EFFECTS OF NEONATAL WHISKER LESIONS ON MOUSE CENTRAL TRIGEMINAL PATHWAYS
EFFECTS OF NEONATAL WHISKER LESIONS ON MOUSE CENTRAL TRIGEMINAL PATHWAYS
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DOI：
10.1002/cne.902230308
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发表时间：
1984-01-01
影响因子：
2.5
通讯作者：
WOOLSEY, TA
中科院分区：
文献类型：
--
作者：
DURHAM, D;WOOLSEY, TA
在啮齿类动物的中枢神经系统中，面部的纤维须或胡须有很大的代表性。在大鼠和小鼠中，从每个触须产生的投射可以在中央三叉神经通路的5个独立部分中进行组织学证明。在每个位置，突起的图案与面部触须的图案同构。在躯体感觉皮层（SmI），多细胞cytoarchitectonic单位在第四层-称为桶-对应的解剖和功能对侧的胡须。皮质桶在出生时缺席，其cytoarchitectonic模式可以改变新生儿胡须病变。这种影响是分级的，使得出生后第6天（PND）或之后的胡须损伤不会产生解剖学躯体解剖学的变化。确定了小鼠皮层下三叉神经站中存在对触须损伤敏感性的类似临界期。皮质下投射是否易受与其他发育序列相似的晶须损伤的影响，或者关键期与发育的其他方面有关？新生Swiss韦伯斯特小鼠在PND 1、2、3、4或5时出现单排胡须病变。这些动物能活到成年。他们的大脑切片和染色的线粒体酶，琥珀酸脱氢酶（SDH），这表明在所有的中枢神经系统站的晶须体貌。在每个层次的途径，往往在同一个人的胡须表示，重建连续切片，以评估定性和定量的变化，躯体。通过实验动物的面部组织切片被用来确定胡须损伤的程度，并显示出很少的神经纤维支配面部的损伤区。在脑干表征中，与受损胡须相对应的区域萎缩和苍白，无论动物在触须损伤时的年龄如何;这可能反映了初级传入神经的退化。在丘脑和皮质，晶须损伤在出生后的时间逐渐减少对解剖预测模式的影响。基于与受损触须相关的投影模式的变化和与剩余的完整触须相关的投影模式的变化，每个中央触须表示具有时间上不同的临界期。关键期首先在脑干结束，其次在丘脑，最后在皮层。一个外围到中央的顺序，在发展中的躯体定位模式的途径，这样一个给定的站可能会指示下一个更中央的。两个支持证据是神经元在通路中产生的顺序和通路的每个部分分化为成人形态的顺序;两者都有类似的由外向内的顺序。
The mystacial fibrissae or whiskers on the face have a large representation in the rodent CNS. In rats and mice the projections arising from each vibrissa can be demonstrated histologically in 5 separate parts of the central trigeminal pathway. At every location, the pattern of the projections is isomorphic to the pattern of the facial vibrissae. In the somatosensory cortex (SmI), multicellular cytoarchitectonic units in layer IV-termed barrels-correspond anatomically and functionally to the contralateral whiskers. The cortical barrels are absent at birth and their cytoarchitectonic pattern can be altered by neonatal whisker lesions. The effect is graded such that whisker damage on or after postnatal day (PND) 6 does not produce changes in the anatomical somatotopy. Similar critical periods existence for susceptibility to vibrissa damage in the subcortical trigeminal stations of mice was determined. Are subcortical projections susceptible to whisker damage in a sequence which parallels other described developmental sequences, or are the critical periods related to other aspects of development? Neonatal Swiss Webster mice sustained lesions of a single row of whiskers on PND 1, 2, 3, 4, or 5. The animals survived to adulthood. Their brains were sectioned and stained for the mitochondrial enzyme, succinic dehydrogenase (SDH), which demonstrates whisker somatotopy in all CNS stations. The whisker representations at each level of the pathway, often in the same individual, were reconstructed from serial sections to assess qualitative and quantitative changes in somatotopy. Histological sections through the faces of the experimental animals were used to determine the extent of whisker damage and to show that few nerve fibers innervate the damaged zone on the face. In the brainstem representations, the zones corresponding to the damaged whiskers are shrunken and pale, regardless of the animal''s age at vibrissia damage; this probably reflects the degeneration of the primary afferents. In the thalamus and the cortex, whisker damage at later postnatal times has progressively less effect on the anatomical projections patterns. Based on the changes in the projection patterns related to the damaged vibrissae and the changes in the projection patterns related to the remaining, intact vibrissae, each central vibrissal representation has a temporally different critical period. The critical period ends 1st in the brainstem, next in the thalamus and last in the cortex. A peripheral-to-central sequence in the development of somatotopic patterns in the pathway, such that a given station might instruct the next more central one. Two supporting lines of evidence are the order in which neurons in the pathway are generated and the order in which each part of the pathway differentiates to an adult morphology; both have a similar outside-to-in sequence.