No abstract

Local anesthesia of the facial epidermis can effect a substantial decrease in shock-elicited fighting of paired rats. The present experiments constitute methodological extensions to mouse killing and spontaneous drug-induced social aggression. In the first experiment, known mouse-killing rats were given bilateral lidocaine or placebo injections administered under ether anesthesia. Attack and kill latencies were significantly longer under lidocaine than under placebo; all subjects killed under placebo, whereas a third of all subjects failed to kill on the initial lidocaine test. On subsequent lidocaine testing, latencies decreased and nonkilling rats killed. In a second experiment intense apomorphine-induced conspecific fighting of rats preselected for aggressiveness was markedly reduced following lidocaine anesthesia. The comparative results of both experiments are interpreted in reference to theoretical assertions regarding the import of sensory information in stimulus-bound attack and the typology of central aggression systems.

Selected pairs of agressive rats fighting reliably and at relatively high levels were successively treated with lidocaine anesthesia of the vibrissal pads prior to each daily test session. The initial decrement in fighting was substantial, but after only three sessions pretest level of fighting was regained. Initial decrease in fighting of a second group following removal of all vibrissae was comparable to that produced by local anesthesia, but recovery of fighting to pret~st levels was slower and less complete. The results suggest that intact and functional vibrissal organs are not mandatory for normal fighting when Ss are given sufficient preliminary fighting experience to footshock. Applications of vibrissal sensory deprivation techniques for control of fighting in experimental designs calling for repeated measures or sequential treatments are potentially liable to confounding.Historically, investigators have long recognized the import of rodent vibrissal organs in providing proximal sensory information. Early monographs by Richardson (1909) and Vincent (1912) reveal interests stemming from reports of successful maze performance by blind and anosmic rats and the presumed interactive roles of the senses as defined by characteristics of the experimental task . Watson (1907) compared the maze performance of blind, anosmic, and normal rats before and after being devibrissaed . Although immediate performance was im paired, no decrement in running time was observed 24 h after being devibrissaed; Watson concluded that removal of the vibrissae had no effect when sufficient time was allowed for adaptation. Richardson (1909) also found that tactual sensation from the vibrissae was unnecessary after learning had occurred in a platform jumping task.More recently, Schiffman, Lore , Passafiume, and Neeb (1970) tested hooded and albino rats on a visual cliff apparatus providing both visual and tactual depth cues. Devibrissaed rats showed a marked preference for descent on the shallow side of the visual cliff, whereas intact controls showed no significant preference for either side. Rats apparently do not apply visual information unless forced t6 do so by a center-board height preventing vibrissal contact with the glass surfaces. Tactual information from the vibrissae may thus be prepotent over visual information on this depth-perception test. Schiffman et al (1970) suggested that visual discrimination on a number of visual tasks may be substantially improved by removal of the vibrissae.

No abstract

Local anesthesia of the mystacial epidermis with Lidocaine HCl reliably decreased shock-elicited fighting in 8 pairs of mature male Long-Evans rats. The decrease in aggressive responding was approximately twice as great as that reported for devibrissaed rats. Subsequent fighting, 3-hr. post-injection, did not differ from control or pre-injection baselines. Recording of intense vocalization accompanying fighting yielded objective data comparable to attack scores visually observed and allowed an independent measure of depressed fighting behavior. The results are discussed in reference to the import of tactual orientation for guiding directed attack and the relative merits of the technique as a vehicle for further investigation.