Understanding and Preventing Violence, Volume 2: Biobehavioral Influences (1994)
Chapter: NEUROCHEMISTRY AND NEUROPHARMACOLOGY OF AGGRESSION AND VIOLENCE
the difficulties of these categorical schemes; since variants of this behavior have been referred to as a form of "predatory aggression" (ethological) or "irritable aggression" (aversive environmental manipulations), it may be produced by brain stimulation or brain lesions (brain manipulations) and it may be self-reinforcing as in the case of "excess'' killing. The attempt to assign biologic functions to animal models of aggression demonstrates the ambiguities associated with most of these models (last column in Table 1), and the difficulties in relating many types of animal aggression to the phenomena of human violence, as defined legally or clinically, are important for the present discussion.
CONCLUDING STATEMENT
Clinical and preclinical definitions of violent and aggressive behavior range across a variety of behavioral phenomena that differ in terms of distal and proximal antecedents, intensity and frequency of behavioral acts, and functions. During the past 15 years, animal aggression research, influenced by an ethological framework, has begun to focus on adaptive patterns of behavior in biologically meaningful contexts, while clinical research is concerned with aggressive and violent acts as "behavioral pathologies," viewing aggression alternatively as a trait or a state. In order to trace the evolutionary origins of aggressive behavior at the behavioral, physiologic, and neurobiologic levels, detailed functional and structural analyses at each level are needed; this need is particularly acute at the behavioral and diagnostic levels.
NEUROCHEMISTRY AND NEUROPHARMACOLOGY OF AGGRESSION AND VIOLENCE
Until the development during the last decade of microdissection and imaging techniques for neural tissue, as well as techniques for in vivo microdialysis and improved sensitivity of biochemical assay, the evidence for the involvement of ACh, gamma-aminobutyric acid (GABA), NE, DA, and 5-HT in neural mechanisms of animal aggression was based entirely on single measures that summarized an experimental subject's entire brain activity at one time point. In humans, access to the central nervous system (CNS) is even more limited, so clinical researchers have relied on more readily collected indirect measures such as blood and urine; a somewhat more invasive technique is spinal
