Conceptual and Methodological Problems Associated with the Study of Brain Mechanisms Underlying Aggressive Behaviour

Genetically Defined Animal Models of Neurobehavioral Dysfunctions

“…However, it has been suggested that different biological mechanisms may be involved in the killing and eating of prey by mice (Ebert and Green, 1984;Whelton and O'Boyle, 1977). In contrast, there is extensive information on the neural basis, endocrinology, and pharmacology of predatory behavior in rats (Karli, 1981;Karli et al, 1969Karli et al, , 1974Olivier et al, 1989) andin cats (Mirsky and Siegel, 1991;Siegeland Brutus, 1990).…”

Is the concept of ‘personality’ relevant to the study of animal aggression?

“…The thus elicited aggression is clearly instrumental behaviour. As a matter of fact, once the rat has learned to stop the brain stimulation by pressing a lever (switch-offresponse), it is quite difficult to still induce it to kill a nearby mouse (Karli, Eclancher, Vergnes, Chaurand and Schmitt, 1974;Karli, 1981Karli, , 1987.…”

“…Now studies investigating the neurobiological bases of learning and memory strongly suggest that it is the amygdala which encodes, stores, and retrieves affective-rewarding or aversive-attributes, while another+losely related-structure of the temporal lobe, namely the hippocampus, encodes the environmental context-in particular, spatial-temporal attributes-of the same specific memory (Kesner, 1981 ;Kesner and Hardy, 1983). It is quite understandable, therefore, that bilateral lesions of the amygdala were shown in many instances to attenuate greatly the emotional responsiveness and the sensitivity to any kind of social stimulation, thereby markedly reducing the probability of intra-as well as inter-specific aggressive responding (see Karli, 1981Karli, , 1987.…”

Perception, Cognition and Action: The Mediating Role of Affective States

“…The amygdala most prob ably encodes, stores and retrieves affective -reward ing or aversive -attributes, while the hippocampus encodes the environmental context -in particular spatial-temporal attributes -of the same specific memory. It is quite understandable, therefore, that bilateral amygdaloid lesions were shown in many in stances to greatly attenuate the emotional responsive ness and the sensitivity to any kind of social stimula tion, thereby markedly reducing the probability of intra-as well as interspecific aggressive responding [Karli, 1981]. In primates, the amygdala closely inter acts with the limbic portions of the prefrontal cortex, and the cognitive-affective interplay at the cortical le vel has an essential part in both the evaluation of the contextual significance of the partners' affective be haviours and the use of such behaviours so as to dia logue with them in an adapted and efficient way.…”

“…one of the potential means of a behavioural repertoire, be realized depends basically on the way in which the situation -or rather the individual relation ship to that situation -is perceived and interpreted, it is of interest to consider the following closely related points: (1) the role played by the individual level of excitability and emotional responsiveness; (2) the manifold processes and mechanisms through which affective connotations are generated that enrich the perception, orient the resulting behaviour, and then get possibly modulated by the consequences that are actually derived from that behavioural response; and (3) the major impact of experiential determinants on the generation of affective states and of the social be haviours that reflect them. Obviously, no more than a few arbitrarily selected facts can be briefly examined [Karli, 1981, for further facts and references].…”