Cortical plasticity within and across lifetimes: how can development inform us about phenotypic transformations?

Abstract

The neocortex is the part of the mammalian brain that is involved in perception, cognition, and volitional motor control. It is a highly dynamic structure that is dramatically altered within the lifetime of an animal and in different lineages throughout the course of evolution. These alterations account for the remarkable variations in behavior that species exhibit. Of particular interest is how these cortical phenotypes change within the lifetime of the individual and eventually evolve in species over time. Because we cannot study the evolution of the neocortex directly we use comparative analysis to appreciate the types of changes that have been made to the neocortex and the similarities that exist across taxa. Developmental studies inform us about how these phenotypic transitions may arise by alterations in developmental cascades or changes in the physical environment in which the brain develops. Both genes and the sensory environment contribute to aspects of the phenotype and similar features, such as the size of a cortical field, can be altered in a variety of ways. Although both genes and the laws of physics place constraints on the evolution of the neocortex, mammals have evolved a number of mechanisms that allow them to loosen these constraints and often alter the course of their own evolution.

Individual differences in cortical connections of somatosensory cortex are associated with parental rearing style in prairie voles (Microtus ochrogaster)

“…Of course, genes play an important role in how the neocortex differentiates into distinct areas with specific patterns of connectivity (Krubitzer and Dooley, 2013; O'Leary and Sahara, 2008; Rash and Grove, 2006). However, cross-fostering work in rats (Francis et al, 1999), and voles (Perkeybile et al, Submitted), indicates that subsequent social behavior and the type of parenting style that the offspring ultimately adapt are based on how they were reared (LC versus HC) rather than the biological relationship to the parent.…”

Prenatal Brain-Body Allometry in Mammals

“…Changes to peripheral systems during early neurodevelopment have been shown to induce dramatic changes to cortical organization and connectivity [Krubitzer and Dooley, 2013]. Both the degree and early emergence of primate prenatal encephalization make it a good candidate for such epigenetic changes, though it remains unclear which if any of the differences in primate brain connectivity (e.g.…”

Phantom Limbs, Neuroprosthetics, and the Developmental Origins of Embodiment

“…Although the developmental plasticity inherent in the sensorimotor system enables functionality in individuals with atypically formed bodies, it is also essential for the everyday process of adapting to the increases in limb size, shape, and strength that characterize typical development across a diversity of species, including those with extreme morphological and behavioral specializations [43]. …”