Subdural recordings from an awake human brain for measuring current intensity during transcranial direct current stimulation.

Transcranial direct current stimulation (tDCS) is an emerging method, used for non-invasively stimulating the brain in normal healthy subjects and in patients with neurological disorders. However, the pattern of the spatial distribution of the current intensity induced by tDCS is poorly understood. In this study, we directly measured the spatial characteristics of the current intensity induced by tDCS using an intracranial strip electrode array implanted over the motor cortex in patients with Parkinson's disease undergoing deep brain stimulation lead placement surgery.

Characterization of Subdural Stimulation-Induced Afterdischarge Activity Using the Continuous Wavelet Transform.

Objective: We address the problem of characterization of afterdischarges (ADs) that often arise in patients with intractable focal epilepsy who, as part of their evaluation, undergo cortical electrical stimulation: A standard diagnostic and evaluation procedure before respective surgery.

Results: A total of 1333 channels of data recorded in 17 trials of seven patients whose EEG showed ADs (on a total of 156 channels) during cortical stimulation were examined in the time-scale domain using a complex Morlet scalogram. We found excellent characterization of the AD channels based on the distribution functions of the sum of the wavelet coefficients in the two lowest scales corresponding to the frequency range [20, 80] Hz, i.

An asymmetric solar wind termination shock.

Voyager 2 crossed the solar wind termination shock at 83.7 au in the southern hemisphere, approximately 10 au closer to the Sun than found by Voyager 1 in the north. This asymmetry could indicate an asymmetric pressure from an interstellar magnetic field, from transient-induced shock motion, or from the solar wind dynamic pressure.

Termination of epileptiform activity by cooling in rat hippocampal slice epilepsy models.

Cooling has been shown to terminate experimentally induced epileptiform activity in models of epilepsy without causing injury to the cooled brain, suggesting that cooling could represent an approach to seizure control in intractable focal epilepsies. Here we sought to determine the most effective way to apply cooling to abort spontaneous epileptiform discharges in in vitro brain slice models. We induced spontaneous epileptiform activity in rat brain slices by exposure to 4-aminopyridine (4-AP), 4-AP plus bicuculline, and Mg(2+)-free artificial CSF (aCSF) at 28-34 degrees C.

Enhancements of energetic particles near the heliospheric termination shock.

The spacecraft Voyager 1 is at a distance greater than 85 au from the Sun, in the vicinity of the termination shock that marks the abrupt slowing of the supersonic solar wind and the beginning of the extended and unexplored distant heliosphere. This shock is expected to accelerate 'anomalous cosmic rays', as well as to re-accelerate Galactic cosmic rays and low-energy particles from the inner Solar System. Here we report a significant increase in the numbers of energetic ions and electrons that persisted for seven months beginning in mid-2002.

Optimizing parameters for terminating cortical afterdischarges with pulse stimulation.

Purpose: We previously reported that brief pulses of electrical stimulation (BPSs) can terminate afterdischarges (ADs) during cortical stimulation. We investigated conditions under which BPS is more likely to suppress ADs.

Methods: We analyzed parameters altering BPS effectiveness on 200 ADs in seven patients with implanted subdural electrodes.