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All fired up

发布时间:2019-03-08 04:20:14来源:未知点击:

By Jonathan Knight in Princeville, Hawaii TENNIS players often improve their game after the first set. Part of the reason, say Canadian researchers, is that neurons controlling muscles “warm up” and prepare to fire before they are called upon. Activities such as tennis require the eyes to make rapid movements. When the tennis ball appears on the retina, a brain region called the superior colliculus directs the eye to bring the ball into the centre of the field of view. To study this, Douglas Munoz and his colleagues at Queen’s University at Kingston, Ontario, recorded the activity of neurons in the superior colliculus of a monkey. The animal was trained to stare at a point of light and then, as the light went out and another came on, to turn its eyes towards the second light. As expected, if the new light came on in the field of the retina corresponding to a monitored neuron, the instruments recorded an increase in voltage that culminated in the neuron firing. After a number of repetitions, the voltage in the monitored neuron rose every time the first light went out, even before the second light came on. If the second light struck another part of the retina, the activity in the nerve cell died away before it fired. “This activity warms up the neuron so it can respond faster,” says Munoz. People do many things faster after a few tries, so the effect is likely to be a general property of neurons controlling movement. “As soon as we saw it, it made sense.” More on these topics: