In spring, days grow long, and the white-footed mouse looks for a mate. For some mammals, day length prompts behaviors like breeding or camouflaging, and scientists say it's not just the arc of the sun that kicks off these seasonal events; substances in the brain also play a part. One important element is melatonin, a hormone that the mammalian brain secretes at night. According to a...
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Drugs affect different people in different ways. Take cocaine for example. Not only does the drug have a stronger impact on the behavior of individuals with a particular genetic makeup, it also initiates more profound changes in their brains. Researchers at the University of Michigan are studying brain plasticity in cocaine-treated rats after a period of abstinence. They're studying how abstinence from the drug affects different...
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Sensory stimuli are all around us. Street traffic zooms by. A neighbor waves “hello.” A co-worker taps away at his keyboard. Each sight, sound, and motion ignite action within our brains. But even without all these stimuli, the brain is always active. Known as “spontaneous activity,” the activity happening inside the brain in the absence of direct stimuli follows a pattern of up and down states...
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Life's little pleasures often elude those suffering from depression, including rats, who show little interest in sugar water after experiencing stress. This behavior leads scientists to speculate that the illness might be characterized by a defect in the brain's neural reward circuit. Recent research focuses on a key element of this circuit – the nucleus accumbens (NAc), part of the brain region known as the ventral...
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Scientists hypothesize that seizures occur because brain cells fire in places they're not supposed to. Dentate granule cells (DGCs), a type of neuron born throughout adulthood, sometimes migrate into a different region of the dentate gyrus, a part of the hippocampus. These abnormal newborn cells sprout axons called “mossy fibers” that form connections with neighboring DGCs in the inner molecular layer, causing synaptic changes that...
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What does it take to survive that tumultuous time called adolescence? Good friends, exercise, and new brain cells. Scientists at Michigan State University found evidence of neurogenesis in the brains of adolescent hamsters, according to a study published last month in PNAS. The new cells, which became integrated into neural circuits in adulthood, were discovered in the amygdala and connected limbic regions – areas associated with...
Read More There's a lot to be said for being in the right place at the right time. For a neuron, emerging at a certain place within the brain destines it for a particular function. A new study posits that, for a group of cells in the hippocampus, it's not only where a neuron is born, but also when it is born, that defines the specific roles...
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A monkey spots a mango and part of its brain lights up. The action takes place in the inferior temporal cortex, part of the brain that's essential to object recognition. Using retrograde tracing and anatomical imaging, scientists at the National Institute of Neuroscience, and the RIKEN Brain Science Institute in Japan identified two interwoven, yet distinct, systems within the region's complex circuitry. “Our anatomical findings provide evidence...
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Revving engines, blasting sirens, the drummer next door. Despite the myriad sensory stimuli going on around us at any given moment, humans have the ability to stay focused on the task at hand. This skill is due to a part of the brain known as the neocortex, a six-layer structure whose intricate wiring is largely a mystery. But researchers at the University of Virginia just...
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At first, all appears normal with the infant's development. But one day, around her first birthday, she stops making eye contact, her babbling comes to an end, she wrings her hands, and holds her breath. The child will likely survive into adulthood, but with Rett syndrome, she will lead a life with severe disabilities. The symptoms of this autism-related disorder are complex, and treatments are not...
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