NEURONAL STRUCTURE AND FUNCTION IN A SENSORY PROCESSOR

目标是了解神经网络如何处理生物相关的 感官信息和协调适应性行为反应。 的 鱼的电感觉被选为模型系统，因为，尽管 它相对简单，它与听力共享基本设计原则， 高等动物的视力 我们想继续在细胞内研究 神经元在中脑区的弱电鱼，以联系 生理响应特性的形态特征。 电鱼评估振幅和相位的调制 由于自身电干扰而产生的电信号 器官放电（EOD）与邻居的。 相似，但空间上 相位和幅度的变化调制是由移动物体引起的， 并且这样的物体的检测可能因此受到干扰 EOD。 就像猫头鹰的听觉系统一样，相位和振幅 信息由独立的神经元通道编码和处理， 中脑的水平。 然后，将这两种形式的信息结合起来， 控制行为反应。 生理上鉴定的神经元通过细胞内注射进行标记 的HRP或荧光黄，并在光学显微镜下研究， 以确定它们的形态特征，例如层流位置 胞体、树突组织和投射靶点。 我们将 试图将树突形态的差异与 在功能特性中，例如对相位或振幅的灵敏度 调制，对相位的时空调制的敏感性， - 表征移动物体的影响的幅度，以及 目标探测易受干扰。 特别感兴趣的是：1）神经元的第5和第7层的 中脑圆枕似乎只接收到 程度，他们的树突侵入层6，相位信息 信号的相位差异 从身体表面的不同部分传递的信号被计算。 2)层流 检测移动物体的总神经元的位置和形态， 也对具有特定频率关系的干扰信号敏感 动物自己的爆炸物处理装置

The goal is to understand how neural networks process biologically relevant sensory information and orchestrate adaptive behavioral responses. The electric sense of fish has been chosen as a model system since, in spite of its relative simplicity, it shares basic design principles with hearing and vision in higher animals. We want to continue intracellular studies of neurons in the midbrain region of weakly electric fish in order to relate physiological response properties to morphological features. Electric fish evaluate modulations in the amplitude and phase of the electric signal that results from the interference of their own electric organ discharges (EODs) with those of neighbors. Similar, but spatially varying modulations in phase and amplitude are caused by moving objects, and the detection of such objects may thus be impaired by interfering EODs. Much as in the auditory system of the owl, phase and amplitude information are coded and processed by separate neuronal channels up to the level of the midbrain. Both forms of information are then combined for the control of behavioral responses. Physiologically identified neurons are labelled by intracellular injection of either HRP or Lucifer Yellow and studied under the light microscope in order to determine their morphological features, such as laminar location of somata, dendritic organization and targets of projection. We will attempt to correlate differences in dendritic morphology with differences in functional properties, such as sensitivity to either phase or amplitude modulations, sensitivity to spatio-temporal modulations of phase and amplitude that characterize the effects of moving objects, and vulnerability of object detection to jamming. Of particular interest are: 1) Neurons of laminae 5 and 7 of the mesencephalic torus that appear to receive phase information only to the extent that their dendrites invade lamina 6, where phase information arrives from the hindbrain and where differences in the phase of signals relayed from different parts of the body surface are computed. 2) Laminar location and morphology of total neurons that detect moving objects but also are sensitive to jamming signals with particular frequency relations to the animal's own EOD.