The Septum and Hyper‐reactivity: A Review

Abstract

The literature related to one form of septal dysfunction ‐ hyper‐reactivity ‐ is reviewed. The increase in reactivity following septal damage is considered in terms of its reliability and the many factors which influence its attenuation and release. Research discussed includes the topics of anatomical locus of septal damage, species and strain investigated, pre‐ and post‐operative handling, neurochemical factors, and the relationship of hyper‐reactivity to other septal dysfunctions and other anatomical structures.

GABAA receptor activation in the lateral septum reduces the expression of conditioned defeat and increases aggression in Syrian hamsters

“…Although lesions of the LS have long been reported to produce extraordinarly high levels of aggression in a variety of species (Albert and Richmond, 1976; Albert and Chew, 1980; Pradhan, 1975; Sodetz and Bunnell, 1970), a closer examination of many of these lesion studies is beginning to suggest that this may be an overgeneralization (Sheehan and Numan, 2000). Rather, the effects of LS lesions on aggression are complex and can depend upon the prior social experience of the lesioned animal, the time interval between lesioning and testing, and the context of social interaction (Albert and Chew, 1980; Fried, 1973; Gotsick and Marshall, 1972; Potegal et al, 1981; Sodetz and Bunnell, 1970). The present data are important because they suggest that activation of GABA A receptors in the LS can induce aggression in males irrespective of prior social experiences.…”

Effects of handling before central 6-hydroxydopamine treatment on subsequent emotionality and neurochemical changes in rats

“…Preoperative testing of normal rats, which necessitates handling, for 6 days prior to septal lesioning does not prevent the appearance of septal rage (yutzey, Meyer, & Meyer, 1967). While there have been claims that extensive (e.g., 30 days) daily handling reduces the incidence of septal rage (see Fried, 1973, for review), our work shows (Coscina et aI., 1975;present experiment) that the same amount of handling effective in curtailing 60HDA-induced rage when instituted after central injection is ineffective when 'instituted prior to injection.…”

Prolonged hyperreactivity of septal rats with intraventricular pretreatment of 6-hydroxydopamine

“…It is not clear why the discrepancy occurred. It should be pOinted out, however, that in the daily behavioral testing in this study, we first brought the forceps close to the snout of the rat and then gave the tactile stimulation, tapping the back of the animal slightly with the forceps, since the septal rat had been known to be sensitive not only to tactile stimulation but also to visual stimulation (Brady & Nauta, 1953;Fried, 1973). Coscina et al (1973) and Nakamura and Thoenen (1972) did not employ visual threats in their behavioral testing.…”

“…The depletion of these transmitter substances in diencephalon and amygdala is thought to elicit the disruption of septoamygdaloid influences on the hypothalamus. Fried (1973) postulated that septal hyperreactivity is induced by dysfunction in the septoamygdalohypothalamic neural circuit. Gage and Olton (1976) reported that L-dopa, a metabolic precursor of catecholamines, reduced septal hyperreactivity.…”