Hahnloser R H R
Bell Labs 1C-456, Lucent Technologies, 600 Mountain Avenue, Murray Hill, NJ 07974, USA.
Neuroscience. 2003;120(3):877-91. doi: 10.1016/s0306-4522(03)00201-x.
Head-direction (HD) cells in subcortical areas of the mammalian brain are tuned to a particular head direction in space; a population of such neurons forms a neural compass that may be relevant for spatial navigation. The development of neural circuits constituting the head-direction system is poorly understood. Inspired by electrophysiological experiments about the role of recurrent synaptic connections, we investigate a learning rule that teaches neurons to amplify feed-forward inputs. We simulate random head movements of a rat, during which neurons receive both visual and vestibular (head-velocity) inputs. Remarkably, as recurrent connections learn to amplify exclusively the visual inputs, a neural network emerges that performs spatio-temporal integration. That is, during head movements in darkness, neurons resemble HD cells by maintaining a fixed tuning to head direction. The proposed learning rule exhibits similarities with known forms of anti-Hebbian synaptic plasticity. We conclude that selective amplification could serve as a general principle for the synaptic development of multimodal feedback circuits in the brain.
哺乳动物大脑皮层下区域的头部方向（HD）细胞会被调整到空间中的特定头部方向；一群这样的神经元形成了一个可能与空间导航相关的神经罗盘。构成头部方向系统的神经回路的发育情况仍知之甚少。受关于递归突触连接作用的电生理实验启发，我们研究了一种教导神经元放大前馈输入的学习规则。我们模拟了大鼠的随机头部运动，在此期间神经元接收视觉和前庭（头部速度）输入。值得注意的是，随着递归连接学会专门放大视觉输入，一个执行时空整合的神经网络出现了。也就是说，在黑暗中头部运动期间，神经元通过保持对头部方向的固定调谐而类似于HD细胞。所提出的学习规则与已知形式的反赫布突触可塑性表现出相似性。我们得出结论，选择性放大可能是大脑中多模态反馈回路突触发育的一般原则。
