Signal Considerations for Chronically Implanted Electrodes for Brain Interfacing

2007 ◽  
pp. 41-61 ◽  
Author(s):  
Warren Grill
Keyword(s):  
Implanted Electrodes

Brain shift: an error factor during implantation of deep brain stimulation electrodes

2007 ◽  
Vol 107 (5) ◽  
pp. 989-997 ◽  
Author(s):  
Yasushi Miyagi ◽  
Fumio Shima ◽  
Tomio Sasaki
Keyword(s):  
Deep Brain Stimulation ◽  
Brain Stimulation ◽  
Brain Shift ◽  
Mr Images ◽  
Implanted Electrodes ◽  
Error Factor ◽  
Bilateral Surgery ◽  
Second Procedure ◽  
The Brain ◽  
Deep Brain

Object The goal of this study was to focus on the tendency of brain shift during stereotactic neurosurgery and the shift's impact on the unilateral and bilateral implantation of electrodes for deep brain stimulation (DBS). Methods Eight unilateral and 10 bilateral DBS electrodes at 10 nuclei ventrales intermedii and 18 subthalamic nuclei were implanted in patients at Kaizuka Hospital with the aid of magnetic resonance (MR) imaging–guided and microelectrode-guided methods. Brain shift was assessed as changes in the 3D coordinates of the anterior and posterior commissures (AC and PC) with MR images before and immediately after the implantation surgery. The positions of the implanted electrodes, based on the midcommissural point and AC–PC line, were measured both on x-ray films (virtual position) during surgery and the postoperative MR images (actual position) obtained on the 7th day postoperatively. Results Contralateral and posterior shift of the AC and PC were the characteristics of unilateral and bilateral procedures, respectively. The authors suggest the following. 1) The first unilateral procedure elicits a unilateral air invasion, resulting in a contralateral brain shift. 2) During the second procedure in the bilateral surgery, the contralateral shift is reset to the midline and, at the same time, the anteroposterior support by the contralateral hemisphere against gravity is lost due to a bilateral air invasion, resulting in a significant posterior (caudal) shift. Conclusions To note the tendency of the brain to shift is very important for accurate implantation of a DBS electrode or high frequency thermocoagulation, as well as for the prediction of therapeutic and adverse effects of stereotactic surgery.

scholarly journals Probability-Based Prediction of Activity in Multiple Arm Muscles: Implications for Functional Electrical Stimulation

2008 ◽  
Vol 100 (1) ◽  
pp. 482-494 ◽  
Author(s):  
Chad V. Anderson ◽  
Andrew J. Fuglevand
Keyword(s):  
Electrical Stimulation ◽  
Functional Electrical Stimulation ◽  
Muscle Activity ◽  
Probability Distributions ◽  
Probabilistic Methods ◽  
Muscle Stimulation ◽  
Implanted Electrodes ◽  
Motor Behaviors ◽  
Wide Range ◽  
Arm Muscles

Functional electrical stimulation (FES) involves artificial activation of muscles with implanted electrodes to restore motor function in paralyzed individuals. The range of motor behaviors that can be generated by FES, however, is limited to a small set of preprogrammed movements such as hand grasp and release. A broader range of movements has not been implemented because of the substantial difficulty associated with identifying the patterns of muscle stimulation needed to elicit specified movements. To overcome this limitation in controlling FES systems, we used probabilistic methods to estimate the levels of muscle activity in the human arm during a wide range of free movements based on kinematic information of the upper limb. Conditional probability distributions were generated based on hand kinematics and associated surface electromyographic (EMG) signals from 12 arm muscles recorded during a training task involving random movements of the arm in one subject. These distributions were then used to predict in four other subjects the patterns of muscle activity associated with eight different movement tasks. On average, about 40% of the variance in the actual EMG signals could be accounted for in the predicted EMG signals. These results suggest that probabilistic methods ultimately might be used to predict the patterns of muscle stimulation needed to produce a wide array of desired movements in paralyzed individuals with FES.

Enhancement of Eye Motor Response and Electrical Brain Activity during Noise and Vibration in Rabbits

1982 ◽  
Vol 90 (1) ◽  
pp. 130-138 ◽  
Author(s):  
Ilmari Pyykkö ◽  
Izuru Matsuoka ◽  
Shinsuke Ito ◽  
Manabe Hinoki
Keyword(s):  
Motor Response ◽  
Optokinetic Nystagmus ◽  
Dorsal Hippocampus ◽  
Brain Activity ◽  
Noise And Vibration ◽  
Implanted Electrodes ◽  
Theta Waves ◽  
Electrical Brain Activity ◽  
The Relationship ◽  
Electroencephalogram Eeg

The relationship between electroencephalogram (EEG) and eye movements was studied in rabbits during optokinetic, vestibular, and optovestibular tests. EEG was recorded through permanently implanted electrodes. Exposure to noise and vibration increased the frequency and the velocity of optokinetic nystagmus (OKN). The increase was greater during vibration but greatest during combined noise and vibration. EEG activity was closely linked to changes in OKN and was particularly evident with the appearance of theta waves in the dorsal hippocampus. Also, rotation of the rabbit produced considerable activation in the EEG.

Facilitation of female reproductive behavior from mesensephalic central gray in the rat

1979 ◽  
Vol 237 (5) ◽  
pp. R278-R284 ◽  
Author(s):  
Y. Sakuma ◽  
D. W. Pfaff
Keyword(s):  
Electrical Stimulation ◽  
Mesencephalic Reticular Formation ◽  
Female Rats ◽  
Motor Systems ◽  
Functional Link ◽  
Implanted Electrodes ◽  
Unilateral Stimulation ◽  
Postural Changes ◽  
Central Gray ◽  
Stimulation Of

Electrical stimulation in the mesencephalic central gray (CG) and adjacent subtectum through chronically implanted electrodes in free-moving estrogen-primed ovariectomized female rats elicited a rapid and large facilitation of the lordosis reflex in response to either male mounts or manula cutaneous stimuli. Unilateral stimulation was sufficient for this effect. The facilitation increased in a graded manner to increased stimulus intensity, and was optimally evoked by stimuli delivered at 50--150 Hz. Facilitation disappeared rapidly following the end ot electrical stimulation, and within 15 min, reflex performance returned to the prestimulation level. Lordosis facilitation appeared when no aversive responses occurred; stimulation with comparable parameters at the lateral edge of CG or in the mesencephalic reticular formation often resulted in postural changes or aversive responses but was not able to facilitate lordosis. Lordosis refelx facilitation was probably mediated by projections descending from neurons in and around the CG, and represents stimulation of a functional link between ascending somatosensory and descending motor systems for the control of lordosis behavior.

Bursts and recurrences of bursts in the spike trains of spontaneously active striate cortex neurons

1985 ◽  
Vol 53 (4) ◽  
pp. 926-939 ◽  
Author(s):  
C. R. Legendy ◽  
M. Salcman
Keyword(s):  
Standard Deviation ◽  
Spike Train ◽  
Striate Cortex ◽  
Quantitative Measure ◽  
Spike Trains ◽  
Spike Rate ◽  
Occurrence Rate ◽  
Implanted Electrodes ◽  
Firing Rates ◽  
The Mean

Simultaneous recordings were made from small collections (2-7) of spontaneously active single units in the striate cortex of unanesthetized cats, by means of chronically implanted electrodes. The recorded spike trains were computer scanned for bursts of spikes, and the bursts were catalogued and studied. The firing rates of the neurons ranged from 0.16 to 32 spikes/s; the mean was 8.9 spikes/s, the standard deviation 7.0 spikes/s. Bursts of spikes were assigned a quantitative measure, termed Poisson surprise (S), defined as the negative logarithm of their probability in a random (Poisson) spike train. Only bursts having S greater than 10, corresponding to an occurrence rate of about 0.01 bursts/1,000 spikes in a random spike train, were considered to be of interest. Bursts having S greater than 10 occurred at a rate of about 5-15 bursts/1,000 spikes, or about 1-5 bursts/min. The rate slightly increased with spike rate; averaging about 2 bursts/min for neurons having 3 spikes/s and about 4.5 bursts/min for neurons having 30 spikes/s. About 21% of the recorded units emitted significantly fewer bursts than the rest (below 1 burst/1,000 spikes). The percentage of these neurons was independent of spike rate. The spike rate during bursts was found to be about 3-6 times the average spike rate; about the same for longer as for shorter bursts. Bursts typically contained 10-50 spikes and lasted 0.5-2.0 s. When the number of spikes in the successively emitted bursts was listed, it was found that in some neurons these numbers were not distributed at random but were clustered around one or more preferred values. In this sense, bursts occasionally "recurred" a few times in a few minutes. The finding suggests that neurons are highly reliable. When bursts of two or more simultaneously recorded neurons were compared, the bursts often appeared to be temporally close, especially between pairs of neurons recorded by the same electrode; but bursts seldom started and ended simultaneously on two channels. Recurring bursts emitted by one neuron were occasionally accompanied by time-locked recurring bursts by other neurons.

Long-term observations of spontaneous electrical activity of the uterine smooth muscle

1959 ◽  
Vol 196 (2) ◽  
pp. 343-350 ◽  
Author(s):  
C. Y. Kao
Keyword(s):  
Smooth Muscle ◽  
Electrical Activity ◽  
Action Potentials ◽  
Local Conditions ◽  
Pregnant Uterus ◽  
Implanted Electrodes ◽  
Spontaneous Electrical Activity ◽  
Myometrial Cells ◽  
Uterine Smooth Muscle

The spontaneous electrical activity of uterine smooth muscle was rather variable when acute observations were made. Therefore, a series of chronic experiments was performed with implanted electrodes to monitor a group of myometrial cells under different physiological conditions for periods up to eight weeks. The results showed that consistent behavior of myometrial cells could be observed provided similar hormonal status was maintained. Action potentials were rare or absent in myometrium of oophorectomized animals but were caused to appear by estrogen. In the pregnant uterus, action potentials increased both in amplitude and frequency of discharge as parturition approached, reached a peak at that time, and then declined in the postpartum days. The results indicated that in estrogen treatment and in parturition activities of myometrial cells were more synchronous. There was suggestive evidence that there were central impulses initiating activity in the pregnant uterus, and that the responses of the myometrium were affected by the local conditions.

Plasma 17-hydroxycorticosteroid levels during electrical stimulation of the amygdaloid complex in conscious monkeys

1958 ◽  
Vol 196 (1) ◽  
pp. 44-48 ◽  
Author(s):  
John W. Mason
Keyword(s):  
Electrical Stimulation ◽  
Large Dose ◽  
Rhesus Monkeys ◽  
Hypothalamic Stimulation ◽  
Amygdaloid Complex ◽  
Implanted Electrodes ◽  
Stimulation Of

Substantial plasma 17-OH-CS elevations invariably occurred during electrical stimulation of the amygdaloid complex in unanesthetized rhesus monkeys through chronically implanted electrodes. No evidence of localization of this effect within anatomical subdivisions of the amygdaloid complex was observed. Stimulation of the amygdala elicited plasma 17-OH-CS elevations (20 µg %/hr.) equal to those occurring with hypothalamic stimulation or injection of a large dose of ACTH (16 mg/kg), while no elevations were observed during putamen stimulation or under normal conditions.

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