The 1967 movie hit, The Graduate, featured this now famous slice of dialogue between young Benjamin Braddock and a boozy Mr. McGuire:
Mr. McGuire: I want to say one word to you. Just one word.
Benjamin: Yes, sir.
Mr. McGuire: Are you listening?
Benjamin: Yes, I am.
Mr. McGuire: Plastics.
Benjamin: Just how do you mean that, sir?
Today, at least among neurophysiologists, the new variation on that one-word notion is… “Plasticity.”
And that mean’s brain plasticity, the normal ability of synapses to strengthen and weaken in response to changing neural activityand a key component to experience-dependent brain maturation.
Pyramidal cell. A type of neuron found in the cerebral cortex, the hippocampus and amygdala. These are the primary excitation units of the prefrontal cortex and spinal tract in mammals. Recent studies on pyramidal neurons have focused on topics ranging from neuroplasticity to cognition.
“When we have experiences, connections between brain cells are modified so that we can learn,” says Ben Philpot, neuroscientist and professor of cell and molecular physiology at UNC. “By strenghening and weakening appropriate connections between brain cells, a process termed ‘synaptic plasticity,’ we are able to constantly learn and adapt to an ever-changing environment.”
A collaborative research effort from the labs of Philpot and Duke University’s Mike Ehlers, MD, PhD, adds some experimental validation to the thought that the process is disrupted in people with neurodevelopmental disorders such as autism and Angelman syndrome.
The latter is a neurogentic disorder that occurs in one in 15,000 live births. Often misdiagnosed as as cerebral palsy or autism, characteristics include cognitive and developmental delay, severe mental retardation, minimal or no use of words, seizures, sleep disturbance, hand flapping and motor and balance disorders.
In studying a mouse model of the syndrome , in which the gene Ube3a is functionally deficient, the scientists found profound impairments in neocortical synaptic plasticity, suggesting that this may contribute to the learning impairments in people with Angelman syndrome.
But the study revealed a tantalizing finding: it showed that normal brain plasticity can be restored after brief periods of sensory (visual) deprivation.
“This raises the remarkable possibility that brain cells in Angelman syndrome patients maintain a latent ability to reverse their plasticity defects,” says Philpot, thus raising the possibility of effective therapies for the disorder, behavioral, pharmacological, or genetic.
See: Yoshiro, Koji, et al, ”Ube3a is required for experience-dependent maturation of the neocortex.” Nature Neuroscience, publised online May 10, 2009.
Photo credit: Philpot lab.
Les Lang
