Human scalp EEG studies have shown that event-related desynchronization (ERD) in the alpha (8-13 Hz) and beta (15-25 bands may be used to detect functional activation of sensorimotor cortex. However, most previous somatotopy has not been examined detail brief, self-paced movements, focusing on planning motor output, used. We recorded electrocorticographic (ECoG) signals five clinical subjects during a visual-motor decision task was designed activate representations different body parts To...

We describe 6 patients who demonstrated postoperative neurological deficits despite unchanged somatosensory evoked potentials during intraoperative monitoring. Although there is both experimental and clinical evidence that are sensitive to some types of mishap, the technique should be employed with an awareness its possible limitations.

Summary: Stimulation of centromedian (CM) thalamic nuclei has been proposed as a treatment for seizures. We implanted programmable subcutaneous (s.c.) stimulators into CM bilaterally in 7 patients with intractable epilepsy to test feasibility and safety. was on or off 3‐month blocks, washout period double‐blind, cross‐over protocol. Stimuli were delivered 9O‐μs pulses at 65 pulses/s, 1 min each 5 2 h/day, voltage set half the sensory threshold. safe well‐tolerated, mean reduction...

We evaluated the current status of 131 patients with idiopathic parkinsonism who were receiving levodopa therapy. The residual parkinsonian symptoms and signs tabulated, as adverse effects from medication. Response to therapy was correlated duration disease treatment. Patients on-off or wearing-off likely have been treated for 4 years longer. 8 significantly more impaired than 0 3 years, even when matched total disease. These data suggest that deterioration responsiveness after several may...

<b><i>Objective:</i></b> To determine whether cortical electrical stimulation can terminate bursts of epileptiform activity in humans, we used afterdischarges (ADs) as a model activity. <b><i>Methods:</i></b> Cortical was performed for clinical localization purposes using subdural electrodes implanted patients undergoing preresection evaluations treatment medically intractable seizures. We 0.3-millisecond pulses alternating polarity, repeated at 50 pulses/second. When produced AD, often...

<b><i>Objective:</i></b> To investigate the functional-neuroanatomic substrates of word production using signed versus spoken language. <b><i>Methods:</i></b> The authors studied single-word processing with varying input and output modalities in a 38-year-old woman normal hearing speech who had become proficient sign language 8 years before developing intractable epilepsy. Subdural electrocorticography (ECoG) was performed during picture naming reading (visual inputs) repetition (auditory...

Little is known about what pathways subserve mirth and its expression laughter. We present three patients with gelastic seizures laughter elicited by electrical stimulation of the cortex who provide some insight into mechanisms emotional concomitants. The first patient had manifested without a subjective feeling mirth. Magnetic resonance imaging showed cavernous haemangioma in left superior mesial frontal region. Ictal subdural electrode recording seizure onset to be anterior cingulate...

With the use of a 3-dimensional finite element model human brain based on structural data from MRI scans, we simulated patterns current flow in cerebral hemisphere with different types electrical stimulation. Five tissue were incorporated into conductivities taken literature. The boundary value problem derived Laplace's equation was solved quasistatic approximation. Transcranial stimulation scalp electrodes poorly focussed and required high levels for cortex. Direct cortical bipolar...

Subdural electrocorticographic (ECoG) recordings in patients undergoing epilepsy surgery have shown that functional activation is associated with event-related broadband gamma activity a higher frequency range (>70 Hz) than previously studied human scalp EEG. To investigate the utility of this high (HGA) for mapping language cortex, we compared its neuroanatomical distribution maps derived from electrical cortical stimulation (ECS), which remains gold standard predicting impairment after...

F. A. Lenz, M. Rios, Zirh, D. Chau, G. Krauss, and R. P. Lesser. Painful stimuli evoke potentials recorded over the human anterior cingulate gyrus. J. Neurophysiol. 79: 2231–2234, 1998. Clinical studies of cingulotomy patients imaging predict that gyrus might display pain-related activity. We now report evoked by painful cutaneous stimulation with a CO 2 laser (LEP) from subdural electrodes medial wall hemisphere. In response to facial on both sides, negative (latency 211–242 ms) then...

The existence of the mu rhythm and its general anatomical physiological relationships are well known. There few data, however, regarding details specificity. We implanted fronto-temporal subdural electrode grids in 9 patients with intractable epilepsy to facilitate their surgical management. A 7–11 Hz cortical was observed 5–16 electrodes located over sensorimotor cortex as mapped by electrical stimulation. blocked contralateral face arm movements, passive movements arm, ipsilateral...

Safe parameters for electrical cortical stimulation in humans are difficult to estimate from the animal experimental literature. We therefore examined light microscopic histology at a total of 11 sites direct subdural stimulation, taken as part anterior temporal lobectomies 3 patients. Stimulations had been done through 3.175 mm diameter electrodes, with 0.3 msec square wave pulses alternating polarity 50 pulses/sec. In 2 patients, one site each used common reference receiving over 251...

Somatosensory evoked potentials were recorded from chronically implanted subdural electrodes in six patients with intractable seizures. The following conclusions reached: 1) initial cortical negativity-positivity (N1 a latency of about 20 msec and P2 24 msec) the postcentral area was an expression classical primary surface positivity, but N1 generated by posterior pole early horizontal dipole 3b, positive slightly delayed vertical 1 2.2) permitted most accurate localization somatosensory...

We studied 37 patients who had head and eye turning during 74 spontaneous epileptic seizures. Videotapes EEGs were analyzed independently. Turning movements classified without knowledge of EEG or clinical data as either versive (unquestionably forced involuntary, resulting in sustained unnatural positioning) nonversive (mild, unsustained, wandering, seemingly voluntary). Videotape observations then correlated with the location seizure onset. Contralateral occurred 61 seizures 27 patients,...

This is the first epilepsy surgery series to analyze definition of "completeness" resection, based solely on results chronic scalp and subdural EEG recording. When patients had complete removal all cortical areas with ictal interictal epileptiform discharges, clinical outcome was usually good. discharges were left behind, good significantly less frequent. correlation between resection independent presence or absence CT-detected structural lesions sharp waves post-resection...

Summary: Intraoperative cortical stimulation for evaluation of function has been used extensively to define the extent excisions surgical treatment epilepsy. With chronic implantation subdural electrodes, extraoperative becomes possible, and these favorable testing conditions permit more precise mapping cortex. This assists surgeon in planning details removal also provides additional data about human Four aspects which detailed studies have provided information complementing pioneer...

Abstract Alterations in a variety of neurotransmitter systems have been identified experimental models epilepsy and brain tissue from patients with intractable temporal lobe seizures. The availability new high‐affinity radioligands permits the study some neuroreceptors vivo positron emission tomography (PET). We previously characterized binding 11 C‐carfentanil, potent selective mu opiate receptor agonist, described increases C‐carfentanil neocortex unilateral epilepsy. These studies...

Summary: We have evaluated the afterdischarge thresholds and functional response in 21 patients with chronically implanted arrays of subdural electrodes. Afterdischarge varied from 2 to &gt; 15 mA over tested cortex, by as much 12 individual patients, between adjacent Thresholds for alteration 9.5 individually 6.5 conclude that optimal localization cortical areas requires different stimulation intensities at points. The use too high an intensity would produce afterdischarges some positions....

With the aid of chronic subdural electrodes we have been able to record from posterior banks sylvian fissure, auditory evoked potentials (AEPs) that had morphologies and peak latencies compatible with primary AEPs described by Celesia Puletti (1969). These amplitudes were not only affected side stimulus presentation but maximal in an area close cortex. The also displayed extremely steep spatial gradient altered pentobarbitone sodium nitrous oxide anaesthesia. Together, these properties...

1. Somatosensory evoked potentials to median nerve stimulation recorded from neck-scalp derivation consisted of four components: two negativities (N10 and N12) which were the neck electrode positivities (P11 P13) scalp electrode. 2. Evidence is presented pointing following origin these N10 = afferent volley at peripheral immediately before it enters intervertebral foramen; P11 dorsal rootlets C6; N12 postsynaptic cord (ipsilateral horns C6, C7); P13 in column level foramen magnum. 3. In main...