Response properties and synaptic connections of mechanoafferent neurons in cerebral ganglion of Aplysia.
Response properties and synaptic connections of mechanoafferent neurons in cerebral ganglion of Aplysia.
复制标题
海兔脑神经节机械传入神经元的反应特性和突触连接。
DOI：
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发表时间：
1979
影响因子：
2.5
通讯作者：
I. Kupfermann
中科院分区：
文献类型：
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作者：
S. Rosen;K. Weiss;I. Kupfermann
1. 在头部皮肤施加触觉刺激后，发现在每个半脑神经节腹侧表面的两个小神经元簇的细胞表现出动作电位。这些神经元似乎是机械感觉传入神经，因为它们在支配皮肤的神经中具有轴突，而触觉刺激唤起没有前电位的尖峰，即使细胞体足够极化以阻止某些尖峰。机械感觉传入可能是初级传入，因为通过将神经节和外周结构浸泡在高mg2 +和低ca2 +含量的海水中，化学突触传递被阻断后，感觉反应仍然存在。2. 机械感觉传入通常是沉默的，对光、热和化学刺激不敏感。一个点状的触觉刺激施加在皮肤的限定区域，可以引起刺突的爆发。如果刺激保持恒定的力，机械感觉反应会在几秒钟内缓慢适应。重复的短暂刺激对脉冲内的尖峰频率影响很小或没有影响。3. 大约81%的机械传入神经元具有单一的同侧感受野。磁场位于嘴唇、前触手、头的背部、颈部或口周区。因为许多细胞在大脑连接体中有侧轴突，所以身体其他部位的接受野也有可能。最高的接受场密度与嘴唇有关。在每个区域内，感受野的大小和形状各不相同。相邻的字段重叠，较大的字段经常包含几个较小的字段。某些领域的特征从一种动物到另一种动物似乎是不变的。观察到机械传入细胞的地形组织形式松散。例如，位于内侧细胞簇的细胞具有唇形感受野，而位于外侧细胞簇后外侧部分的大多数细胞具有触手状感受野。4. 单个机械传入事件的细胞内刺激在假定的运动神经元中唤起短而恒定的潜伏期epsp，包括大脑神经节中已确定的b细胞簇。在几个标准的基础上，这些epsp似乎是几个标准，这些epsp似乎是化学介导的，是单突触的。5. 单个机械传入神经元的低频率细胞内重复刺激导致B簇神经元诱发的epsp振幅逐渐下降。短暂休息后，EPSP振幅可恢复，但随后的刺激会导致反应进一步减弱。6. 减弱的反应不能通过机械传入神经接受野以外的强机械刺激或脑神经或连接神经的电刺激来恢复。
1. The cells of two clusters of small neurons on the ventrocaudal surface of each hemicerebral ganglion of Aplysia were found to exhibit action potentials following tactile stimuli applied to the skin of the head. These neurons appear to be mechanosensory afferents since they possess axons in the nerves innervating the skin and tactile stimulation evokes spikes with no prepotentials, even when the cell bodies are sufficiently hyperpolarized to block some spikes. The mechanosensory afferents may be primary afferents since the sensory response persists after chemical synaptic transmission is blocked by bathing the ganglion and peripheral structures in seawater with a high-Mg2+ and low-Ca2+ content. 2. The mechanosensory afferents are normally silent and are insensitive to photic, thermal, and chemical stimuli. A punctate tactile stimulus applied to a circumscribed region of skin can evoke a burst of spikes. If the stimulus is maintained at a constant forces, the mechanosensory response slowly adapts over a period of seconds. Repeated brief stimuli have little or no effect on spike frequency within a burst. 3. Approximately 81% of the mechanoafferent neurons have a single ipsilateral receptive field. The fields are located on the lips, the anterior tentacles, the dorsal portion of the head, the neck, or the perioral zone. Because many cells have collateral axons in the cerebral connectives, receptive fields elsewhere on the body are a possibility. The highest receptive-field density was associated with the lips. Within each area, receptive fields vary in size and shape. Adjacent fields overlap and larger fields frequently encompass several smaller ones. The features of some fields appear invariant from one animal to the next. A loose form of topographic organization of the mechanoafferent cells was observed. For example, cells located in the medial cluster have lip receptive fields, and most cells in the posterolateral portion of the lateral clusters have tentacle receptive fields. 4. Intracellular stimulation of individual mechanoafferents evokes short and constant-latency EPSPs in putative motor neurons comprising the identified B-cell clusters of the cerebral ganglion. On the basis of several criteria, these EPSPs appear to be several criteria, these EPSPs appear to be chemically mediated and are monosynaptic. 5. Repetitive intracellular stimulation of individual mechanoafferent neurons at low rates results in a gradual decrement in the amplitude of the EPSPs evoked in B cluster neurons. EPSP amplitude can be restored following brief periods of rest, but subsequent stimulation leads to further diminution of the response. 6. A decremented response cannot be restored by strong mechanical stimulation outside the receptive field of the mechanoafferent or by electrical stimulation of the cerebral nerves or connectives...