Search results for "Electrodes"
showing 10 items of 231 documents
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…
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…
Reward Unpredictability inside and outside of a Task Context as a Determinant of the Responses of Tonically Active Neurons in the Monkey Striatum
2001
Tonically active neurons (TANs) in the monkey striatum are involved in detecting motivationally relevant stimuli. We recently provided evidence that the timing of conditioned stimuli strongly influences the responsiveness of TANs, the source of which is likely to be the monkey's previous experience with particular temporal regularities in sequential task events. To extend these findings, we investigated the relationship of TAN responses to a primary liquid reward, the timing of which is more or less predictable to the monkey either outside of a task or during instrumental task performance. Reward predictability was indexed by the timing characteristics of the mouth movements. The responsive…
Hippocampal theta-band activity and trace eyeblink conditioning in rabbits.
2009
The authors examined the relationship between hippocampal theta activity and trace eyeblink conditioning. Hippocampal electrophysiological local field potentials were recorded before, during, and after conditioning or explicitly unpaired training sessions in adult male New Zealand White rabbits. As expected, a high relative power of theta activity (theta ratio) in the hippocampus predicted faster acquisition of the conditioned response during trace conditioning but, contrary to previous results obtained using the delay paradigm, only in the initial stage of learning. The presentation of the conditioned stimulus overall elicited an increase in the hippocampal theta ratio. The theta ratio dec…
Natural history of the Sprint Fidelis lead: survival analysis from a large single-center study.
2012
The purposes of our study were to: (1) determine lead failure rate in a large single-center cohort of Sprint Fidelis 6949 (Fidelis) leads, (2) define the risk of lead failure over time, (3) assess the impact of the Lead Integrity Alert (LIA) on lead failure presentation, and (4) identify independent predictors of Fidelis lead failure. All patients who underwent implantation of a Fidelis lead between September 2004 and July 2007 were included. Demographic, clinical, and device characteristics at the time of implant and prior to failure were collected and analyzed. A total of 971 Fidelis leads (706 men, 265 women, mean age 68.4 ± 12.8 years) were implanted. Over a mean follow-up of 46.3 month…
Is atrial sensing of ventricular far-field signals important in single-lead VDD pacing?
1998
UNLABELLED In single-lead VDD pacing the atrial sensitivity frequently is programmed to sensitive values. Atrial sensing of ventricular far-field signals should be reduced by differential atrial sensing. The aim of the study was to evaluate the effectiveness of this approach. METHODS The study included 10 patients with a single-lead VDD pacemaker (Thera 8948, Lead 5032). The atrial sensitivity was set to its most sensitive value of 0.18 mV and the telemetered intraatrial EGM was continuously recorded. After atrial tracked ventricular pacing, VVI pacing was performed with pacing rates from 100 to 160 beats/min in steps of 10 beats/min and up to 165 beats/min. The peak-to-peak amplitudes of P…