Search results for "Electrode"
showing 10 items of 950 documents
Nucleus incertus contribution to hippocampal theta rhythm generation.
2006
The hippocampal theta rhythm is generated by the pacemaker activity of the medial septum-diagonal band of Broca (MS/DBB) neurons. These nuclei are influenced by brainstem structures that modulate the theta rhythm. The aim of the present work is to determine whether the nucleus incertus (NI), which has important anatomical connections with the MS/DBB, contributes to the hippocampal theta rhythm generation in rats. Hippocampal field activity was recorded in urethane-anaesthetized rats. Electrical stimulation of the NI not only evoked theta rhythm in the hippocampus, but also decreased the amplitude of delta waves. Unit recordings in the NI revealed either a non-rhythm discharge pattern in mos…
Incidental finding of migrated pacing lead fragment into pulmonary artery detected with CT
2013
This case shows a rare complication of a migrated atrial lead into the pulmonary artery incidentally detected during a comprehensive evaluation of coronary CT angiography.
A repetitive intracortical microstimulation pattern induces long-lasting synaptic depression in brain slices of the rat primary somatosensory cortex.
2000
Repetitive intracortical microstimulation (ICMS) applied to the rat primary somatosensory cortex (SI) in vivo was reported to induce reorganization of receptive fields and cortical maps. The present study was designed to exam- ine the effect of such an ICMS pattern applied to layer IV of brain slices containing SI on the efficacy of synaptic in- put to layer II/III. Effects of ICMS on the synaptic strength was quantified for the first synaptic component ( s1) of cor- tical field potentials (FPs) recorded from layer II/III of SI. FPs were evoked by stimulation in layer IV. The pattern of ICMS was identical to that used in vivo. However, stimula- tion intensity had to be raised to induce an a…
Nitric oxide-active compounds modulate the intensity of glutamate-evoked responses in the globus pallidus of the rat
2011
Abstract Aim The effects of local applied NO-active compounds on glutamate (GLU)-evoked responses were investigated in globus pallidus (GP) neurons. Main methods Extracellularly recorded single units from anesthetized rats were treated with GLU before and during the microiontophoretic application of S-nitrosoglutathione (SNOG), a NO donor, and Nω-nitro- l -arginine methyl ester (L-NAME), a NOS inhibitor. Key findings Most GP cells were excited by SNOG whereas administration of L-NAME induced decrease of GP neurons activity. Nearly all neurons responding to SNOG and/or L-NAME showed significant modulation of their excitatory responses to the administration of iontophoretic GLU. In these cell…
Laminar and Columnar Structure of Sensory-Evoked Multineuronal Spike Sequences in Adult Rat Barrel Cortex In Vivo
2014
One of the most relevant questions regarding the function of the nervous system is how sensory information is represented in populations of cortical neurons. Despite its importance, the manner in which sensory-evoked activity propagates across neocortical layers and columns has yet not been fully characterized. In this study, we took advantage of the distinct organization of the rodent barrel cortex and recorded with multielectrode arrays simultaneously from up to 74 neurons localized in several functionally identified layers and columns of anesthetized adult Wistar rats in vivo. The flow of activity within neuronal populations was characterized by temporally precise spike sequences, which …
Morphological and electrophysiological evidence for habenular influence on the guinea-pig pineal gland
1981
The central innervation of the guinea-pig pineal gland was investigated by histological and electrophysiological methods: Staining the pineal gland and the epithalamus, a double route of central innervation could be shown in the anterior part of the organ: (a) Fibres from the habenular nuclei, mainly from the lateral part, penetrate the organ via the pineal stalk. (b) Other fibres join the striae medullares and running in the habenulae reach the organ more dorsally. The fibres end in the intercellular space where they form a dense network. In 15 male guinea-pigs under urethane anesthesia, two series of unit recording experiments were performed: (a) Recordings were made from 128 units in the…
Modulatory role of acetylcholine in the rat pineal gland
1998
Abstract The function of acetylcholine (ACh) in the mammalian pineal gland is unknown. To test the hypothesis that ACh exerts a modulatory role in this organ, in the present study electrophysiogical multiunit recordings were carried out in ex-vivo rat pineal glands superfused with different drugs. It was found that ACh (10 −7 M) as well as the cholinergic agonists oxotremorine (10 −7 M) and nicotine (10 −6 M) increased the discharge rates of most of the spontaneously active units and led to burst activity in previously regularly firing cells. It is concluded that ACh may play a modulatory role in the pineal by influencing the firing of a special population of pineal cells with perhaps recep…
Mechanisms underlying hyperpolarization evoked by P2Y receptor activation in mouse distal colon
2006
In murine colonic circular muscle, ATP mediates fast component of the nerve-evoked inhibitory junction potentials, via activation of P2Y receptors and opening of apamin-sensitive Ca2+-dependent K+ channels. We investigated, using microelectrode recordings, the intracellular events following P2Y-receptor activation by electrical field stimulation or by adenosine 5'-O-2-thiodiphosphate (ADPbetaS), ATP stable analogue. The fast-inhibitory junction potential amplitude was reduced by thapsigargin or ciclopiazonic acid (CPA), sarcoplasmic reticulum Ca2+-ATPase inhibitors, by ryanodine, which inhibits Ca2+ release from ryanodine-sensitive stores, and by 9-(tetrahydro-2-furanyl)-9H-purin-6-amine (S…
Gastric control of duodenal electric activity--the function of the gastroduodenal junction.
1975
An investigation was made into the links between electric activity of antral and of duodeno-jejunal musculature in different functional conditions. The function of the gastroduodenal junction in this linking mechanism was analysed. The following observations were made: (a) in the absence of gastric stimulation, the slow electric activities of stomach and duodenum appear to be completely independent; (b) the gastroduodenal junction evidences no electric activity of its own but is affected by that of the two adjacent structures; (c) chemical stimulation of the gastric mucosa causes activation of the electric and mechanical activity of the stomach and analogous activation of duodenal musculatu…
A Strange Case of Downward Displacement of a Deep Brain Stimulation Electrode 10 Years Following Implantation: The Gliding Movement of Snakes Theory.
2014
Background Despite the best efforts to ensure stereotactic precision, deep brain stimulation (DBS) electrodes can wander from their intended position after implantation. We report a case of downward electrode migration 10 years following successful implantation in a patient with Parkinson disease. Methods A 53-year-old man with Parkinson disease underwent bilateral implantation of DBS electrodes connected to a subclavicular 2-channel pulse generator. The generator was replaced 7 years later, and a computed tomography (CT) scan confirmed the correct position of both leads. The patient developed a gradual worsening affecting his right side 3 years later, 10 years after the original implantati…