A paper published online in Nature (Vol. 442, No. 7105, 24 August 2006) helps to explain how briefly depriving the brain of visual stimulation has profound effects on its ability to process visual information.
Neuroscientists have long known that animals that grow up with one eye covered during a critical period of brain development lose some of their visual acuity and ability to respond to certain visual stimuli. Gina Turrigiano and colleagues covered the eyes of young rats for several days and, by measuring the electrical activity of neurons in layer 4 of the brain cortex, showed that this boosts electrical activity at synapses between two types of cortical neurons: fast-spiking basket cells and star pyramidal neurons. The visual deprivation causes star pyramidal neurons to excite the fast-spiking basket cells, which then feed back and inhibit the star pyramidal neurons.
The team also documents a novel type of long-term potentiation of inhibition (LTPi) - a long-lasting increase in inhibition between the two neuron types. The results suggest that this type of LTPi is important for fine-tuning our brain connections in response to what we see.
Gina Turrigiano (Brandeis University, Waltham, MA, USA)
Abstract available online.
(C) Nature press release.
Message posted by: Trevor M. D'Souza