ELECTRO-PHYSIOLOGICAL ANALYSIS OF RETRIEVAL OF CONDITIONED TASTE-AVERSION - PHYSIOLOGICAL TECHNIQUES AND DATA-PROCESSING

  • 1 January 1979
    • journal article
    • research article
    • Vol. 28  (6) , 537-544
Abstract
New techniques suitable for electrophysiological investigation of retrieval of conditioned taste aversion [CTA] were developed. The gustatory discrimination apparatus consisted of 2 parallel drinking spouts [20 mm apart] equipped with photoelectric lick sensors. The spouts contained water or the aversive fluid [0.15 M LiCl], respectively, and their position could be rapidly [50 ms] interchanged with a reversive electromotor. Licking at either spout and the position of the fluids were recorded on one channel of a tape recorder. Unit activity was picked up with W microelectrodes [40 .mu.m] inserted into the brain of a freely moving rat with a head-mounted microdrive system [weight 2 g], fixed to an implanted guiding cannula. The electrode was connected through a head-carried FET [field effect transistor] signal follower to a wide band integrated circuit amplifier and the unit activity was recorded in the other channel of the tape recorder. The records were evaluated using an off-line computer program [LINC 8] consisting of a spike detection subroutine followed by amplitude histogram analysis. The mean [M] and SD values were computed for uni- or bimodal amplitude distributions of the principal spike components. Spikes falling within the M .+-. 2 SD range of the selected parameter were identified as single units and used for construction of post-stimulus histograms triggered by licking or by spout switching.