Word: neural
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...intact unit. Even the slightest fraying of the cord can interrupt or weaken signals traveling from the brain to the muscles, in some cases resulting in paralysis. To bridge these gaps in the tapestry of nerve cells, you have to either coax existing neurons to grow across the neural divide or introduce new cells to replace the damaged ones. Often the two strategies feed off each other: the growth of existing neurons stimulates the sprouting of new nerve cells, and those actively developing cells provide older ones with the right cellular environment to jump-start their own growth...
...evolution of mammals. But their analysis, reported last week in Nature, indicated a subtle genetic shift in the human family tree within the past 200,000 years. "The gene seems to trigger the development of the ability to move the mouth, lips and tongue as well as certain neural processes," says Wolfgang Enard, one of the study's German authors...
WHAT IT DOES: One of the brain's emotional centers; helps in the recognition of facial expressions and tones of voice. Neural transmissions increase in response to emotional stimuli. Normally, repeated exposure to the same experiences or images leads to habituation, or reduced response...
...journey begins when a rat (we'll get to humans later) feels the stress, in this case an electric shock. The rat's senses immediately send a message to the central portion of its brain, where the stimulus activates two neural pathways. One of these pathways is a relatively long, circuitous route through the cortex, where the brain does its most elaborate and accurate processing of information. The other route is a kind of emergency shortcut that quickly reaches an almond-shaped cluster of cells called the amygdala...
Discovering this basic neural circuitry turned out to be a key breakthrough in understanding anxiety. It showed that the anxiety response isn't necessarily caused by an external threat; rather, it may be traced to a breakdown in the mechanism that signals the brain to stop responding. Just as a car can go out of control due to either a stuck accelerator or failed brakes, it's not always clear which part of the brain is at fault. It may turn out that some anxiety disorders are caused by an overactive amygdala (the accelerator) while others are caused...