EARLY POST-NATAL DEVELOPMENT OF NEURONAL FUNCTION IN THE KITTENS VISUAL-CORTEX - A LAMINAR ANALYSIS
EARLY POST-NATAL DEVELOPMENT OF NEURONAL FUNCTION IN THE KITTENS VISUAL-CORTEX - A LAMINAR ANALYSIS
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DOI：
10.1113/jphysiol.1984.sp015104
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发表时间：
1984-01-01
影响因子：
5.5
通讯作者：
WOLF, W
中科院分区：
文献类型：
--
作者：
ALBUS, K;WOLF, W
本研究通过对麻醉和麻痹幼猫（6 ~ 24日龄）纹状体和纹旁皮质612个单个神经元的细胞外记录，研究了视皮质功能的正常生后发育。分析了感受野特性（如方向特异性和开区与关区的空间组织）的发展趋势的层间差异。在出生后第2周开始时，大多数神经元（76%）仅对光关闭（单峰关闭神经元）有反应。只有在以后才出现单峰神经元和双峰或多峰神经元的频率（具有并排布置的空间上分离的开和关区域）增加，使得在第4周的中间，这三种感受野类型的数量大致相等，开关型神经元的比例（具有空间上一致的开和关区域）在产后早期保持较低（在9%和12%之间）。在第17和18区的第4和第6层，即使在最年幼的小猫中，视觉神经元的出现频率也是相当正常的，而在小于14日龄的小猫中，在第2/3和第5层中记录神经元的概率非常低，直到第4周的中期才逐渐提高。即使在非常年轻的小猫观察到定向特异性神经元和眼优势分布的空间排列的一个基本顺序。这一顺序迅速提高，并在出生后第4周达到成人水平。在视觉经验不足的小猫中，平均11%的反应神经元对细长视觉刺激的方向有选择性，58%有偏见。方向选择细胞的比例在开盖后2天左右开始迅速增加，到生后4周末达到与成人相似的比例。在小于10日龄的幼猫中，方向选择性神经元仅存在于第4层和第6层以及第3层的下部。在第2/3和5层，它们首先在出生后第3周开始时以较大的比例出现。在出生后第1个月，视皮层神经元功能发育的时间进程取决于感受野类型和皮层内位置。皮质内连接的发展和简单的感受野的产生的影响进行了讨论。可能的机制，和功能的影响，晚一代的复杂领域的建议。
The normal postnatal development of visual cortical functions was studied by recording extracellularly from 612 single neurons in the striate and parastriate cortex of anesthetized and paralyzed kittens (6 to 24 days old). Analyses were made of laminar differences in the developmental trends of receptive field properties such as orientation specificity and spatial organization of on and off zones. At the beginning of the 2nd postnatal wk the majority of neurons (76%) only respond to light off (unimodal off neurons). Only later does the frequency of occurrence of unimodal on neurons and of bimodal or multimodal neurons (with spatially segregated on and off zones arranged side by side) increase so that, by the middle of the 4th wk, about equal numbers of these 3 receptive field types are found. The proportion of on-off neurons (with spatially coincident on and off zones) remains low (between 9% and 12%) during the early psot-natal period. In layers 4 and 6 of areas 17 and 18 the frequency of occurrence of visual neurons is qute normal even in the youngest kittens, whereas the probability of recording neurons in layers 2/3 and 5 in kittens less than 14 days old is remarkably low and only gradually improves up to the middle of the 4th wk. A rudimentary order in the spatial arrangement of orientation-specific neurons and ocular dominance distribution is observed even in very young kittens. This order improves rapidly and reaches adult levels during the 4th postnatal wk. In visually inexperienced kittens, on average 11% of all responsive neurons are selective for the orientation of elongated visual stimuli and 58% are biased. The proportion of orientation-selective cells begins to increase rapidly about 2 days after lid opening and proportions of orientation-selective cells similar to that in the adult are reached by the end of the the 4th postnatal wk. Orientation-selective neurons in kittens less than 10 days old are only found in layers 4 and 6 and the lower part of layer 3. In layers 2/3 and 5 they are first seen in larger proportions by the beginning of the 3rd postnatal wk. During the 1st postnatal mo., the time course of the functional development of visual cortical neurons depends on receptive field type and on intracortical location. Implications for the development of intracortical connectivity and the generation of simple receptive fields are discussed. Possible mechanisms for, and functional implications of the late generation of complex fields are suggested.