Word: cortexes
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...gatekeeper of sensory information, the hippocampus is it. The aroma and sizzle of bacon frying, the smooth finish of polished granite, a phone number you need to call--all must pass through the hippocampus. Only if information gets in can it be moved along to the prefrontal cortex, where it will be held briefly in what is called working--or short-term--memory. When you look up the phone number, dial it and promptly forget it, that's your prefrontal cortex working in tandem with your hippocampus...
...hippocampus begins to malfunction early in Alzheimer's disease. Imaging studies have shown that people with Alzheimer's typically have smaller than average hippocampi. Meanwhile, as the hippocampus is shrinking, the pathway between it and the prefrontal cortex also begins to degrade. Signals peter out and fade away, and questions take their place: Do I know you? Who am I? But it's not just with Alzheimer's: the hippocampus also goes at least somewhat awry in normal memory loss. "It's relatively stable in volume till about 60," Harvard neuroscientist Randy Buckner explains, "and then begins to change. People...
...Small's hunch--now proven--was that a node of the hippocampus different from the one affected in Alzheimer's was breaking down in normal memory loss. "In humans, monkeys and rats," he says, "normal aging targets a node called the dentate gyrus, while a different node--the entorhinal cortex--is relatively spared. But in Alzheimer's disease, it's almost exactly reversed." Small has gone deeper, pinpointing a protein molecule known as RbAp48 that is lower in the brains of people suffering ordinary age-related memory loss. He and his colleagues are now testing the effect of that molecule...
...Moral Brain Scientists are overreaching if they think their mapping of the human brain explains moral behavior [Dec. 3]. If one section of the cortex "lights up" when we are solving dilemmas that engage us emotionally, and another when we are making cool, rational judgments, so what? The observed brain activity may help to tell us how we act and react, but that is very different from telling us why. The moral drive within us is not so easily explained. Alasdair Livingston, Adelaide
Statements like "2 + 2 = 5" and "Torture is good" caused an area called the anterior insula to light up. True statements like "2 + 2 = 4" activated the ventromedial prefrontal cortex. The ventromedial is thought to play a role in judgment, memory, fear and, according to one study, soft-drink preferences. The anterior insula helps process fear, disgust and reactions to bad smells...