Over the next three months, the Dana Foundation blog is pleased to host a new blog series, “Tales from the Lab,” featuring two neuroscience graduate student guest bloggers: Tim Balmer from Georgia State University and Grace Lindsay from Columbia University. Tim’s contributions will focus on life as a neuroscience graduate student and Grace will focus on neuroplasticity. This is Grace’s first blog in the series.
Infancy is a tumultuous time for the brain. A set of neurons with connections in constant flux are working to process an onslaught of sensory signals; yet the connections themselves are guided by the very signals they’re processing. Despite the apparent chaos, we all end up with roughly the same hardware: an occipital lobe for seeing, a temporal lobe for hearing, parietal lobe for sensing touch, etc.
But what happens when those brain-shaping signals can’t get into the brain? For example, in the case of Leber’s congenital amaurosis (LCA), a genetic mutation disrupts the function of cells in the eye, leaving people with LCA essentially blind from birth. This lack of visual input throws a wrench into the brain’s normal plan of development, and it shows in the brain anatomy of adults with these kinds of disorders. Without visual information to process, the occipital lobe is reassigned to other tasks. PET and fMRI studies of congenitally blind humans have shown activation of the occipital lobe during processing of sounds, smells, and touch (such as braille). Such activation is not seen when imaging the brains of sighted people, or even those who lost their vision later in life. These findings demonstrate the remarkable plasticity of the developing brain to adapt its activity and structure in order to best process the signals it receives.