Cholinergic Potentiation of Restoration of Visual Function after Optic Nerve Damage in Rats

Figure 1

Experimental design. The study was performed over a period of 11 weeks: 5 weeks for the learning of the behavioural task training—VIST training, double-end arrow (a), 1 week for the baseline VEP recording (b) and the crush surgery (c), and 4 weeks for the repetitive behavioural and electrophysiological testing (d). Thallium autometallography (TlAMG) (e) was done one week after the last testing session. (a) The VIST test consisted of the detection of a bright stimulus (light gray square) among 6 openings (5 black and 1 gray square) on a touch screen. (b) When all rats reached an adequate brightness discrimination performance and success rate, electrodes (black dots) were implanted in the visual cortex (V1), the superior colliculus (SC), and in the nose bone (Ref.) in the brain/skull of the rats, together with a headstage to fix visual stimulation goggles (gray circles). A potential evoked by flash displayed through the goggles (VEP, red tracing) was recorded and set as a baseline. (c) Then animals were divided into three experimental groups: sham, ONC/DPZ, and ONC/saline, and bilateral partial optic nerve crush (ONC) or sham surgery was performed. (d) DPZ (1 mg/kg then 0.5 mg/kg) or saline i.p. injections were performed each day for the first 2 weeks post-ONC (black arrows) then once a week. VIST testing (3 times a week during 4 consecutive weeks) and the VEP recording (once a week during 4 consecutive weeks, red tracing) were performed. (e) One week after the end of the VIST testing and the jugular vein catheter implantation, the neuronal activity was measured by thallium autometallography (TlAMG).

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