Natural Selection on Hippocampal Circuitry Underlying Exploratory Behaviour in Mice: Quantitative-Genetic Analysis

Behaviour is an animal's way of interacting with its environment and it is therefore a prime target for natural selection. As behaviour is the output of an animal's nervous system, this indirectly leads to selection pressures on neuronal structures. In consequence, each species' behaviour and nervous system have co-evolved in the context of its natural habitat and can be properly comprehended only when their interrelationships are regarded against that background [7]. This notion implies that to arrive at a profound understanding of neurobehavioral traits, one will have to consider problems of causation. Van Abeelen [59] distinguished between the phenogenetic and the phylogenetic aspects of causation. Both concern the genetic correlates of neurobehavioral traits, the first in a gene-physiological, the latter in an evolutionary sense. Stated otherwise, neurobehavioral geneticists attempt to uncover the physiological pathways underlying the expression of a trait and to provide an answer to the question of what exactly is the adaptive value of this trait for the organism. As I have argued before [12, 13], quantitative-genetic methods may be employed with profit to address problems related to both aspects of causation. As an illustration of this research strategy, I present here the results of some experiments concerning mouse exploratory behaviour and hippocampal neuroanatomy