Funahashi M, Stewart M
Department of Physiology, State University of New York Health Science Center at Brooklyn 11203, USA.
Hippocampus. 1997;7(2):117-29. doi: 10.1002/(SICI)1098-1063(1997)7:2<117::AID-HIPO1>3.0.CO;2-K.
Intracellular recordings and Neurobiotin-injection were used to examine the electrophysiology and morphology of presubicular and parasubicular cortical neurons in horizontal slices from rat brains. Evoked responses were obtained by stimulation of subicular and entorhinal cortices. Stellate cells were recorded in layers II and V of presubiculum and parasubiculum. Superficial layer cells had spiny dendrites that were found to reach layer I. Deep layer cells had sparsely spiny dendrites or dendrites without spines that did not reach past layer IV. Pyramidal cells were recorded in layers III and V of presubiculum and layers II and V of parasubiculum. Superficial layer cells had spiny dendrites that were found to reach layer I. Deep layer cells had sparsely spiny dendrites or dendrites without spines that could reach layer II. Electrophysiologically, stellate and pyramidal cells were similar to one another, regardless of cell layer, exhibiting repetitive single spiking in response to depolarizing current injection. No cells were found to burst in response to current injection. While there were subtle electrophysiological differences among the cell types, stellate cells were more similar to pyramidal cells from the same or adjacent layers than to other stellate cells from more distant layers. Similarly, pyramidal cells were electrophysiologically more similar to nearby stellate cells than to other distant pyramidal cells. Cells of all layers responded to subicular stimulation with a short latency (< 9 ms), excitatory postsynaptic potential. Superficial layer cells responded at short (< 9 ms), longer (10-20 ms) and very long latencies (> 20 ms) to stimulation of superficial layers of medial entorhinal cortex. Deep layer cells responded at short latencies (< 9 ms) to stimulation of deep layers of medial entorhinal cortex. Many cells responded to both subicular and entorhinal inputs. Both pyramidal and stellate cells in the deep layer of pre/parasubiculum could exhibit population bursting behavior in response to stimulation of subiculum or entorhinal cortex. The results define the cellular morphology and basic electrophysiology of presubicular and parasubicular neurons of the rat brain as a step toward understanding the physiology of the retrohippocampal cortices.
采用细胞内记录和神经生物素注射技术，研究大鼠脑水平切片中前下托和下托旁皮质神经元的电生理学和形态学。通过刺激下托和内嗅皮质获得诱发反应。在前下托和下托旁的II层和V层记录到星形细胞。浅层细胞有棘状树突，延伸至I层。深层细胞有稀疏的棘状树突或无棘树突，未超过IV层。在前下托的III层和V层以及下托旁的II层和V层记录到锥体细胞。浅层细胞有棘状树突，延伸至I层。深层细胞有稀疏的棘状树突或无棘树突，可延伸至II层。电生理学上，星形细胞和锥体细胞彼此相似，无论细胞层如何，对去极化电流注射均表现出重复单峰发放。未发现细胞因电流注射而爆发。虽然细胞类型之间存在细微的电生理差异，但星形细胞与来自相同或相邻层的锥体细胞比与来自更远层的其他星形细胞更相似。同样，锥体细胞在电生理上与附近的星形细胞比与其他远处的锥体细胞更相似。所有层的细胞对下托刺激均产生短潜伏期（<9毫秒）的兴奋性突触后电位。浅层细胞对内侧内嗅皮质浅层刺激产生短（<9毫秒）、长（10 - 20毫秒）和非常长潜伏期（>20毫秒）的反应。深层细胞对内侧内嗅皮质深层刺激产生短潜伏期（<9毫秒）的反应。许多细胞对下托和内嗅输入均有反应。前下托/下托旁深层的锥体细胞和星形细胞对下托或内嗅皮质刺激均可表现出群体爆发行为。这些结果确定了大鼠脑前下托和下托旁神经元的细胞形态和基本电生理学，是迈向理解海马后皮质生理学的一步。
