The Strength-Duration Curve

Evaluation of extraocular electrodes for a retinal prosthesis using evoked potentials in cat visual cortex

“…Increasing the stimulus pulse width lowered the current threshold for a response, to produce typical strengthduration relationships. 38 Also, the amplitude of the cortical evoked response saturated above certain current levels and did not show a linear increase (Fig. 5), which is more typical of a physiologic rather than an artefactual response.…”

“…The objectives of this study were to demonstrate that these electrodes can be easily implanted in a stable position on the sclera, and that they are effective in retinal stimulation at charge density levels that are safe for chronic neural stimulation. 37 Our aim was to obtain threshold, strength-duration, 38 and evoked response amplitude data for electrical stimulation of the retina with the ERP. This will allow optimization of stimulus parameters for an ERP and comparison of results with similar studies using intraocular electrodes.…”

Development of an extraocular retinal prosthesis: Evaluation of stimulation parameters in the cat

“…3). For anodal first stimulation, there was a decrease in the threshold current with increasing pulse duration, producing a typical strength-duration response 35 with a rheobase at Fig. 2.…”

Benzalkonium Chloride–Induced Denervation of Orbicularis Oculi Muscle in Rabbits

“…This curve can be parameterized by its rheobase (the current necessary to elicit a response with an infinite pulse width) and chronaxie (the pulse width necessary to elicit a response with a pulse magnitude of twice the rheobase). 19 While the rheobase value can be affected by factors such as the distance between the stimulating electrode and tissue being activated, the chronaxie value is a direct reflection of the membrane time constant, and therefore indicative of the tissue being activated. 20 We used electrical stimulation of eyelid movement to determine the innervation status of OOM muscles in rabbits who had been exposed to BAK and compared them with healthy controls.…”