anesthesia &amp; Analgesia. 126 (1), 208-216 (2018).</li><li>Nishikawa, K., Yamakage, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effects+of+the+concurrent+use+of+a+reduced+dose+of+propofol+with+divided+supplemental+remifentanil+and+moderate+hyperventilation+on+duration+and+morphology+of+electroconvulsive+therapy-induced+electroencephalographic+seizure+activity:+A+randomized+controlled+trial.">Effects of the concurrent use of a reduced dose of propofol with divided supplemental remifentanil and moderate hyperventilation on duration and morphology of electroconvulsive therapy-induced electroencephalographic seizure activity: A randomized controlled trial.</a> Journal of Clinical Anesthesia. 37, 63-68 (2017).</li><li>Ritter, A. 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=Brain+stem+blood+flow,+pupillary+response,+and+outcome+in+patients+with+severe+head+injuries.">Brain stem blood flow, pupillary response, and outcome in patients with severe head injuries.</a> Neurosurgery. 44 (5), 941-948 (1999).</li><li>Kobayashi, K., 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=Rapid+and+lasting+enhancement+of+dopaminergic+modulation+at+the+hippocampal+mossy+fiber+synapse+by+electroconvulsive+treatment.">Rapid and lasting enhancement of dopaminergic modulation at the hippocampal mossy fiber synapse by electroconvulsive treatment.</a> Journal of Neurophysiology. 117 (1), 284-289 (2017).</li><li>Meeker, 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=Pupil+examination:+validity+and+clinical+utility+of+an+automated+pupillometer.">Pupil examination: validity and clinical utility of an automated pupillometer.</a> Journal of Neuroscience Nursing. 37 (1), 34-40 (2005).</li><li>Shirozu, K., 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+relationship+between+seizure+in+electroconvulsive+therapy+and+pupillary+response+using+an+automated+pupilometer.">The relationship between seizure in electroconvulsive therapy and pupillary response using an automated pupilometer.</a> Journal of Anesthesia. , (2018).</li><li>Sawayama, E., 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=Moderate+hyperventilation+prolongs+electroencephalogram+seizure+duration+of+the+first+electroconvulsive+therapy.">Moderate hyperventilation prolongs electroencephalogram seizure duration of the first electroconvulsive therapy.</a> JOURNAL OF ECT. 24 (3), 195-198 (2008).</li><li>Rollins, M. D., Feiner, J. R., Lee, J. M., Shah, S., Larson, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pupillary+effects+of+high-dose+opioid+quantified+with+infrared+pupillometry.">Pupillary effects of high-dose opioid quantified with infrared pupillometry.</a> Anesthesiology. 121 (5), 1037-1044 (2014).</li><li>McNett, M., Moran, C., Janki, C., Gianakis, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Correlations+Between+Hourly+Pupillometer+Readings+and+Intracranial+Pressure+Values.">Correlations Between Hourly Pupillometer Readings and Intracranial Pressure Values.</a> Journal of Neuroscience Nursing. 49 (4), 229-234 (2017).</li><li>Shirozu, K., 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+effects+of+anesthetic+agents+on+pupillary+function+during+general+anesthesia+using+the+automated+infrared+quantitative+pupillometer.">The effects of anesthetic agents on pupillary function during general anesthesia using the automated infrared quantitative pupillometer.</a> Journal of Clinical Monitoring and Computing. 31 (2), 291-296 (2017).</li></ol>

The authors have nothing to disclose.

Automated infrared pupillometer devices have been used to measure pupillary reactions in clinical situation12. However, to our knowledge, no previous studies have used this equipment for detecting the efficacy of seizure induction by ECT. Resting pupil diameter size differs between patients, but constriction ratio provides an objective measure. Thus, we selected the constriction ratio change, not the diameter size change. Additionally, small changes of pupillary diameter can only be measured using...

Electroconvulsive therapy (ECT) is considered an effective treatment for severe neuropsychiatric disorders, including refractory psychosis, bipolar disorder, and depression1. In ECT, an electrical current is applied to the brain to induce a seizure under general anesthesia2. Although the mechanisms underlying ECT remain unclear, its antidepressant effects have been attributed to seizure-induced changes in neurotransmitter levels, improved neuroplasticity, increased functional connectivity, and an increase in the plasmatic production of brain-derived neurotrophic factor3. It has also been reported that ECT facilitates serotonin-, norepinephrine- and dopamine-mediated neurotransmission4. These findings suggest that ECT could cause activation of the sympathetic nervous system. Previous studies have evaluated adequate seizure induction by ECT using seizure duration, symmetrical seizure amplitude, postictal suppression, and activation of the sympathetic nervous system4,5. Among these factors, increased activation of the sympathetic nervous system cannot be measured using electroencephalography. Detection of sympathetic nervous system activation is dependent on increased blood pressure (BP) and heart rate (HR). However, these hemodynamic parameters do not always reflect sympathetic responses because of the administration of antihypertensive drugs to prevent cardiac events during ECT and anesthetic agents, which affect sympathetic nervous function.
Pupillary responses can reflect the degree of brain damage6. Thus, pupillary mydriasis is indicated for severe brain damage6. Artificial seizures induced by electrical stimulation constitute an abnormal state of brain activity. Thus, evaluating the pupillary response immediately after ECT may be useful for assessing the efficacy of ECT because ECT may also influence pupillary responses7. However, measuring pupillary responses in busy clinical situations, as in the current case, is often difficult. To address this issue, a measurement method using an infrared quantitative pupillometer could help to measure pupillary responses easily, accurately, objectively and reproducibly. Quantitative pupillary assessment methods are superior to those obtained manually at the bedside, even by experienced nurses and physicians8. The proposed method for measuring pupillary reactivity using an automated infrared pupillometer could be useful for detecting the degree of seizure or sympathetic nervous activation. In a previous study, we reported that the pupillary light reflex was related to the efficacy of seizure by ECT9. Specifically, we found that pupillary diameter was not changed after light stimulation, remaining enlarged when adequate seizure was induced. Thus, the aim of the proposed method is to measure the light reflex using an automated infrared pupillometer immediately after electrical stimulation. The proposed method is easy to perform, enabling any clinician, not only psychiatrists, to evaluate the efficacy of seizure induction using ECT.

<table><tbody><tr><td>Npi-100/automated infrared pupillometer&amp;nbsp;</td><td>NeurOptics</td><td></td><td></td></tr><tr><td>Thymatron IV system</td><td>Somatics Inc.</td><td></td><td></td></tr><tr><td>Thymapads&amp;trade;</td><td>Somatics Inc.</td><td>EPAD-C</td><td></td></tr><tr><td>BIS Quatro sensor</td><td>medtronic</td><td></td><td></td></tr><tr><td>Non invasive blood pressure cuff</td><td>Nihon Koden</td><td>YP-713T</td><td></td></tr><tr><td>VBM tourniquet9000</td><td>Medizintechnik GmbH</td><td></td><td></td></tr><tr><td>EEG</td><td>Somatics Inc.</td><td>ECEF-4</td><td></td></tr><tr><td>ECG</td><td>Somatics Inc.</td><td>ELDSC-9</td><td></td></tr><tr><td>EMG monitoring lead</td><td>Somatics Inc.</td><td>ELDS-BR</td><td></td></tr><tr><td>Finger probe</td><td>Nihon Koden</td><td>TL-201T</td><td></td></tr><tr><td>Npi-200/automated infrared pupillometer&amp;nbsp;</td><td>NeurOptics</td><td></td><td></td></tr></tbody></table>

pupillary response as assessment of effective seizure induction by electroconvulsive therapy

Electroconvulsive therapy (ECT) is reported to be effective for severe neuropsychiatric disorders. In ECT, electrical stimulation is applied to the brain, inducing seizure activity. Adequate seizure induction with ECT is associated with seizure duration, symmetrical high amplitude waveforms during slow-wave activity, postictal suppression, and activation of the sympathetic nervous system. Sympathetic nervous system activation is influenced by anesthetic agents or cardiovascular drugs during ECT. Pupillary responses can reflect sympathetic nervous activity or the degree of brain damage. Pupillary response measurement can be conducted in a simple, precise, and objective way using an automated infrared pupillometer, enabling the measurement of pupil diameter (mm) to two decimal places. The white light used for measuring light reflexes is not overly bright, and patients do not typically report discomfort. Pupillary light reflexes were measured before anesthesia induction and immediately after electrical stimulation using this equipment. Pupil diameter is typically enlarged after brain damage or sympathetic nervous activation. Adequate seizure induction using ECT could induce pupillary enlargement immediately after electrical stimulation. In the current method, the constriction ratio of pupil size was calculated automatically and compared with seizure quality. Pupillary responses immediately after electrical stimulation may provide a useful assessment of the efficacy of seizure induction with ECT.

Portable pupillometer devices are produced by several companies. These devices are typically conveniently sized and can be operated with one hand (Figure 1A), enabling examiners to accurately detect pupillary responses by pressing a button. Infrared light is used to detect the pupillary edge automatically (Figure 1B), accurately representing pupillary data (Figure 1C). This device m...

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Pupillary Response as Assessment of Effective Seizure Induction by Electroconvulsive Therapy

Pupillary responses (light reflex) were measured for assessment of adequate seizure induction by electroconvulsive therapy using an automated infrared pupillometer immediately after electrical stimulation. Constriction ratio was calculated and compared with seizure quality.

Electroconvulsive therapy (ECT) is reported to be effective for severe neuropsychiatric disorders. In ECT, electrical stimulation is applied to the brain, ...

pupillary-response-as-assessment-effective-seizure-induction

Research

JoVE Journal

Behavior

9.3K Views.  Kyushu University Hospital. De werkzaamheid van ECT, elektroconvulsietherapie, is geëvalueerd op basis van elektro-encefalografie en toename van BP of HR, maar een toenemend aantal patiënten hebben zich aangepast aan ECT en de tarieven van hart- en vaatziekten nemen toe. Aan de andere kant, pupillary reacties kunnen weerspiegelen sympathische nerveuze activiteit of de mate van hersenbeschadiging. Deze voorgestelde methode kan vooral nuttig zijn voor patiënten die tijdens ECT anti-hypertensieve geneesmiddelen hebben t...

Video: Pupillary Response as Assessment of Effective Seizure Induction by Electroconvulsive Therapy

Manipulation of Epileptiform Electrocorticograms (ECoGs) and Sleep in Rats and Mice by Acupuncture

Ancient Chinese literature has documented that acupuncture possesses efficient therapeutic effects on epilepsy and insomnia. There is, however, little research to reveal the possible mechanisms behind these effects. To investigate the effect of acupuncture on epilepsy and sleep, several issues need to be addressed. The first is to identify the acupoints, which correspond between humans, rats, and mice. Furthermore, the depth of insertion of the acupuncture needle, the degree of needle twist in manual needle acupuncture, and the stimulation parameters for electroacupuncture (EA) need to be determined. To evaluate the effects of acupuncture on epilepsy and sleep, a feasible model of epilepsy in rodents is required. We administer pilocarpine into the left central nucleus of the amygdala (CeA) to simulate focal temporal lobe epilepsy (TLE) in rats. Intraperitoneal (IP) injection of pilocarpine induces generalized epilepsy and status epilepticus (SE) in rats. Five IP injections of pentylenetetrazol (PTZ) with a one-day interval between each injection successfully induces spontaneous generalized epilepsy in mice. Recordings of electrocorticograms (ECoGs), electromyograms (EMGs), brain temperature, and locomotor activity are used for sleep analysis in rats, while ECoGs, EMGs, and locomotor activity are employed for sleep analysis in mice. ECoG electrodes are implanted into the frontal, parietal, and contralateral occipital cortices, and a thermistor is implanted above the cerebral cortex by stereotactic surgery. EMG electrodes are implanted into the neck muscles, and an infrared detector determines locomotor activity. The criteria for categorizing vigilance stages, including wakefulness, rapid eye movement (REM) sleep, and non-REM (NREM) sleep are based on information from ECoGs, EMGs, brain temperature, and locomotor activity. Detailed classification criteria are stated in the text.

Manipulation of Epileptiform Electrocorticograms ECoGs and Sleep in Rats and Mice by Acupuncture

This paper demonstrates the performance of acupuncture, epilepsy models, and the analysis of sleep in rodents. The acupuncture procedure and the identification of acupoints are described. Pilocarpine or pentylenetetrazol (PTZ) is used to induce epilepsy. Electrocorticogram (ECoG), electromyogram (EMG), brain temperature, and locomotor activity recordings are employed for sleep analysis.

Ancient Chinese literature has documented that acupuncture possesses efficient therapeutic effects on epilepsy and insomnia. There is, however, little ...

Direct-current Stimulation and Multi-electrode Array Recording of Seizure-like Activity in Mice Brain Slice Preparation

Cathodal transcranial direct-current stimulation (tDCS) induces suppressive effects on drug-resistant seizures. To perform effective actions, the stimulation parameters (e.g., orientation, field strength, and stimulation duration) need to be examined in mice brain slice preparations. Testing and arranging the orientation of the electrode relative to the position of the mice brain slice are feasible. The present method preserves the thalamocingulate pathway to evaluate the effect of DCS on anterior cingulate cortex seizure-like activities. The results of the multichannel array recordings indicated that cathodal DCS significantly decreased the amplitude of the stimulation-evoked responses and duration of 4-aminopyridine and bicuculline-induced seizure-like activity. This study also found that cathodal DCS applications at 15 min caused long-term depression in the thalamocingulate pathway. The present study investigates the effects of DCS on thalamocingulate synaptic plasticity and acute seizure-like activities. The current procedure can test the optimal stimulation parameters including orientation, field strength, and stimulation duration in an in vitro mouse model. Also, the method can evaluate the effects of DCS on cortical seizure-like activities at both the cellular and network levels.

Studies have shown that cathodal transcranial direct-current stimulation can produce suppressive effects on drug-resistant seizures. In this study, an in vitro experimental setup was devised in which the direct-current stimulation and multielectrode array recording of seizure-like activity were evaluated in mice brain slice preparation. The direct-current stimulation parameters were evaluated.

Cathodal transcranial direct-current stimulation (tDCS) induces suppressive effects on drug-resistant seizures. To perform effective actions, the ...

Neuroscience

Non-restraining EEG Radiotelemetry: Epidural and Deep Intracerebral Stereotaxic EEG Electrode Placement

Implantable EEG radiotelemetry is of central relevance in the neurological characterization of transgenic mouse models of neuropsychiatric and neurodegenerative diseases as well as epilepsies. This powerful technique does not only provide valuable insights into the underlying pathophysiological mechanisms, i.e., the etiopathogenesis of CNS related diseases, it also facilitates the development of new translational, i.e., therapeutic approaches. Whereas competing techniques that make use of recorder systems used in jackets or tethered systems suffer from their unphysiological restraining to semi-restraining character, radiotelemetric EEG recordings overcome these disadvantages. Technically, implantable EEG radiotelemetry allows for precise and highly sensitive measurement of epidural and deep, intracerebral EEGs under various physiological and pathophysiological conditions. First, we present a detailed protocol of a straight forward, successful, quick and efficient technique for epidural (surface) EEG recordings resulting in high-quality electrocorticograms. Second, we demonstrate how to implant deep, intracerebral EEG electrodes, e.g., in the hippocampus (electrohippocampogram). For both approaches, a computerized 3D stereotaxic electrode implantation system is used. The radiofrequency transmitter itself is implanted into a subcutaneous pouch in both mice and rats. Special attention also has to be paid to pre-, peri- and postoperative treatment of the experimental animals. Preoperative preparation of mice and rats, suitable anesthesia as well as postoperative treatment and pain management are described in detail.

Non-restraining EEG radiotelemetry is a valuable methodological approach to record in vivo long-term electroencephalograms from freely moving rodents. This detailed protocol describes stereotaxic epidural and deep intracerebral electrode placement in different brain regions in order to obtain reliable recordings of CNS rhythmicity and CNS related behavioral stages.

Implantable EEG radiotelemetry is of central relevance in the neurological characterization of transgenic mouse models of neuropsychiatric and ...

A Multimodal Imaging- and Stimulation-based Method of Evaluating Connectivity-related Brain Excitability in Patients with Epilepsy

Resting-state functional connectivity MRI (rs-fcMRI) is a technique that identifies connectivity between different brain regions based on correlations over time in the blood-oxygenation level dependent signal. rs-fcMRI has been applied extensively to identify abnormalities in brain connectivity in different neurologic and psychiatric diseases. However, the relationship among rs-fcMRI connectivity abnormalities, brain electrophysiology and disease state is unknown, in part because the causal significance of alterations in functional connectivity in disease pathophysiology has not been established. Transcranial Magnetic Stimulation (TMS) is a technique that uses electromagnetic induction to noninvasively produce focal changes in cortical activity. When combined with electroencephalography (EEG), TMS can be used to assess the brain's response to external perturbations. Here we provide a protocol for combining rs-fcMRI, TMS and EEG to assess the physiologic significance of alterations in functional connectivity in patients with neuropsychiatric disease. We provide representative results from a previously published study in which rs-fcMRI was used to identify regions with abnormal connectivity in patients with epilepsy due to a malformation of cortical development, periventricular nodular heterotopia (PNH). Stimulation in patients with epilepsy resulted in abnormal TMS-evoked EEG activity relative to stimulation of the same sites in matched healthy control patients, with an abnormal increase in the late component of the TMS-evoked potential, consistent with cortical hyperexcitability. This abnormality was specific to regions with abnormal resting-state functional connectivity. Electrical source analysis in a subject with previously recorded seizures demonstrated that the origin of the abnormal TMS-evoked activity co-localized with the seizure-onset zone, suggesting the presence of an epileptogenic circuit. These results demonstrate how rs-fcMRI, TMS and EEG can be utilized together to identify and understand the physiological significance of abnormal brain connectivity in human diseases.

Resting-state functional-connectivity MRI has identified abnormalities in patients with a wide range of neuropsychiatric disorders, including epilepsy due to malformations of cortical development. Transcranial Magnetic Stimulation in combination with EEG can demonstrate that patients with epilepsy have cortical hyperexcitability in regions with abnormal connectivity.

Resting-state functional connectivity MRI (rs-fcMRI) is a technique that identifies connectivity between different brain regions based on correlations ...

Medicine

Electroconvulsive Seizures in Rats and Fractionation of Their Hippocampi to Examine Seizure-induced Changes in Postsynaptic Density Proteins

Electroconvulsive seizure (ECS) is an experimental animal model of electroconvulsive therapy, the most effective treatment for severe depression. ECS induces generalized tonic-clonic seizures with low mortality and neuronal death and is a widely-used model to screen anti-epileptic drugs. Here, we describe an ECS induction method in which a brief 55-mA current is delivered for 0.5 s to male rats 200 - 250 g in weight via ear-clip electrodes. Such bilateral stimulation produced stage 4 - 5 clonic seizures that lasted about 10 s. After the cessation of acute or chronic ECS, most rats recovered to be behaviorally indistinguishable from sham &#34;no seizure&#34; rats. Because ECS globally elevates brain activity, it has also been used to examine activity-dependent alterations of synaptic proteins and their effects on synaptic strength using multiple methods. In particular, subcellular fractionation of the postsynaptic density (PSD) in combination with Western blotting allows for the quantitative determination of the abundance of synaptic proteins at this specialized synaptic structure. In contrast to a previous fractionation method that requires large amount of rodent brains, we describe here a small-scale fractionation method to isolate the PSD from the hippocampi of a single rat, without sucrose gradient centrifugation. Using this method, we show that the isolated PSD fraction contains postsynaptic membrane proteins, including PSD95, GluN2B, and GluA2. Presynaptic marker synaptophysin and soluble cytoplasmic protein &#945;-tubulin were excluded from the PSD fraction, demonstrating successful PSD isolation. Furthermore, chronic ECS decreased GluN2B expression in the PSD, indicating that our small-scale PSD fractionation method can be applied to detect the changes in hippocampal PSD proteins from a single rat after genetic, pharmacological, or mechanical treatments.

Electroconvulsive seizure (ECS) is an experimental animal model of electroconvulsive therapy for severe depression. ECS globally stimulates activity in the hippocampus, leading to synaptogenesis and synaptic plasticity. Here, we describe methods for ECS induction in rats and for subcellular fractionation of their hippocampi to examine seizure-induced changes in synaptic proteins.

Electroconvulsive seizure (ECS) is an experimental animal model of electroconvulsive therapy, the most effective treatment for severe depression. ECS ...

Multi-system Monitoring for Identification of Seizures, Arrhythmias and Apnea in Conscious Restrained Rabbits

Patients with ion channelopathies are at a high risk of developing seizures and fatal cardiac arrhythmias. There is a higher prevalence of heart disease and arrhythmias in people with epilepsy (i.e., epileptic heart.) Additionally, cardiac and autonomic disturbances have been reported surrounding seizures. 1:1,000 epilepsy patients/year die of sudden unexpected death in epilepsy (SUDEP). The mechanisms for SUDEP remain incompletely understood. Electroencephalograms (EEG) and electrocardiograms (ECG) are two techniques routinely used in the clinical setting to detect and study the substrates/triggers for seizures and arrhythmias. While many studies and descriptions of this methodology are in rodents, their cardiac electrical activity differs significantly from humans. This article provides a description of a non-invasive method for recording simultaneous video-EEG-ECG-oximetry-capnography in conscious rabbits. As cardiac electrical function is similar in rabbits and humans, rabbits provide an excellent model of translational diagnostic and therapeutic studies. In addition to outlining the methodology for data acquisition, we discuss the analytical approaches for examining neuro-cardiac electrical function and pathology in rabbits. This includes arrhythmia detection, spectral analysis of EEG and a seizure scale developed for restrained rabbits.

Using simultaneous video-EEG-ECG-oximetry-capnography, we developed a methodology to evaluate the susceptibility of rabbit models to develop provoked arrhythmias and seizures. This novel recording system establishes a platform to test the efficacy and safety of therapeutics and can capture the complex cascade of multi-system events that culminate in sudden death.

Patients with ion channelopathies are at a high risk of developing seizures and fatal cardiac arrhythmias. There is a higher prevalence of heart disease ...

Integrating MEG and HD-EEG in Pediatric Epilepsy Localization

Electromagnetic Source Imaging in Presurgical Evaluation of Children with Drug-Resistant Epilepsy

For children with drug-resistant epilepsy (DRE), seizure freedom relies on the delineation and resection (or ablation/disconnection) of the epileptogenic zone (EZ) while preserving the eloquent brain areas. The development of a reliable and noninvasive localization method that provides clinically useful information for the localization of the EZ is, therefore, crucial to achieving successful surgical outcomes. Electric and magnetic source imaging (ESI and MSI) have been increasingly utilized in the presurgical evaluation of these patients showing promising findings in the delineation of epileptogenic as well as eloquent brain areas. Moreover, the combination of ESI and MSI into a single solution, namely electromagnetic source imaging (EMSI), performed on simultaneous high-density electroencephalography (HD-EEG) and magnetoencephalography (MEG) recordings has shown higher source localization accuracy than either modality alone. Despite these encouraging findings, such techniques are performed in only a few tertiary epilepsy centers, are rarely recorded simultaneously, and are underutilized in pediatric cohorts. This study illustrates the experimental setup for recording simultaneous MEG and HD-EEG data as well as the methodological framework for analyzing these data aiming to localize the irritative zone, the seizure onset zone, and eloquent brain areas in children with DRE. More specifically, the experimental setups are presented for (i) recording and localizing interictal and ictal epileptiform activity during sleep and (ii) recording visual-, motor-, auditory-, and somatosensory-evoked responses and mapping relevant eloquent brain areas (i.e., visual, motor, auditory, and somatosensory) during visuomotor task, as well as auditory and somatosensory stimulations. Detailed steps of the data analysis pipeline are further presented for performing EMSI as well as individual ESI and MSI using equivalent current dipole (ECD) and dynamic statistical parametric mapping (dSPM).

Author Spotlight: Advancing Pediatric Epilepsy Surgery in Children Through Novel Biomarkers and Enhanced Localization

Magnetoencephalography (MEG) and high-density electroencephalography (HD-EEG) are rarely recorded simultaneously, although they yield confirmatory and complementary information. Here, we illustrate the experimental setup for recording simultaneous MEG and HD-EEG and the methodology for analyzing these data aiming to localize epileptogenic and eloquent brain areas in children with drug-resistant epilepsy.

For children with drug-resistant epilepsy (DRE), seizure freedom relies on the delineation and resection (or ablation/disconnection) of the epileptogenic ...

Intermittent Photic Stimulation in Rabbit Model: A Technique to Induce Epileptic Seizures and Simultaneously Record Multisystem Parameters

Source: Bosinski, C., et al. <a href="https://www.jove.com/v/62256">Multi-system Monitoring for Identification of Seizures, Arrhythmias and Apnea in Conscious Restrained Rabbits.</a> J. Vis. Exp. (2021).
In this video, we show a procedure for simultaneous recording of video-EEG-ECG-capnography-oximetry data generated by inducing seizures in a rabbit model.

Source: Bosinski, C., et al. Multi-system Monitoring for Identification of Seizures, Arrhythmias and Apnea in Conscious Restrained Rabbits. J. Vis. Exp. ...

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Biology

Large Animal Models

Leporine

Multisystem Monitoring of Epileptic Abnormalities in Rabbit: A Method for Simultaneous Video EEG, ECG, Capnography, and Oximetry Recording During Induced Seizures

Source: Bosinski, C., et al. <a href="https://www.jove.com/v/62256">Multi-system Monitoring for Identification of Seizures, Arrhythmias and Apnea in Conscious Restrained Rabbits.</a> J. Vis. Exp. (2021).
In this video, we demonstrate a multisystem monitoring method to evaluate neurological and cardiorespiratory abnormalities during intravenous injection of a seizure-inducing drug. The simultaneous monitoring of video EEG, ECG, oximetry, and capnography parameters helps to understand the real-time physiological changes associated with epileptic seizures.

Monitoring the Brain Cortex with a Multi-Electrode Array in Response to Seizure-Inducing Agents

Source: Lu, H. C., et al. <a href="https://app.jove.com/v/53709">Direct-current stimulation and multi-electrode array recording of seizure-like activity in mice brain slice preparation.</a> J. Vis. Exp. (2016).
In this video, the effects of transcranial direct-current stimulation (tDCS) on brain slices containing the anterior cingulate cortex (ACC) and thalamus regions are investigated, using a multi-electrode array (MEA) to measure electric signals. By delivering electric pulses and infusing seizure-inducing drugs, the study investigates the ACC response to seizures.

All procedures involving animal samples have been reviewed and approved by the appropriate animal ethical review committee.
1. Preparing Experimental ...

Pupillary Response as Assessment of Effective Seizure Induction by Electroconvulsive Therapy

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