gms | German Medical Science

62. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie (DGNC)
Joint Meeting mit der Polnischen Gesellschaft für Neurochirurgen (PNCH)

Deutsche Gesellschaft für Neurochirurgie (DGNC) e. V.

07. - 11. Mai 2011, Hamburg

C-fos expression in the visual cortex after intracortical electrical stimulation

Meeting Abstract

  • B. Neyazi - Department of Neurosurgery, Hannover Medical School, Hannover, Germany
  • M. Alam - Department of Neurosurgery, Hannover Medical School, Hannover, Germany
  • K. Schwabe - Department of Neurosurgery, Hannover Medical School, Hannover, Germany
  • J.K. Krauss - Department of Neurosurgery, Hannover Medical School, Hannover, Germany
  • M. Nakamura - Department of Neurosurgery, Hannover Medical School, Hannover, Germany

Deutsche Gesellschaft für Neurochirurgie. Polnische Gesellschaft für Neurochirurgen. 62. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie (DGNC), Joint Meeting mit der Polnischen Gesellschaft für Neurochirurgen (PNCH). Hamburg, 07.-11.05.2011. Düsseldorf: German Medical Science GMS Publishing House; 2011. DocP 022

DOI: 10.3205/11dgnc243, URN: urn:nbn:de:0183-11dgnc2435

Veröffentlicht: 28. April 2011

© 2011 Neyazi et al.
Dieser Artikel ist ein Open Access-Artikel und steht unter den Creative Commons Lizenzbedingungen (http://creativecommons.org/licenses/by-nc-nd/3.0/deed.de). Er darf vervielfältigt, verbreitet und öffentlich zugänglich gemacht werden, vorausgesetzt dass Autor und Quelle genannt werden.


Gliederung

Text

Objective: Electrical stimulation of the primary visual cortex is used as an experimental approach for visual prostheses. The immediate-early gene c-fos is transiently expressed in neurons immediately after a variety of physiological and pharmacological stimuli. We here examined c-fos expression in different layers of the visual cortex after intracortical stimulation of layer IV of the visual cortex.

Methods: Twenty-four male Sprague Dawley Rats (250 g - 300 g) were anesthetized by intraperitoneal (i.p.) injection of chloral hydrate (3.2%, 1 ml per 100 g body weight) and placed in a stereotactic frame. After a midsagittal incision, a craniotomy was made over the visual cortex region and a bipolar electrode was placed in layer IV of the visual cortex at 7.0 mm posterior and 3.6 mm lateral to Bregma. For stimulation, four different intensities were used, i.e., 0µA (sham stimulation), 10 µA, 20 µA and 40 µA, each with 200 µs pulse width and 10 Hz frequency. Stimulation was applied for a period of four hours. Subsequently, after cardiac perfusion with paraform aldehyde, the brains were removed and immunohistologically processed for c-fos immunostaining. C-fos expression was assessed in layers I-VI of the visual cortex within a radius of 200 µm around the electrode tract.

Results: Intracortical stimulation of layer IV induced c-fos expression around the stimulation site, which was highest after 20 µA stimulation compared to sham stimulation, 10 µA and 40 µA, and most pronounced in layer II of the visual cortex. Stimulation with 10 - 40 µA did not result in increased c-fos expression of the contralateral hemisphere. C-fos expression after sham (0 µA) stimulation was similar in both hemispheres.

Conclusions: Stimulation of layer IV of the primary cortex leads to activation of layer II with saturation at 20 µA. Therefore, this low stimulation intensity may be sufficient enough for effective intracortical electrical stimulation of the primary visual cortex. These data may provide further information for the conception of intracortical visual prostheses.