New understanding of the machinery of...( The flinch is a critically important pr...)

The flinch is a critically important protective mechanism by which animals and humans instantly protect themselves against threats ranging from an attacking predator to an incoming golf ball. Researchers Michael Graziano and Dylan Cooke have shed new light on the neural machinery that controls flinching by dialing the response up or down using drugs.

Their studies concentrated on a region of the motor cortex they have dubbed the polysensory zone, which Graziano and other researchers had shown could be induced to trigger flinching by electrical stimulation.

However, Graziano and Cooke sought to test the hypothesis that the polysensory zone controls the natural behavioral flinch; motor cortex is usually not thought to control full, natural movements. To do this, they investigated how increasing or decreasing neuronal activity in the region affected the flinch response.

In their experiments with monkeys, the researchers targeted the region with drugs that either enhanced or reduced neuronal activity. They then recorded how the monkeys responded to a mild puff of air to the face.

The researchers found that the activating drugs enhanced the flinch response--which included a squint, a blink, lifting of the upper lip, flattening of the ears, and a protective arm and shoulder movement.

Flinching consists of two phases--an initial, general startle response, followed by a longer defensive response more directed toward protection from a threat. By measuring the electrical activity of the animals' eye muscles during the response, the researchers could follow it in greater detail. Significantly, they found that the initial startle response was unaffected by the drug, as were the nondefensive movements the animals made between trials. Only the sustained, directed phase of the flinch was affected.

Conversely, the researchers found that a drug that reduced neuronal activity in the polysensory zone selectively reduced the sustained,
'"/>

Contact: Heidi Hardman
hhardman@cell.com
617-397-2879
Cell Press
18-Aug-2004

Page: 1 2
Related biology news :

1. Analysis of biological clock may lead to greater understanding of human disease
2. Breakthrough in understanding of hereditary disease of lymphatic vessels
3. New model can aid in understanding immune system diseases
4. Researchers develop better understanding of immune response to viral infection
5. Access to DNA secrets yields better understanding of genes, possible tool for disease diagnosis
6. Whole body imaging allows better understanding of the immune system
7. Albany high school student adds to understanding of breast cancer gene
8. Researchers make major gain in understanding how prions jump species
9. Rb proteins role in retina development is key to understanding devastating eye cancer
10. Scientists findings may lead to better understanding of how that sleep develops, matures
11. New understanding of why brain cells die after stroke will lead to development of new treatments