Threshold movements produced by excitation of cerebral cortex and efferent fibers with some parametric regions of rectangular current pulses (cats and monkeys)

Lilly, John C.; Austin, Garth E.; Chambers, W. W.

doi:10.1152/jn.1952.15.4.319

Cited by 80 publications

(33 citation statements)

References 23 publications

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“…In general, these relationships between liminal I and pulse frequency are similar to those found in the motor cortex by Mihailovic and Delgado (33) and Lilly et al (31), except that a relatively shallower slope in the low-frequency range was reported by the latter group.…”

Section: Pulse Frequencysupporting

confidence: 88%

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Production of Threshold Levels of Conscious Sensation by Electrical Stimulation of Human Somatosensory Cortex

Libet¹,

Alberts²,

Wright³

et al. 1993

Neurophysiology of Consciousness

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unf~ and bipolar electrode arrangement, and electrode size or area. Since the parameters are interrelated in their effectiveness, one can draw from this study differing parametric points 4 for adequate stimuli that may be suitable for different experimental purposes; perhaps even more importantly, one finds that certain parametric regions may not be suitable at all for certain purposes. In addition, the influence of some aspects of the alerting procedures, and their correlated statesbf EEG-alpha rhythm, on cerebral and peripheral sensory thresholds was analyzed. METHODSSubjects and general procedure. The subjects for this study were selected from among cooperative patients who were to undergo neurosurgical treatment for dyskinesias, mainly parkinsonism. Pneumoencephalography and trephination is carried out in a first stage under general anesthesia; the actual therapy is carried out at another time with the patient unanesthetized (13, 26) in order to permit appropriate activation and inactivation tests to be conducted on the responses of the target tissues (2). It was during these second stage operations that the present studies were carried out. The use of the Leksell stereotaxic instrument permits flexibility in choosing the cortical site of entry of the therapy electrode. A surprisingly high percentage of the patients was able to tolerate well the 30-to 90-min. period of cortical testing. A study period was terminated when the patient demonstrated reluctance or an unreliability of responses which often appeared in association with fatigue. The total number of such study sessions in the operating room which were successful in part or whole in contributing to this study was 99, carried out on 92 patients. Since each testing period could ordinarily contribute data significant to only one or a few of the points under investigation, the total number of subjects involved in attempting to establish individual relationships is in some instances not as large as one would like.The general procedure during those second-stage operations which were used for investigative purposes was as follows. With the stereotaxic instrument in place and the available area of cerebral cortex exposed, the primary somatosensory area on the flat region of the postcentral gyrus was localized with an exploring stimulating electrode (usually with 0.5-msec. square pulses, alternating in polarity (1), 60 pulses/sec. trains of less than 1 sec. duration). Assurance that the area under investigation was in fact the postcentral gyrus was obtained in almost all cases by eliciting typical pyramidal-type motor responses (3) from the cortical gyrus just anterior to the sulcus bordering the gyrus in question. The cortical area of representation of sensation usually involved some portion of the contralateral hand or, less commonly, of the wrist or forearm. The appropriate stimulating electrode was then placed on that cortical point requiring the minimum current for eliciting this conscious sensory response. There was no particular locus on the postcentral ...

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Section: Pulse Frequencysupporting

confidence: 88%

“…In order to eliminate electrode polarization, electrodes similar to those utilized by Lilly et al (31) to stimulate motor cortex were used routinely, unless otherwise specified. These are Ag-AgCI electrodes with a large chlorided-metal surface area (ca.…”

Section: Methodsmentioning

confidence: 99%

Production of Threshold Levels of Conscious Sensation by Electrical Stimulation of Human Somatosensory Cortex

Libet¹,

Alberts²,

Wright³

et al. 1993

Neurophysiology of Consciousness

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“…Supporting the concept that damage is due to electrochemical reaction products is the work by Lilly et al (1952), which demonstrated that loss of electrical excitability and tissue damage occurs when the cerebral cortex of monkey is stimulated using monophasic current pulses. Later, Lilly et al (1955) showed that biphasic stimulation caused no loss of excitability or tissue damage after 15 weeks of stimulation for 4-5 h per day.…”

Section: Mechanisms Of Damagementioning

confidence: 99%

Electrical stimulation of excitable tissue: design of efficacious and safe protocols

Merrill

Bikson

Jefferys

2005

Journal of Neuroscience Methods

1,791

1,639

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“…Many researchers have indicated from their studies that neuronal damage is electrochemically induced [8-10]. McCreery et al attempted to differentiate between electrochemically induced and neuronal activity induced injury by using platinum (faradaic) and tantalum pentaoxide (capacitor) electrodes [11].…”

Section: Introductionmentioning

confidence: 99%

Neural electrode degradation from continuous electrical stimulation: Comparison of sputtered and activated iridium oxide

Negi

Bhandari

Rieth

et al. 2010

Journal of Neuroscience Methods

118

113

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The performance of neural electrodes in physiological fluid, especially in chronic use, is critical for the success of functional electrical stimulation devices. Tips of the Utah Electrode Arrays (UEA) were coated with sputtered iridium oxide film (SIROF) and activated iridium oxide film (AIROF) to study the degradation during charge injection consistent with functional electrical stimulation (FES). The arrays were subjected to continuous biphasic, cathodal first, charge balanced (with equal cathodal and anodal pulse widths) current pulses for 7 hours (> 1 million pulses) at a frequency of 50 Hz. The amplitude and width of the current pulses were varied to determine the damage threshold of the coatings. Degradation was characterized by scanning electron microscopy, inductively coupled plasma mass spectrometry, electrochemical impedance spectroscopy and cyclic voltammetry. The injected charge and charge density per phase were found to play synergistic role in damaging the electrodes. The damage threshold for SIROF coated electrode tips of the UEA was between 60 nC with a charge density of 1.9 mC/cm2 per phase and 80 nC with a charge density of 1.0 mC/cm2 per phase. While for AIROF coated electrode tips, the threshold was between 40 nC with a charge density of 0.9 mC/cm2 per phase, and 50 nC with a charge density of 0.5 mC/cm2 per phase. Compared to AIROF, SIROF showed higher damage threshold and therefore is highly recommended to be used as a stimulation material.

show abstract

Threshold movements produced by excitation of cerebral cortex and efferent fibers with some parametric regions of rectangular current pulses (cats and monkeys)

Cited by 80 publications

References 23 publications

Production of Threshold Levels of Conscious Sensation by Electrical Stimulation of Human Somatosensory Cortex

Production of Threshold Levels of Conscious Sensation by Electrical Stimulation of Human Somatosensory Cortex

Electrical stimulation of excitable tissue: design of efficacious and safe protocols

Neural electrode degradation from continuous electrical stimulation: Comparison of sputtered and activated iridium oxide

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