Spontaneous Discharge Research Articles

P341 Painful legs and moving toes syndrome associated with peripheral nerve hyperexcitability and central nervous system involvement

Objectives We report a 68-year-old male patient referred for an electromyography (EMG). The patient’s clinical picture was compatible with a Painful Legs and Moving Toes (PLMT) syndrome, with added symptoms of forgetfulness, confusion and somniloquy of four-year course. He had been previously treated as a Restless Legs Syndrome without any improvement. Methods We performed a neurophysiological exam including nerve conduction study, needle EMG, somatosensory-evoked potentials, repetitive nerve stimulation for the assessment of peripheral nerve hiperexcitability (PNH), and surface EMG recording during wakefulness and sleep. Results Nerve conduction study and somatosensory-evoked potentials documented no abnormalities. The EMG was also normal except for cramps and fasciculations in abductor hallucis and some fasciculations in gastrocnemius. Afterdischarges were recorded after repetitive nerve stimulation of median and tibial nerves. Surface EMG recording of leg muscles showed bursts of spontaneous activity and discharges lasting more than 10 s, whose larger amplitudes corresponded with increased pain. Radiological tests documented no underlying causes. Discussion and conclusions PLMT is a rare movement disorder characterized by leg pain and involuntary movement of toes. It is believed that the symptomatology can be generated both peripherally and centrally. Hence, there is no agreement on PLMT treatment and response to drugs is usually poor. We report a case of idiopathic PLMT with neurophysiological evidence of PNH and central nervous system symptomatology. Significance The whole clinical and electrophysiological picture suggests a nervous system dysfunction with both central involvement and PNH not yet described as a cause of PLMT.

On a unified point process approach for the characterization of bioelectric discrete phenomena.

This paper discusses a unified method based on the theory of point processes to characterize various types of bioelectric discrete signals such as heart beat timing, myoelectric activity, discharge of primary sensory neurons or neurons in the central nervous systems. The doubly stochastic point processes, in which the discrete event occurring intensity is stochastic, forms the most general class to characterize the discrete phenomena. In this paper the self-exciting process has been shown to be useful to characterize wide range of discrete biosignals. The modeling of conditional intensity function is the essential part of the characterization. When the intensity has a parametric model, the maximum likelihood parameter estimation will be the useful way to characterize the phenomena. The effectiveness of the method is demonstrated by a specific modeling of the spontaneous neuronal burst discharges recorded from the brain thalamus during the neuro surgery. The first approximation model has four parameters obtained by the instantaneous nonlinearly transformed sinusoidal function. An extended model allows arbitrary periodic intensity with refractory period. Predicted interval histograms show good agreement with the observed ones indicating the validity of the proposed method.

Analysis of epidemiological, clinical and therapeutic aspects. Epilepsy with absence seizures (EAS)

Objective: To analyse the epidemiological, clinical and therapeutic aspects of EAS to identify possible prognostic factors. Patients and methods: Retrospective descriptive study from January 2009 to December 2015 of patients <14 years diagnosed of epilepsy with EAS in a referral Centre. Results: We identified 42 cases; 34/42 were childhood absences epilepsy (CAE) and 8/42 were juvenile absence epilepsys (JAE). Mean time until diagnose after onset of symptoms was 6 months, with the majority (37/42) showing multiple daily seizuresattacks. EEG showed found 3 Hz generalized spike-and-wave (GSW) discharges in all cases with a mean duration of 10.2 s in CAE and 5 s in JAE with additional paroxysm in 12/42 (4/12 bifrontal,3/12 frontotemporal,2/12 biparietal and 3/13 temporal). Valproic acid was started in 39/42 and ethosuximide associated in 9/42 refractory cases. Refractory patients presented with spontaneous GSW discharges in 7/9 occasions in the EEG, with a mean duration of 14.7 s. Temporal paroxysms was found in 3/9. Mean time until diagnose was 8.5 months. Myoclonic seizures were present in 1/34 of CAE cases, tonic clonic seizures in 8/34 versus 4/8 of the JAE cases. Refractory crisis were present at 2 years in 3/42 cases, relapses in 4/42 cases, of which 3/4 did not reach optimal school level. Conclusions: We observed that a time until diagnose greater than 9 months, spontaneous 3 Hz GSW, duration of discharges greater than 15 s as well as temporal paroxysms were related to poor response to treatment. It is advisable to increase the study population to draw solid conclusions.

3-2-01. Decreased motor axonal potassium currents in peripheral nerve hyperexcitability syndrome with negativity for anti-VGKC antibody and positivity for anti-CRMP5 antibody

Peripheral nerve hyperexcitability (PNH) syndromes are caused by spontaneous discharges originating from motor axons. Antibodies against voltage-gated potassium channels (VGKC) are detected in some patients with PNH syndrome, but the cause in the remaining patients has not yet been clarified. The index patient was a 46-year-old female with recurred thymoma and myasthenia gravis. Six month after the start of chemotherapy, she developed myokymia, fasciculations and muscle cramps in both her lower limbs. A nerve conduction studies revealed mild axonal polyneuropathy and a motor F-wave examination showed marked after-discharges. Needle electromyography showed fasciculation potentials and myokymic discharges. From these results, the patient was diagnosed with PNH syndrome. Nerve excitability study showed extremely greater supernormality in the recovery cycle and greater changes in depolarizing threshold electrotonus than control, suggesting decreased slow potassium currents in the motor axons. Serological tests revealed the absence of anti-VGKC antibody and the presence of anti-collapsin response mediator protein 5 (CRMP5) antibody. A recent study reported that CRMP5 plays an important role in axon–Schwann cell cooperation during development and nerve regeneration. The coexistence of nerve regeneration and anti-CRMP5 antibody may cause abnormal axon–Schwann cell interaction, which would result in slow potassium channel dysfunction and associated symptoms such as myokymia.

Cervical vagus nerve stimulation augments spontaneous discharge in second- and higher-order sensory neurons in the rat nucleus of the solitary tract.

Vagus nerve stimulation (VNS) currently treats patients with drug-resistant epilepsy, depression, and heart failure. The mild intensities used in chronic VNS suggest that primary visceral afferents and central nervous system activation are involved. Here, we measured the activity of neurons in the nucleus of the solitary tract (NTS) in anesthetized rats using clinically styled VNS. Our chief findings indicate that VNS at threshold bradycardic intensity activated NTS neuron discharge in one-third of NTS neurons. This VNS directly activated only myelinated vagal afferents projecting to second-order NTS neurons. Most VNS-induced activity in NTS, however, was unsynchronized to vagal stimuli. Thus, VNS activated unsynchronized activity in NTS neurons that were second order to vagal afferent C-fibers as well as higher-order NTS neurons only polysynaptically activated by the vagus. Overall, cardiovascular-sensitive and -insensitive NTS neurons were similarly activated by VNS: 3/4 neurons with monosynaptic vagal A-fiber afferents, 6/42 neurons with monosynaptic vagal C-fiber afferents, and 16/21 polysynaptic NTS neurons. Provocatively, vagal A-fibers indirectly activated C-fiber neurons during VNS. Elevated spontaneous spiking was quantitatively much higher than synchronized activity and extended well into the periods of nonstimulation. Surprisingly, many polysynaptic NTS neurons responded to half the bradycardic intensity used in clinical studies, indicating that a subset of myelinated vagal afferents is sufficient to evoke VNS indirect activation. Our study uncovered a myelinated vagal afferent drive that indirectly activates NTS neurons and thus central pathways beyond NTS and support reconsideration of brain contributions of vagal afferents underpinning of therapeutic impacts.NEW & NOTEWORTHY Acute vagus nerve stimulation elevated activity in neurons located in the medial nucleus of the solitary tract. Such stimuli directly activated only myelinated vagal afferents but indirectly activated a subpopulation of second- and higher-order neurons, suggesting that afferent mechanisms and central neuron activation may be responsible for vagus nerve stimulation efficacy.

Diagnostic value of endoscopic appearance during ductoscopy in patients with pathological nipple discharge

BackgroundTo explore the features of ductoscopic appearance that may be diagnostic in patients with pathologic nipple discharge (PND) and to discuss the diagnostic criteria for intraductal tumors.MethodsWe reviewed 247 patients with PND but without a palpable mass who were evaluated using either surgical biopsy or excision. Data concerning patient age, duration of discharge, discharge color, and the details of endoscopic appearance were analyzed according to the pathological results.ResultsThe postoperative diagnosis in 61 patients (24.70%) was a nonmass lesion, and 186 patients (76.52%) had an intraductal tumor. Among those with intraductal lesions, 10 patients (4.05%) had a malignant tumor, including 4 (1.62%) with ductal carcinoma in situ and 6 (2.43%) with invasive ductal carcinoma. On univariate analysis, patients of older age with spontaneous and bloody discharge were more likely to suffer from intraductal lesions. On logistic regression analysis, bloody nipple discharge, morphology, and a broad lesion base revealed by ductoscopy showed a statistically significant correlation with malignancy (p = 0.001, p < 0.001, p = 0.022, respectively).ConclusionsBoth clinical features and endoscopic appearance are significant for the precise diagnosis of an intraductal lesion seen on ductoscopy. The endoscopic features of bloody discharge, morphology, and a broad lesion base are independent risk factors for malignancy and represent new criteria for the diagnosis of patients with PND.

Spatial Gradients in the Size of Inner Hair Cell Ribbons Emerge Before the Onset of Hearing in Rats.

The size and locations of pre-synaptic ribbons and glutamate receptors within and around inner hair cells are correlated with auditory afferent response features such as the spontaneous discharge rate (SR), threshold, and dynamic range of sound intensity representation (the so-called SR-groups). To test if the development of these spatial gradients requires experience with sound intensity, we quantified the size and spatial distribution of synaptic ribbons from the inner hair cells of neonatal rats before and after the onset of hearing (from post-natal day (P) 3 to P33). To quantify ribbon size, we used high resolution fluorescence confocal microscopy and 3-D reconstructions of immunolabeled ribbons. The size, density, and spatial distribution of ribbons changed during development. At P3, ribbons were densely clustered near the basal/modiolar face of the hair cell where low SR-groups preferentially contact adult hair cells. By P12, the disparity in ribbon count was less striking and ribbons were equally likely to occupy both faces. At all ages before P12, ribbons were larger on the modiolar face than on the pillar face. These differences initially grew larger with age but collapsed around the onset of hearing. Between P12 and P33, the spatial gradients remained small and began to re-emerge around P33. Even by P12, we did not find spatial gradients in the size of the post-synaptic glutamate receptors as is found on afferent terminals contacting adult inner hair cells. These results suggest that spatial gradients in ribbon size develop in the absence of sensory experience.

Diagnosis of Nipple Discharge: Value of Magnetic Resonance Imaging and Ultrasonography in Comparison with Ductoscopy.

Background:Pathologic nipple discharge, which is a common reason for referral to the breast imaging service, refers to spontaneous or bloody nipple discharge that arises from a single duct. The most common cause of nipple discharge is benign breast lesions, such as solitary intraductal papilloma and papillomatosis. Nevertheless, in rare cases, a malignant cause of nipple discharge can be found.Aims:To study the diagnostic value of ultrasonography, magnetic resonance imaging, and ductoscopy in patients with pathologic nipple discharge, compare their efficacy, and investigate the importance of magnetic resonance imaging in the diagnosis of intraductal pathologies.Study Design:Diagnostic accuracy study.Methods:Fifty patients with pathologic nipple discharge were evaluated by ultrasonography and magnetic resonance imaging. Of these, 44 ductoscopic investigations were made. The patients were classified according to magnetic resonance imaging, ultrasonography, and ductoscopy findings. A total of 25 patients, whose findings were reported as intraductal masses, underwent surgery oincluding endoscopic excision for two endoscopic excision. Findings were compared with the pathology results that were accepted as the gold standard in the description of the aetiology of nipple discharge. In addition, magnetic resonance imaging, ultrasonography and ductoscopy findings were analysed comparatively in patients who had no surgery.Results:Intraductal masses were reported in 26 patients, 20 of whom operated and established accurate diagnosis of 18 patients on magnetic resonance imaging. According to the ultrasonography, intraductal masses were identified in 22 patients, 17 of whom underwent surgery. Ultrasonography established accurate diagnoses in 15 patients. Intraductal mass was identified in 22 patients and ductoscopy established accurate diagnoses based on histopathologic results in 16 patients. The sensitivities of methods were 75% in ultrasonography, 90% in magnetic resonance imaging, and 94.6% in ductoscopy. The specificities were 66.7% in ultrasonography, 66.7% in magnetic resonance imaging, and 40% in ductoscopy. Intraductal papillomas were mostly observed as oval nodules with well-circumscribed smooth margins within dilated ducts and persistant in the dynamic analysis. Lesions that protruded into the lumen of the ducts, either solitary or multiple, were characteristic ductoscopy findings of our patients who were diagnosed as having papilloma/papillomatosis.Conclusion:Magnetic resonance imaging and ductoscopy had no statistical superiority over each other, however they were superior to ultrasonography in the diagnosis of pathologic nipple discharge. Magnetic resonance imaging may be highly sensitive for diagnosing nipple discharge with new techniques and sequences and a non-invasive method that more advantageous for showing ductal tree visualization and is able to detect completely obstructed intraductal lesions.

The medullary dorsal reticular nucleus as a relay for descending pronociception induced by the mGluR5 in the rat infralimbic cortex

Metabotropic glutamate receptor 5 (mGluR5) activation in the infralimbic cortex (IL) induces pronociceptive behavior in healthy and monoarthritic rats. Here we studied whether the medullary dorsal reticular nucleus (DRt) and the spinal TRPV1 are mediating the IL/mGluR5-induced spinal pronociception and whether the facilitation of pain behavior is correlated with changes in spinal dorsal horn neuron activity. For drug administrations, all animals had a cannula in the IL as well as a cannula in the DRt or an intrathecal catheter. Heat-evoked paw withdrawal was used to assess pain behavior in awake animals. Spontaneous and heat-evoked discharge rates of single DRt neurons or spinal dorsal horn wide-dynamic range (WDR) and nociceptive-specific (NS) neurons were evaluated in lightly anesthetized animals.Activation of the IL/mGluR5 facilitated nociceptive behavior in both healthy and monoarthritic animals, and this effect was blocked by lidocaine or GABA receptor agonists in the DRt. IL/mGluR5 activation increased spontaneous and heat–evoked DRt discharge rates in healthy but not monoarthritic rats. In the spinal dorsal horn, IL/mGluR5 activation increased spontaneous activity of WDR neurons in healthy animals only, whereas heat-evoked responses of WDR and NS neurons were increased in both experimental groups. Intrathecally administered TRPV1 antagonist prevented the IL/mGluR5-induced pronociception in both healthy and monoarthritic rats.The results suggest that the DRt is involved in relaying the IL/mGluR5-induced spinal pronociception in healthy control but not monoarthritic animals. Spinally, the IL/mGluR5-induced behavioral heat hyperalgesia is mediated by TRPV1 and associated with facilitated heat-evoked responses of WDR and NS neurons.

Optogenetic activation of VGLUT2-expressing excitatory neurons blocks epileptic seizure-like activity in the mouse entorhinal cortex

We investigated whether an anti-epileptic effect is obtained by selectively activating excitatory neurons expressing ChR2 under the promoter for the synaptic vesicular glutamate transporter 2 (VGLUT2). VGLUT2-expressing cells were optically stimulated while local field potential and whole-cell patch-clamp recordings were performed in mouse entorhinal cortical slices perfused with the proconvulsive compound 4-aminopyridine (4-AP). In control conditions, blue light flashes directly depolarized the majority of putative glutamatergic cells, which in turn synaptically excited GABAergic interneurons. During bath perfusion with 4-AP, photostimuli triggered a fast EPSP-IPSP sequence which was often followed by tonic-clonic seizure-like activity closely resembling spontaneous ictal discharges. The GABAA-receptor antagonist gabazine blocked the progression of both light-induced and spontaneous seizures. Surprisingly, prolonged photostimuli delivered during ongoing seizures caused a robust interruption of synchronous discharges. Such break was correlated with a membrane potential depolarization block in principal cells, while putative GABAergic interneurons changed their firing activity from a burst-like to an irregular single-spike pattern. These data suggest that photostimulation of glutamatergic neurons triggers seizure-like activity only in the presence of an intact GABAergic transmission and that selectively activating the same glutamatergic cells robustly interrupts ongoing seizures by inducing a strong depolarization block, resulting in the disruption of paroxysmal burst-like firing.

Cortical spreading depolarizations in the postresuscitation period in a cardiac arrest male rat model

Neurological injury develops over days following cardiac arrest (CA); however, the exact mechanisms remain unknown. After stroke or trauma, the progression of neurological injury is associated with cortical-spreading depolarizations (CSDs). The objective was to investigate whether CA and subsequent resuscitation in rats are associated with 1) the development of spontaneous negative direct current (DC) shifts indicative of CSDs, and 2) changes in artificially induced CSDs in the postresuscitation period. Male Sprague-Dawley rats were randomized into four groups: 1) CA 90, 2) Control 90, 3) CA 360, and 4) Control 360. Following 8 min of asphyxial CA, animals were resuscitated using adrenaline, ventilation, and chest compressions. Animals were observed for 90 or 360 min, respectively, before a 210-min data collection period. Cortical potentials were recorded through burr holes over the right hemisphere. Animals were intubated and monitored with invasive blood pressure, ECG, and arterial blood gas samples throughout the study. Spontaneous DC shifts occurred in only 1 of the 14 CA animals. In control animals, DC shifts were easy to induce, and their shape was highly uniform, consistent with that of classical CSDs. In CA animals, significantly fewer DC shifts could be induced, and their shape was profoundly altered compared with controls. We observed frequent epileptiform discharges and temporal clusters of activity. Spontaneous CSDs were not a consistent finding in CA animals. Instead, spontaneous epileptiform discharges and temporal cluster of activity were observed, while the shapes of induced DC shifts were profoundly altered compared with controls. © 2017 Wiley Periodicals, Inc.

ProNGF Drives Localized and Cell Selective Parvalbumin Interneuron and Perineuronal Net Depletion in the Dentate Gyrus of Transgenic Mice.

ProNGF, the precursor of mature Nerve Growth Factor (NGF), is the most abundant NGF form in the brain and increases markedly in the cortex in Alzheimer's Disease (AD), relative to mature NGF. A large body of evidence shows that the actions of ProNGF and mature NGF are often conflicting, depending on the receptors expressed in target cells. TgproNGF#3 mice, expressing furin-cleavage resistant proNGF in CNS neurons, directly reveal consequences of increased proNGF levels on brain homeostasis. Their phenotype clearly indicates that proNGF can be a driver of neurodegeneration, including severe learning and memory behavioral deficits, cholinergic deficits, and diffuse immunoreactivity for A-beta and A-beta-oligomers. In aged TgproNGF#3 mice spontaneous epileptic-like events are detected in entorhinal cortex-hippocampal slices, suggesting occurrence of excitatory/inhibitory (E/I) imbalance. In this paper, we investigate the molecular events linking increased proNGF levels to the epileptiform activity detected in hippocampal slices. The occurrence of spontaneous epileptiform discharges in the hippocampal network in TgproNGF#3 mice suggests an impaired inhibitory interneuron homeostasis. In the present study, we detect the onset of hippocampal epileptiform events at 1-month of age. Later, we observe a regional- and cellular-selective Parvalbumin interneuron and perineuronal net (PNN) depletion in the dentate gyrus (DG), but not in other hippocampal regions of TgproNGF#3 mice. These results demonstrate that, in the hippocampus, the DG is selectively vulnerable to altered proNGF/NGF signaling. Parvalbumin interneuron depletion is also observed in the amygdala, a region strongly connected to the hippocampus and likewise receiving cholinergic afferences. Transcriptome analysis of TgproNGF#3 hippocampus reveals a proNGF signature with broad down-regulation of transcription. The most affected mRNAs modulated at early times belong to synaptic transmission and plasticity and extracellular matrix (ECM) gene families. Moreover, alterations in the expression of selected BDNF splice variants were observed. Our results provide further mechanistic insights into the vicious negative cycle linking proNGF and neurodegeneration, confirming the regulation of E/I homeostasis as a crucial mediating mechanism.

Intraoperative electrocorticography

AbstractIntraoperative electrocorticography (ECoG) is the recording of electrophysiological activity from electrodes placed directly on the exposed surface of brain, during surgery for epilepsy and tumor resection. The ECoG is helpful in defining the seizure onset and spread within the cortical surface and delineation of the interface between epileptogenic zones and functional cortex substance of the brain. Intraoperative ECoG is an invasive procedure, it is performed during surgery mostly commonly during awake craniotomy but at times during general anaesthesia. As most anesthetic agents will affect ECoG, they should be minimized or stopped prior to any recording. Activation of intraoperative epileptiform activity may also be required if there are no spontaneous discharges. The appropriate management of the anesthetic during the time of ECoG is critical for its success. There are limitations and some controversies to all the uses of intraoperative ECoG, thus each center will set their own indications, criteria, and protocols.

Peripheral and central administration of T3 improved the histological changes, memory and the dentate gyrus electrophysiological activity in an animal model of Alzheimer's disease.

The amyloid beta (Aβ) induced Alzheimer's disease (AD) is associated with formation the amyloid plaques, cognitive impairments and decline in spontaneous discharge of neurons. In the current study, we evaluated the effect of subcutaneous (S. C) and intrahippocampal (I. H) administrations of triiodothyronine (T3) on the histological changes, memory and the dentate gyrus (DG) electrophysiological activity in an animal model of AD. Eighty adult male Wistar rats (250-300g) were divided randomly into five groups: Sham-Operated (Sh-O), AD+Vehicle (S. C), AD+Vehicle (I. H), AD+ T3 (S. C) and AD+T3 (I. H). In order to induce animal model of AD, Aβ (10ng/μl, bilaterally) were injected intrahippocampally. Rats were treated with T3 and/or normal saline for 10days. Passive avoidance and spatial memory were evaluated in shuttle box apparatus and Morris water maze, respectively. Neuronal single unit recording was assessed from hippocampal DG. The percent of total time that animals spent in target quarter, the mean latency time (sec), the step through latency and the average number of spikes/bin were decreased significantly in AD rats compared with the Sh-O group (p<0.001) and were increased significantly in AD groups that have received T3 (S. C and I. H) in compared with AD group (p<0.01, p<0.001). Also, formation of amyloid plaques was decreased in AD rats treated with T3.The results showed that T3 injection (S. C and I. H), by reduction of neural damage and increment of neuronal spontaneous activity improved the memory deficits in Aβ-induced AD rats.

Corticotropin releasing factor dose-dependently modulates excitatory synaptic transmission in the noradrenergic nucleus locus coeruleus.

The noradrenergic nucleus locus coeruleus (LC) is critically involved in the stress response and receives afferent input from a number of corticotropin releasing factor (CRF) containing structures. Several invivo and invitro studies in rat have shown that CRF robustly increases the firing rate of LC neurons in a dose-dependent manner. While it is known that these increases are dependent on CRF receptor subtype 1 and mediated by effects of cAMP intracellular signaling cascades on potassium conductance, the impact of CRF on synaptic transmission within LC has not been clarified. In the present study, we used whole-cell patch clamp electrophysiology to assess how varying concentrations of bath-applied CRF affect AMPA-receptor dependent spontaneous excitatory post-synaptic currents (sEPSCs). Compared to vehicle, 10, 25, and 100nm CRF had no significant effects on any sEPSC parameters. Fifty nanomolar CRF, however, significantly increased sEPSC amplitude, half-width, and charge transfer, while these measures were significantly decreased by 200nm CRF. These observations suggest that stress may differentially affect ongoing excitatory synaptic transmission in LC depending on how much CRF is released from presynaptic terminals. Combined with the well-documented effects of CRF on membrane properties and spontaneous LC discharge, these observations may help explain how stress and CRF release are able to modulate the signal to noise ratio of LC neurons. These findings have implications for how stress affects the fidelity of signal transmission and information flow through LC and how it might impact norepinephrine release in the CNS.

Mammary duct ectasia with bloody nipple discharge in a 5-month-old infant: A case report

Abstract Mammary ductal ectasia (MDE) with bloody nipple discharge (BND) appears to be exceptionally rare and presents a challenge for management to the consulting physician. We report A 5-month-old boy presented with a 3 weeks history of unilateral breast enlargement associated with intermittent spontaneous bloody nipple discharge. Ultrasound evaluation showed a 1.0 cm × 0.57 cm cystic mass in the right subareolar region with dilated ducts. Cytological evaluation of nipple discharge showed no malignant cells. The breast swelling and nipple discharge resolved spontaneously after 1 months without recurrence during the following 7 months. We conclude that mammary ductal ectasia is a benign and self-limited disorder in infancy and can be manged conservatively without any specific treatment to avoid unnecessary invasive surgical intervention.

Long-Lasting Visuo-Vestibular Mismatch in Freely-Behaving Mice Reduces the Vestibulo-Ocular Reflex and Leads to Neural Changes in the Direct Vestibular Pathway.

Calibration of the vestibulo-ocular reflex (VOR) depends on the presence of visual feedback. However, the cellular mechanisms associated with VOR modifications at the level of the brainstem remain largely unknown. A new protocol was designed to expose freely behaving mice to a visuo-vestibular mismatch during a 2-week period. This protocol induced a 50% reduction of the VOR. In vivo pharmacological experiments demonstrated that the VOR reduction depends on changes located outside the flocculus/paraflocculus complex. The cellular mechanisms associated with the VOR reduction were then studied in vitro on brainstem slices through a combination of vestibular afferent stimulation and patch-clamp recordings of central vestibular neurons. The evoked synaptic activity demonstrated that the efficacy of the synapses between vestibular afferents and central vestibular neurons was decreased. In addition, a long-term depression protocol failed to further decrease the synapse efficacy, suggesting that the VOR reduction might have occurred through depression-like mechanisms. Analysis of the intrinsic membrane properties of central vestibular neurons revealed that the synaptic changes were supplemented by a decrease in the spontaneous discharge and excitability of a subpopulation of neurons. Our results provide evidence that a long-lasting visuo-vestibular mismatch leads to changes in synaptic transmission and intrinsic properties of central vestibular neurons in the direct VOR pathway. Overall, these results open new avenues for future studies on visual and vestibular interactions conducted in vivo and in vitro.

Hematohidrosis: A rare case of a female child who sweat blood

Hematohidrosis is a rare clinical entity characterized by excretion of blood in the sweat. Hematohidrosis presents as unpredictable, recurrent episodes of spontaneous and self-limited bloody discharge from the intact skin. Diagnosis of hematohidrosis is confirmed by testing the secretions for the presence of blood components. It is an extremely rare condition, with very few case reports in literature. Herein, we describe a case of hematohidrosis in an 11-year-old female child with pain and tenderness who responded to propranolol.

Wireless telemetry as an ideal tool for continuous intrahippocampal EEG recording in chronic epilepsy mouse models

Event Abstract Back to Event Wireless telemetry as an ideal tool for continuous intrahippocampal EEG recording in chronic epilepsy mouse models Yana Van Den Herrewegen1*, An Buckinx1*, Gino De Smet1, Ilse J. Smolders1 and Dimitri De Bundel1 1 Vrije Universiteit Brussel, Experimental Pharmacology (EFAR), cluster Neurosciences, Belgium Tethered recording systems are routinely used as a method for long-term continuous EEG monitoring in animal models of epilepsy. Nevertheless, tethered systems display some disadvantages when chronically used in mice, in some cases even compromising experiments and behavioral follow-up of the mice. Therefore, wireless telemetry systems are increasingly being used as an alternative method to precisely measure biopotentials in the rodent brain. As EEG recordings are the most powerful read-outs in animal models of epilepsy, we evaluated the use of wireless radio-telemetry in the intrahippocampal post-status epilepticus kainic acid model, an established mouse model for studying temporal lobe epilepsy and epileptogenesis. Via intraperitoneal implantation of a radiofrequency transmitter (ETA-F10, DSI) and electrodes positioned in the hippocampus, we were able to record intrahippocampal signals for up to two months. We could clearly monitor the epileptic activity during the status epilepticus, followed by a short latent period and the subsequent occurrence of the typical spontaneous epileptic discharges. This study discusses the advantages of telemetric EEG recordings and strategies to maximize the signal-to-noise ratio in order to obtain high-quality deep-brain EEG recordings. In conclusion, wireless telemetry systems are a valuable EEG monitoring method in the intrahippocampal kainic acid mouse model and other models of chronic epilepsy in mice. References Bouilleret V, Ridoux V, Depaulis A, et al. Recurrent seizures and hippocampal sclerosis following intrahippocampal kainate injection in adult mice: electroencephalography, histopathology and synaptic reorganization similar to mesial temporal lobe epilepsy. Neuroscience. 1999; Mar;89(3):717-29. Duveau V, Pouyatos B, Bressand K, et al. Differential Effects of Antiepileptic Drugs on Focal Seizures in the Intrahippocampal Kainate Mouse Model of Mesial Temporal Lobe Epilepsy. CNS Neuroscience & Therapeutics: CNS Neurosci Ther. 2016;(22):497-50. doi: 10.1111/cns.12523 Lundt A, Wormuth C, Siwek ME, et al. EEG Radiotelemetry in Small Laboratory Rodents: A Powerful State-of-the Art Approach in Neuropsychiatric, Neurodegenerative, and Epilepsy Research. Neural Plasticity. 2016;2016:8213878. doi:10.1155/2016/8213878. Twele F, Tollner K, Bankstahl M, Loscher W, et al. The effects of carbamazepine in the intrahippocampal kainate model of temporal lobe epilepsy depend on seizure definition and mouse strain. Epilepsia Open, 2016; 1(1):45–60,. doi: 10.1002/epi4.2 Zayachkivsky A, Lehmkuhle MJ, Dudek FE. Long-term Continuous EEG Monitoring in Small Rodent Models of Human Disease Using the Epoch Wireless Transmitter System. Journal of Visualized Experiments : JoVE. 2015;(101):52554. doi:10.3791/52554. Keywords: wireless radio-telemetry, EEG, Epilepsy, Temporal Lobe, mouse models, Seizures Conference: 12th National Congress of the Belgian Society for Neuroscience, Gent, Belgium, 22 May - 22 May, 2017. Presentation Type: Poster Presentation Topic: Novel Methods and Technology Development Citation: Van Den Herrewegen Y, Buckinx A, De Smet G, Smolders IJ and De Bundel D (2019). Wireless telemetry as an ideal tool for continuous intrahippocampal EEG recording in chronic epilepsy mouse models. Front. Neurosci. Conference Abstract: 12th National Congress of the Belgian Society for Neuroscience. doi: 10.3389/conf.fnins.2017.94.00001 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 02 May 2017; Published Online: 25 Jan 2019. * Correspondence: Miss. Yana Van Den Herrewegen, Vrije Universiteit Brussel, Experimental Pharmacology (EFAR), cluster Neurosciences, Brussels, 1090, Belgium, yana.van.den.herrewegen@vub.ac.be Miss. An Buckinx, Vrije Universiteit Brussel, Experimental Pharmacology (EFAR), cluster Neurosciences, Brussels, 1090, Belgium, an.buckinx@vub.be Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Yana Van Den Herrewegen An Buckinx Gino De Smet Ilse J Smolders Dimitri De Bundel Google Yana Van Den Herrewegen An Buckinx Gino De Smet Ilse J Smolders Dimitri De Bundel Google Scholar Yana Van Den Herrewegen An Buckinx Gino De Smet Ilse J Smolders Dimitri De Bundel PubMed Yana Van Den Herrewegen An Buckinx Gino De Smet Ilse J Smolders Dimitri De Bundel Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Charging and Discharging Channels in Photoluminescence Intermittency of Single Colloidal CdSe/CdS Core/Shell Quantum Dot.

Understanding photoluminescence (PL) intermittency of single quantum dots (QDs) (intensity blinking by randomly switching between distinguishable brightness states under continuous excitation) has been a long-standing fundamental challenge and potential roadblock for their applications. Here we introduce a new analysis method for single-molecule spectroscopy that treats the blinking as photochemical/chemical processes (switching between neutral/bright and charged/dim states). It uncovers the channels for charging (bright to dim) and discharging (dim to bright) involved in PL blinking of single CdSe/CdS core/shell QDs. Both charging and discharging of the single CdSe/CdS core/shell QD possess a photochemical channel (∼10-5 to 10-6 events/photon) that linearly depends on excitation in both single- and multi-exciton regime. These two linear channels coupled to a spontaneous discharging channel (∼2 events/s) to dictate the QDs from nonblinking to gradually blinking under increasing excitation. For high-quality CdSe/CdS core/shell QDs, Auger ionization of multiexciton for both charging and discharging is negligible.