Factors influencing frontal cortex development and recovery from early frontal injury

Abstract

Background: Neocortical development represents more than a simple unfolding of a genetic blueprint but rather represents a complex dance of genetic and environmental events that interact to adapt the brain to fit a particular environmental context. Although most cortical regions are sensitive to a wide range of experiential factors during development and later in life, the prefrontal cortex appears to be unusually sensitive to perinatal experiences and relatively immune to many adulthood experiences relative to other neocortical regions.

Methods and results: One way to examine experience-dependent prefrontal development is to conduct studies in which experiential perturbations are related neuronal morphology. This review of the research reveals both pre- and post-natal factors have important effects on prefrontal development and behaviour. Such factors include psychoactive drugs, including both illicit drugs and prescription drugs, stress, gonadal hormones and sensory and motor stimulation. A second method of study is to examine both the effects of perinatal prefrontal injury on the development of the remaining cerebral mantle and correlated behaviours as well as the effects of post-injury rehabilitation programmes on the anatomical and behavioural measures.

Conclusions: Prefrontal injury alters cerebral development in a developmental-stage dependent manner with perinatal injuries having far more deleterious effects than similar injuries later in infancy. The outcome of perinatal injuries can be modified, however, by rehabilitation with many of the factors shown to influence prefrontal development in the otherwise normal brain.

Figure 1

A neuron from the Cg 3 region of the medial prefrontal cortex of a rat.

Figure 2

The effects of prenatal stress on dendritic length. *Differs significantly from control.

Figure 3

Effects of antipsychotic drugs administered from post-natal day 3 to 10 on dendritic length.

Figure 4

Effects of vitamin supplements on recovery from medial prefrontal lesions on post-natal day 3 in rats. (a) Performance on the Morris water task. (b) Dendritic length in perilesional cortex.