Chronic intracochlear electrical stimulation at high charge densities results in platinum dissolution but not neural loss or functional changes in vivo

Electrical stimulation threshold and retinal ganglion cell density were measured in a rat model of retinal degeneration. We performed in vivo electrophysiology and morphometric analysis on normal and S334ter line 3 (RD) rats (ages 84–782 days). We stimulated the retina in anesthetized animals and recorded evoked responses in the superior colliculus. Current pulses were delivered with a platinum-iridium (Pt-Ir) electrode of 75-μm diameter positioned on the epiretinal surface. In the same animals used for electrophysiology, SMI-32 immunolabeling of the retina enabled ganglion cell counting. An increase in threshold currents positively correlated with age of RD rats. SMI-32-labeled retinal ganglion cell density negatively correlated with age of RD rats. ANOVA shows that RD postnatal day (P)100 and P300 rats have threshold and density similar to normal rats, but RD P500 and P700 rats have threshold and density statistically different from normal rats ( P < 0.05). Threshold charge densities were within the safety limits of Pt for all groups and pulse configurations, except at RD P600 and RD P700, where pulses were only safe up to 1- and 0.2-ms duration, respectively. Preservation of ganglion cells may enhance the efficiency and safety of electronic retinal implants.

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In Vivo Measurements of Cranial Electrical Stimulation Using Stereotactic-EEG: A Pilot Study

2021 10th International IEEE/EMBS Conference on Neural Engineering (NER) ◽

10.1109/ner49283.2021.9441106 ◽

2021 ◽

Author(s):

Minmin Wang ◽

Shenghua Zhu ◽

Haonan Guan ◽

Hongjie Jiang ◽

Jianmin Zhang ◽

...

Keyword(s):

Electrical Stimulation ◽

Pilot Study ◽

In Vivo Measurements

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Effects of Functional Electrical Stimulation Cycling of Different Duration on Viscoelastic and Electromyographic Properties of the Knee in Patients with Spinal Cord Injury

Brain Sciences ◽

10.3390/brainsci11010007 ◽

2020 ◽

Vol 11 (1) ◽

pp. 7

Author(s):

Antonino Casabona ◽

Maria Stella Valle ◽

Claudio Dominante ◽

Luca Laudani ◽

Maria Pia Onesta ◽

...

Keyword(s):

Spinal Cord ◽

Spinal Cord Injury ◽

Electrical Stimulation ◽

Functional Electrical Stimulation ◽

Muscle Activity ◽

Response Times ◽

Electromyographic Activity ◽

Functional Changes ◽

Pendulum Test ◽

Cord Injury

The benefits of functional electrical stimulation during cycling (FES-cycling) have been ascertained following spinal cord injury. The instrumented pendulum test was applied to chronic paraplegic patients to investigate the effects of FES-cycling of different duration (20-min vs. 40-min) on biomechanical and electromyographic characterization of knee mobility. Seven adults with post-traumatic paraplegia attended two FES-cycling sessions, a 20-min and a 40-min one, in a random order. Knee angular excursion, stiffness and viscosity were measured using the pendulum test before and after each session. Surface electromyographic activity was recorded from the rectus femoris (RF) and biceps femoris (BF) muscles. FES-cycling led to reduced excursion (p < 0.001) and increased stiffness (p = 0.005) of the knee, which was more evident after the 20-min than 40-min session. Noteworthy, biomechanical changes were associated with an increase of muscle activity and changes in latency of muscle activity only for 20-min, with anticipated response times for RF (p < 0.001) and delayed responses for BF (p = 0.033). These results indicate that significant functional changes in knee mobility can be achieved by FES-cycling for 20 min, as evaluated by the pendulum test in patients with chronic paraplegia. The observed muscle behaviour suggests modulatory effects of exercise on spinal network aimed to partially restore automatic neuronal processes.

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Somatostatin modulates cholinergic neurotransmission in canine antral muscle

AJP Gastrointestinal and Liver Physiology ◽

10.1152/ajpgi.1988.254.2.g201 ◽

1988 ◽

Vol 254 (2) ◽

pp. G201-G209 ◽

Cited By ~ 1

Author(s):

C. B. Koelbel ◽

G. van Deventer ◽

S. Khawaja ◽

M. Mogard ◽

J. H. Walsh ◽

...

Keyword(s):

Electrical Stimulation ◽

Substance P ◽

Prostaglandin E2 ◽

Positive Inotropic Effect ◽

Mechanical Response ◽

Inhibitory Effect ◽

Inotropic Effect ◽

Inotropic Response ◽

Cholinergic Neurotransmission

Somatostatin has been shown to inhibit antral motility in vivo. To examine the effect of somatostatin on cholinergic neurotransmission in the canine antrum, we studied the mechanical response of and the release of [3H]acetylcholine from canine longitudinal antral muscle in response to substance P, gastrin 17, and electrical stimulation. In unstimulated tissues, somatostatin had a positive inotropic effect on spontaneous phasic contractions. In tissues stimulated with substance P and gastrin 17, but not with electrical stimulation, somatostatin inhibited the phasic inotropic response dose dependently. This inhibitory effect was abolished by indomethacin. Somatostatin stimulated the release of prostaglandin E2 radioimmunoreactivity, and prostaglandin E2 inhibited the release of [3H]acetylcholine induced by substance P and electrical stimulation. Somatostatin increased the release of [3H]acetylcholine from unstimulated tissues by a tetrodotoxin-sensitive mechanism but inhibited the release induced by substance P and electrical stimulation. These results suggest that somatostatin has a dual modulatory effect on cholinergic neurotransmission in canine longitudinal antral muscle. This effect is excitatory in unstimulated tissues and inhibitory in stimulated tissues. The inhibitory effect is partially mediated by prostaglandins.

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Subthreshold electrical stimulation as a low power electrical treatment for stroke rehabilitation

Scientific Reports ◽

10.1038/s41598-021-93354-x ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Kyungsoo Kim ◽

Seung-Jun Yoo ◽

So Yeon Kim ◽

Taeju Lee ◽

Sung-Ho Lim ◽

...

Keyword(s):

Electrical Stimulation ◽

Energy Consumption ◽

Functional Recovery ◽

Stroke Rehabilitation ◽

Brain Regions ◽

Implantable Devices ◽

Rehabilitation Process ◽

Neural Excitability ◽

Spike Firing

AbstractAs a promising future treatment for stroke rehabilitation, researchers have developed direct brain stimulation to manipulate the neural excitability. However, there has been less interest in energy consumption and unexpected side effect caused by electrical stimulation to bring functional recovery for stroke rehabilitation. In this study, we propose an engineering approach with subthreshold electrical stimulation (STES) to bring functional recovery. Here, we show a low level of electrical stimulation boosted causal excitation in connected neurons and strengthened the synaptic weight in a simulation study. We found that STES with motor training enhanced functional recovery after stroke in vivo. STES was shown to induce neural reconstruction, indicated by higher neurite expression in the stimulated regions and correlated changes in behavioral performance and neural spike firing pattern during the rehabilitation process. This will reduce the energy consumption of implantable devices and the side effects caused by stimulating unwanted brain regions.

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