无论神经元是感觉性的还是运动性的,大
的或是小的,都有一个共同特点:它们的活动
是电子性和化学性的。神经元互相合作和竞
争去调控神经系统的整体状态, 就象人们在
决策过程中的合作与争斗。在树突接受到的
来自与其相联接的轴突发出的化学信号被变
换成电子信号,它加强或减弱所有其它突触上
的电子信号,从而做出决定是否将信号传到别
处。电子电位会移行到轴突, 传到下一个相
联接的神经元树突上的突触, 这个过程反复
进行
At their narrowest points, calcium ion channels are
less than a nanometre in diameter (
Cataldi et al. 2002).
This extreme smallness of the opening in the calcium
ion channels has profound quantum mechanical
implications. The narrowness of the channel restricts
the lateral
spatial dimension. Consequently, the lateral
velocity
is forced by the quantum uncertainty principle to
become large. This causes the
quantum cloud of
possibilities
associated with the calcium ion to fan out
over an increasing area as it moves away from the tiny
channel to the target region where the ion will be
absorbed as a whole, or not absorbed at all, on some
small triggering site.
No comments:
Post a Comment