Stimulus pulse-dependent responses in natural DNA biopolymer devices

2021 ◽  
Author(s):  
Yueh-Cheng Lin ◽  
Chi-Hsien Cheng ◽  
Yu-Chueh Hung
Keyword(s):  
Stimulus Pulse

Coding of directional information by single neurones in the S-segment of the FM bat, Myotis lucifugus

1980 ◽  
Vol 87 (1) ◽  
pp. 203-216
Author(s):  
P. H. Jen
Keyword(s):  
Single Unit ◽  
Median Plane ◽  
Myotis Lucifugus ◽  
Directional Information ◽  
Stimulus Pulse ◽  
Fm Bat ◽  
Single Neurones ◽  
The Relationship ◽  
Correct Level ◽  
Stimulus Direction

1. Response parameters of S-segment neurones of the FM bat Myotis lucifugus were measured as a sound was delivered from different azimuthal angles around the animal's head. 2. The response parameters investigated were the amplitude and threshold of the evoked potential (N3) of the S-segment, together with the threshold, latency and number of impulses (per stimulus pulse) of single units. 3. All the neurones studied had their lowest thresholds either at 20-40 degrees contralateral, or 20-40 degrees ipsilateral or at the front (0 degrees). 4. The amplitude of the sound affected the relationship between stimulus direction and the amplitude of a non-monotonic N3, and the relationship between stimulus direction and the number of impulses of a non-monotonic single unit. It had so such effects with a monotonic N3 and a monotonic single unit. 5. From a study of N3 amplitudes and numbers of impulses of single neurones, it appeared that an azimuthal difference as small as 3 degrees could be easily coded at a 95% correct level with stimuli presented at around 20 degrees ipsilateral, 20 degrees contralateral, and at the front. 6. The inter-aural pressure difference (IPD), which is considered an essential cue for echolocation in Myotis (Shimozawa et al. 1974), changed linearly with angle from 0 to 40 degrees lateral at a rate of 0.4 dB/degree for sounds between 33.5 and 49.0 kHz. 7. Assuming the just-detectable IPD to be 0.5 dB (as in man), the minimum detectable azimuthal difference of Myotis around the median plane would be 1.25 degrees.

scholarly journals Suprachoroidal electrical stimulation: effects of stimulus pulse parameters on visual cortical responses

2013 ◽  
Vol 10 (5) ◽  
pp. 056011 ◽  
Author(s):  
Sam E John ◽  
Mohit N Shivdasani ◽  
Chris E Williams ◽  
John W Morley ◽  
Robert K Shepherd ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Stimulus Pulse ◽  
Pulse Parameters ◽  
Cortical Responses ◽  
Visual Cortical

scholarly journals Responses of Cat Auditory Nerve Fibers to Biphasic Electrical Current Pulses

1987 ◽  
Vol 96 (1_suppl) ◽  
pp. 26-30 ◽  
Author(s):  
E. Javel ◽  
Y. C. Tong ◽  
R. K. Shepherd ◽  
G. M. Clark
Keyword(s):  
Auditory Nerve ◽  
Electrical Response ◽  
Nerve Fibers ◽  
Response Threshold ◽  
Stimulus Pulse ◽  
Current Pulses ◽  
Wide Range ◽  
Auditory Nerve Fibers ◽  
Ganglion Neurons ◽  
Electrical Stimuli

Discharge patterns of single auditory nerve fibers were recorded from normal-hearing cats implanted with a 12-band intracochlear electrode array. Stimuli were biphasic current pulses of specifiable width, amplitude, and rate. Acoustic tuning curves were obtained to determine the cochlear positions of the fibers. Response latencies to electrical stimuli formed two groups. Short latency (0.3 to 0.7 ms) responses were attributed to direct activation of spiral ganglion neurons. At high stimulus intensities, these often exhibited abrupt shifts toward even shorter latencies. Long latency (> 1.5 ms) responses were probably caused by electrophonic activation of functional hair cells. Response thresholds to electrical stimuli depended on a fiber's proximity to the stimulating electrodes, and they did not depend on a fiber's acoustic response threshold or spontaneous discharge rate. High intensity (> 1.5 mA) stimuli could excite fibers over a wide range of characteristic frequencies, even for the narrowest (0.45 mm) electrode separations. Response threshold was an exponentially decreasing function of pulse width for widths up to 300 μs/phase. Fiber discharges were highly phase-locked at all suprathreshold intensities, and saturation discharge rates usually equaled stimulus pulse rates for rates up to at least 800 pulses/s. Dynamic ranges were small (1 to 6 dB), increased with pulse rate, and were uncorrelated with electrical response threshold. Within the dynamic range, shapes of poststimulus time and interspike interval histograms resembled those obtained in response to acoustic stimuli. Depolarization block caused fiber activity to cease in 2 to 5 seconds for sustained stimuli presented at high (> 600 pulses/s) pulse rates and intensities.

scholarly journals Visualization of calcium transients controlling orientation of ciliary beat.

1994 ◽  
Vol 125 (5) ◽  
pp. 1127-1135 ◽  
Author(s):  
S L Tamm ◽  
M Terasaki
Keyword(s):  
Fluorescence Intensity ◽  
Sea Water ◽  
Entire Length ◽  
Mnemiopsis Leidyi ◽  
Ca Channels ◽  
Stimulus Pulse ◽  
Relative Extent ◽  
Voltage Dependent ◽  
Single Comb ◽  
Ciliary Beat

To image changes in intraciliary Ca controlling ciliary motility, we microinjected Ca Green dextran, a visible wavelength fluorescent Ca indicator, into eggs or two cell stages of the ctenophore Mnemiopsis leidyi. The embryos developed normally into free-swimming, approximately 0.5 mm cydippid larvae with cells and ciliary comb plates (approximately 100 microns long) loaded with the dye. Comb plates of larvae, like those of adult ctenophores, undergo spontaneous or electrically stimulated reversal of beat direction, triggered by Ca influx through voltage-sensitive Ca channels. Comb plates of larvae loaded with Ca Green dextran emit spontaneous or electrically stimulated fluorescent flashes along the entire length of their cilia, correlated with ciliary reversal. Fluorescence intensity peaks rapidly (34-50 ms), then slowly falls to resting level in approximately 1 s. Electrically stimulated Ca Green emissions often increase in steps to a maximum value near the end of the stimulus pulse train, and slowly decline in 1-2 s. In both spontaneous and electrically stimulated flashes, measurements at multiple sites along a single comb plate show that Ca Green fluorescence rises within 17 ms (1 video field) and to a similar relative extent above resting level from base to tip of the cilia. The decline of fluorescence intensity also begins simultaneously and proceeds at similar rates along the ciliary length. Ca-free sea water reversibly abolishes spontaneous and electrically stimulated Ca Green ciliary emissions as well as reversed beating. Calculations of Ca diffusion from the ciliary base show that Ca must enter the comb plate along the entire length of the ciliary membranes. The voltage-dependent Ca channels mediating changes in beat direction are therefore distributed over the length of the comb plate cilia. The observed rapid and virtually instantaneous Ca signal throughout the intraciliary space may be necessary for reprogramming the pattern of dynein activity responsible for reorientation of the ciliary beat cycle.

scholarly journals Effects of stimulus pulse rate on somatosensory adaptation in the human cortex

2021 ◽  
Author(s):  
Christopher L Hughes ◽  
Sharlene N Flesher ◽  
Robert A Gaunt
Keyword(s):  
Somatosensory Cortex ◽  
Neurological Diseases ◽  
Low Frequency ◽  
Stimulus Pulse ◽  
Continuous Stimulation ◽  
Intermittent Stimulation ◽  
Transient Activity ◽  
Human Participant ◽  
One Year ◽  
Over Time

AbstractBackgroundIntracortical microstimulation (ICMS) of the somatosensory cortex can restore sensation to people with neurological diseases. However, many aspects of ICMS are poorly understood, including the effect of continuous stimulation on percept intensity over time.ObjectiveHere, we evaluate how tactile percepts, evoked by ICMS in the somatosensory cortex of a human participant adapt over time.MethodsWe delivered continuous and intermittent ICMS to the somatosensory cortex and assessed the reported intensity of tactile percepts over time in a human participant. Experiments were conducted across approximately one year and linear mixed effects models were used to assess significance.ResultsContinuous stimulation at high frequencies led to rapid decreases in intensity, while low frequency stimulation maintained percept intensity for longer periods. Burst-modulated stimulation extended the time before the intensity began to decrease, but all protocols ultimately resulted in complete sensation loss within one minute. Intermittent stimulation paradigms with several seconds between stimulus trains also led to decreases in intensity on many electrodes, but never resulted in extinction of sensation after over three minutes of stimulation. Additionally, longer breaks between each pulse train resulted in some recovery of the stimulus-evoked percepts. For several electrodes, intermittent stimulation had almost no effect on the perceived intensity.ConclusionsIntermittent ICMS paradigms were more effective at maintaining percepts, and given that transient activity in the somatosensory cortex dominates the response to object contact, this stimulation method may mimic natural cortical activity and improve the perception of stimulation over time.

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