Search results for "Implanted"

Different neuronal contribution to N20 somatosensory evoked potential and to CO2 laser evoked potentials: an intracerebral recording study

2004

Abstract Objective : To investigate the possible contribution of the primary somatosensory area (SI) to pain sensation. Methods : Depth recordings of CO 2 laser evoked potentials (LEPs) and somatosensory evoked potentials (SEPs) were performed in an epileptic patient with a stereotactically implanted electrode (Talairach coordinates y =−23, z =40) that passed about 10 mm below the hand representation in her left SI area, as assessed by the source of the N20 SEP component. Results : The intracerebral electrode was able to record the N20 SEP component after non-painful electrical stimulation of her right median nerve. The N20 potential showed a phase reversal in the bipolar montage (at about …

Relationship between the caudate nucleus and the dorsal hippocampus, in the cat.

1972

Asymmetries in classically conditioned head movements and cingulate cortex slow potentials in cats.

1991

Presuming that conditioned head movements in the cat indicate a preference for a specific direction, asymmetries were also expected to be found in bilaterally recorded cingulate cortex slow potentials to a symmetrical tone stimulus during discriminative conditioning. Conditioned stimuli (CS, 1000 and 2500 Hz tones) were delivered through two miniature loudspeakers fitted to the head in front of both ears. The unconditioned stimulus (US) was an electrical stimulation of either the left or right lateral hypothalamus yielding, in addition to its rewarding effects, an unconditioned head turning response (UR) either to the left, right, forwards or upwards. Discrimination learning appeared as mor…

Induced Dipoles and Possible Modulation of Wireless Effects in Implanted Electrodes. Effects of Implanting Insulated Electrodes on an Animal Test to …

2021

There is evidence that Deep Brain Stimulation (DBS) produces health benefits in patients even before initiating stimulation. Furthermore, DBS electrode insertion in rat infralimbic cortex (ILC) provokes antidepressant-like effects before stimulation, due to local inflammation and astrogliosis. Consequently, a significant effect of implanting electrodes is suspected. External fields, similar in magnitude to the brain’s endogenous fields, induce electric dipoles in conducting materials, in turn influencing neural cell growth through wireless effects. To elucidate if such dipoles influence depressive-like behavior, without external stimulation, the comparative effect of conducting and insulate…

EEG and MEG primers for tracking DBS network effects

2020

Deep brain stimulation (DBS) is an effective treatment method for a range of neurological and psychiatric disorders. It involves implantation of stimulating electrodes in a precisely guided fashion into subcortical structures and, at a later stage, chronic stimulation of these structures with an implantable pulse generator. While the DBS surgery makes it possible to both record brain activity and stimulate parts of the brain that are difficult to reach with non-invasive techniques, electroencephalography (EEG) and magnetoencephalography (MEG) provide complementary information from other brain areas, which can be used to characterize brain networks targeted through DBS. This requires, howeve…

Intracranial measurement of current densities induced by transcranial magnetic stimulation in the human brain

2003

Transcranial magnetic stimulation (TMS) is a non-invasive technique that uses the principle of electromagnetic induction to generate currents in the brain via pulsed magnetic fields. The magnitude of such induced currents is unknown. In this study we measured the TMS induced current densities in a patient with implanted depth electrodes for epilepsy monitoring. A maximum current density of 12 microA/cm2 was recorded at a depth of 1 cm from scalp surface with the optimum stimulation orientation used in the experiment and an intensity of 7% of the maximal stimulator output. During TMS we recorded relative current variations under different stimulating coil orientations and at different points…

Pacemaker therapy in premature children with high degree AV block.

1998

The smallest pacemaker pulse generator and a steroid-eluting bipolar epicardial lead were implanted in two premature children with symptomatic AV block. Stable capture threshold and high amplitude evoked response electrogram resulted in normal function of the pacemaker Autocapture algorithm, which adjusts output 0.3 V above the measured capture threshold. Autocapture had previously been used only with endocardial leads. Longer-term observation is required.

Scalp, basal epidural and intravascular far-field recordings after median nerve stimulation: evidence for a separate N18a potential

2000

Far-field somatosensory evoked potentials (SSEPs) after median nerve stimulation were recorded from scalp- (Fz), epidural- (ED) and intravascular electrodes (basilar artery [Bas]) to study the nature of the controversial N18a component of the widespread N18 potential. In healthy volunteers frequently an N18a potential was recorded at Fz. Simultaneous Fz and ED recordings at the pontomesencephalic junction as well as Bas-recordings at the caudal basilar artery showed N18a components identical in latency and shape. With intravascular recordings the shapes differed between the top of the basilar artery and the caudal artery recordings. These findings support the existence of a separate N18a po…

Laparoscopic endopelvic sacral implantation of a Brindley controller for recovery of bladder function in a paralyzed patient

2008

Background: A number of techniques are being investigated to accomplish bladder control recovery in paralyzed patients using the neurostimulation, but currently, all techniques are based on the dorsal implantation of the electrodes using a laminectomy. Methods: On 27 April 2006 we performed a laparoscopic implantation of a Finetech-Brindley bladder controller on the endopelvic sacral roots in a Th8 completely paralyzed woman who had previously undergone the removal of a Brindley controller due to an arachnoiditis after extrathecal implantation with intradural sacral deafferentation. Results: We required about 3.5 h for the entire surgical procedure; no complications occurred and the patient…

European Clinical Experience with a Dual Chamber Single Pass Sensing and Pacing Defibrillation Lead

2002

Dual chamber ICDs are increasingly implanted nowadays, mainly to improve discrimination between supraventricular and ventricular arrhythmias but also to maintain AV synchrony in patients with bradycardia. The aim of this study was to investigate a new single pass right ventricular defibrillation lead capable of true bipolar sensing and pacing in the right atrium and integrated bipolar sensing and pacing in the right ventricle. The performance of the lead was evaluated in 57 patients (age 61 +/- 12 years; New York Heart Association 1.9 +/- 0.6, left ventricular ejection fraction 0.38 +/- 0.15) at implant, at prehospital discharge, and during a 1-year follow-up. Sensing and pacing behavior of…