LEI Code, Legal Name, City, Ctry GENEVA. CH. BETVBDK FREDERICK CHARLES SEYMOUR NINNIM DECEASED. FAREHAM. GB. SIGN IN. YOUR ACCOUNT. Username. Main Details. Status and Registration. Other Names. Other Addresses. Associated LEIs. Related LEIs. Error Reporting. X.M. He and T. Baumgartner, RSC Adv., 3, e (). T. Lei, J.Y. Wang, and J. Pei, Acc. Chem. Res., 47, e (). A. Patra, M. Bendikov .
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Sensory input from the whiskers is the major component, but not all, of primary sensory information conducted by ION, and this may account for shorter time window for the lesion of whisker hair follicles in affecting callosal projection relative to that for ION transection. Similar results were obtained by lesion of whisker hair follicles.
In this study, we removed somatosensory input by transecting the ION or lesion of whisker hair follicles to examine the effects of sensory input on the development of the corpus callosum. On the other hand, accumulated evidence indicates that neuronal activity is critical in lwi pathfinding. Received Nov 24; Accepted Nov Normal patterns of spontaneous activity are required for correct motor axon guidance and the expression of specific guidance molecules.
Sensory input is required for callosal axon targeting in the somatosensory cortex
Lesi, bilateral lesion of whisker hair follicles; Cont, contralateral side; Kei, ipsilateral side; Uni. To test this possibility, c-Fos was used to examine cortical neuronal activity in P9 brain slices prepared from mice with P5 unilateral or simultaneous bilateral removal of sensory input.
Competing interests The authors declare that they have no competing interests. This article has been cited by other articles in PMC.
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Journal List Mol Brain v. As development progressed, ION transection had progressively less effect. YQD conceived the study.
Ventral posteriomedial thalamic nucleus; Uni. Electric pulses were then delivered to the embryos by gently clasping their heads with forceps-shaped electrodes connected to a square-pulse generator, ECM BTX; Holliston, MA. Whole-cell patch-clamp recordings were performed after the brain slices at a proximate level of Bregma Callosal projection, Sensory input, Axon pathfinding, Somatosensory cortex. Abstract Background Sensory input is generally thought to be necessary for refining and consolidating neuronal connections during brain development.
Having found that sensory input to both callosal neurons and their targeting cortex is required for callosal axon target selection, we were prompted to explore the effects of eliminating sensory input altogether.
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It is well accepted that prior to initial contact formation, intrinsic developmental programs and external guidance cues are responsible for guiding growing axons into their target field [ 20 – 23 ], and sensory input is required 113334 refining and consolidating neuronal connections in developing neuronal networks [ 2425 ].
Comparison of numbers of c-Fos-positive neurons is shown in G ; animal numbers examined are indicated. Transection at P5, however, does not disrupt barrel formation [ 1617 ], but would be expected to eliminate the later sensory input.
Strikingly, blocking sensory input bilaterally, by simultaneously transecting both IONs, results in rescued callosal projection. Every sixth sections were collected as one set section, in which about three sections were included at the approximate level of Bregma We pursued this further by assessing the effects of non-simultaneous bilateral ION transection.
Our data demonstrate a critical role of balanced leu somatosensory input in the formation of callosal connections, and thus reveal a new role of sensory input in wiring brain circuits. In mouse, the early-born layer V callosal neurons cross the midline before birth, while the late-born layer II-III callosal neurons cross the midline several days after birth [ 3 – 5 ]. Published online Dec 5.
Thus, it might be possible that callosal neurons in both somatosensory and visual cortices require matched bilateral sensory input to form their callosal connections. Callosal projection is affected by unilateral but rescued by bilateral lesion of whisker hair follicles. To examine electrophysiological changes of cortical neuron after unilateral or bilateral removal of sensory input, patch-clump recording was performed in brain slice.
Besides, the neuronal activity is altered in the somatosensory cortex after removal of sensory input. Unilateral or non-simultaneous bilateral removal of sensory input may disrupt the balance of bilateral sensory input to the two somatosensory cortices, which may in turn lead to mismatched activity between the two cortices. Our results demonstrate that synchronous bilateral sensory input is required for target selection of callosal neurons at system level.
Mutation of the Emx-1homeobox gene disrupts the corpus callosum. All authors read and approved the final manuscript. In contrast, unilateral lesion of the optic tract, which lfi all visual input to one lej, results in a nearly complete absence of callosal connections in the border region between the primary and secondary visual cortices [ 19 ].
Failure of callosal innervation is detected at P8, and still present in adulthood. However, it should be noted that our neurophysiological results are not sufficient to establish a causal link between the mismatched neuronal activity and defective callosal projection, and further studies are needed to explore this question. Neuronal activity is altered in the somatosensory cortex after removal of sensory input.
In this study, we found that unilateral transection of ION during early postnatal period arrested callosal projection lek the contralateral cortex. To follow the outgrowth of callosal axons of somatosensory neurons, we delivered an EGFP expression construct into the pyramidal neurons of the somatosensory cortex by in utero electroporation at Hair follicles of whiskers were destroyed by a heated thin wire at P4-P7 and callosal projections were examined at P Results Eliminating sensory input to either hemisphere by unilateral transection of infraorbital nerve ION prevents target selection of callosal axons in contralateral cortex.