Thresholds for activation of rabbit retinal ganglion cells with an ultrafine, extracellular microelectrode.

نویسندگان

  • Ralph J Jensen
  • Joseph F Rizzo
  • Ofer R Ziv
  • Andrew Grumet
  • John Wyatt
چکیده

PURPOSE To determine electrical thresholds required for extracellular activation of retinal ganglion cells as part of a project to develop an epiretinal prosthesis. METHODS Retinal ganglion cells were recorded extracellularly in retinas isolated from adult New Zealand White rabbits. Electrical current pulses of 100- micro s duration were delivered to the inner surface of the retina from a 5- micro m long electrode. In about half of the cells, the point of lowest threshold was found by searching with anodal current pulses; in the other cells, cathodal current pulses were used. RESULTS Threshold measurements were obtained near the cell bodies of 20 ganglion cells and near the axons of 19 ganglion cells. Both cathodal and anodal stimuli evoked a neural response in the ganglion cells that consisted of a single action potential of near-constant latency that persisted when retinal synaptic transmission was blocked with cadmium chloride. For cell bodies, but not axons, thresholds for both cathodal and anodal stimulation were dependent on the search method used to find the point of lowest threshold. With search and stimulation of matching polarity, cathodal stimuli evoked a ganglion cell response at lower currents (approximately one seventh to one tenth axonal threshold) than did anodal stimuli for both cell bodies and axons. With cathodal search and stimulation, cell body median thresholds were somewhat lower (approximately one half) than the axonal median thresholds. With anodal search and stimulation, cell body median thresholds were approximately the same as axonal median thresholds. CONCLUSIONS The results suggest that cathodal stimulation should produce lower thresholds, more localized stimulation, and somewhat better selectivity for cell bodies over axons than would anodal stimulation.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Chloride channel protein 2 prevents glutamate-induced apoptosis in retinal ganglion cells

Objective(s): The purpose of this study was to investigate the role of chloride channel protein 2 (ClC-2) in glutamate-induced apoptosis in the retinal ganglion cell line (RGC-5). Materials and Methods: RGC-5 cells were treated with 1 mM glutamate for 24 hr. The expression of ClC-2, Bax, and Bcl-2 was detected by western blot analysis. Cell survival and apoptosis were measured by 3-(4,5-dimeth...

متن کامل

Stem ‍Cells in Glaucoma Management

Glaucoma is the leading cause of preventable blindness worldwide. Despite tremendous advances in medical and surgical management of glaucoma in the recent years, the prevalence of glaucoma related blindness is anticipated to increase in the future decades because of the aging population. Stem cells have the potential to change the glaucoma management in several ways. There are several areas of ...

متن کامل

Direct activation and temporal response properties of rabbit retinal ganglion cells following subretinal stimulation.

In the last decade several groups have been developing vision prostheses to restore visual perception to the profoundly blind. Despite some promising results from human trials, further understanding of the neural mechanisms involved is crucial for improving the efficacy of these devices. One of the techniques involves placing stimulating electrodes in the subretinal space between the photorecep...

متن کامل

Epithelial sodium channels (ENaC) produce extracellular positive DC potentials in the retinal neuroepithelium.

Positive DC (direct current) potentials were measured in the extracellular space in the retinal neuroepithelium of chick embryos. The positive DC potential was suppressed by amiloride, a blocker for epithelial Na(+) channels (ENaC). Amiloride also decreased the resistance of the extracellular space as measured by passing a constant current through a microelectrode. The positive DC potential is ...

متن کامل

Title : 1 Direct Activation and Temporal Response Properties of Rabbit Retinal Ganglion

31 In the last decade several groups have been developing vision prostheses to restore 32 visual perception to the profoundly blind. Despite some promising results from 33 human trials, further understanding of the neural mechanisms involved is crucial for 34 improving the efficacy of these devices. One of the techniques involves placing 35 stimulating electrodes in the subretinal space between...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:
  • Investigative ophthalmology & visual science

دوره 44 8  شماره 

صفحات  -

تاریخ انتشار 2003