Assessing the pathological extent of aggressive behaviour in dogs. A review of the literature

Increased Number of Neurons Expressing Androgen Receptor in the Basolateral Amygdala of Pathologically Aggressive Dogs

“…The control group consisted of seven dogs which had no history of aggressive incidents, anxiety or obsessive compulsive disorders. The aggressive group contained six dogs that were selected based on their altered aggression sequence, as proposed by Jacobs et al. (2003), and a history of attacking without warning was the main requirement.…”

“…In rhesus monkeys it was shown that the amygdala also plays an important role in hierarchical or dominance aggression (Bear et al., 2001). Because castration is often applied as a therapy to reduce aggression in dogs, determining the role of AR in the amygdalar modulation of pathological canine aggression, defined by an altered aggression sequence (Jacobs et al., 2003), may provide information concerning the potential benefit of castration as a treatment for this specific aggression type. The present study was restricted to intact male dogs because the physiological background of aggression differs between the sexes.…”

Brain, Craniofacial, and Dental Lesions of a Free-ranging Gray Wolf (Canis lupus) Implicated in a Human Attack in Minnesota, USA

“…The lesions in the wolf's brain affecting olfactory bulbs, peduncles, and tracts and pyriform and frontal cortices suggest severe damage to the areas and circuitries associated with cognitive function, emotion, and olfaction. This conclusion is supported by naturally occurring and experimentally induced lesions in the frontal cortex and secondary circuitry remodeling to the limbic system in domestic canines that have demonstrated changes in behavior, probability-based prediction, inhibition, aggression, maintenance, and manipulation of complex learning, and spatial and conceptual memory (Jacobs et al 2003;Christie et al 2008). It has been theorized that wolves use spatial memory and learning to help locate geographically disparate prey (Hiestand 2011).…”

“…The facial changes may have also altered the wolf's communication abilities, communications that govern pack social behavior and survival. For example, eight facial expressions enable wolves to make fine discriminations of the mood and intent of conspecifics within a pack (Jacobs et al 2003). Thus, this wolf's impairments, leading to adaptive survival strategies, may be one of the factors that triggered this attack, but not the primary cause.…”

“…Similar functional changes are demonstrated in other species, including humans who suffer from genetic disorders and acute and chronic traumatic brain injuries in the frontotemporal region (Anderson et al 2006). Minimal injury is needed to produce these changes, although reported damage ranges from focal, microscopic alteration to complete removal (Jacobs et al 2003;Anderson et al 2006;Christie et al 2008;Morales-Medina et al 2013). Furthermore, olfaction is crucial and provides data about prey, danger, and other wolves' identity; sex; breeding condition; social status; emotional state; age; condition; and diet (Harrington and Asa 2003).…”