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Neurotransmitters in the human nervous system
Source: 1995;43(1-24).
Author: Paxinos G, Sexton PM, Toga AW.
Abstract:
The use of chemoarchitecture for identification of nuclei in the human brain is significant because the connectivity criterion is virtually impossible to apply. Other anatomical criteria that have been used for experimental animals are also more difficult to use in the human, leaving chemoarchitecture as an important choice for this species. Fortunately, a striking resemblance in the neurotransmitter or neuromodulator content of nuclei has been observed across species. Chemoarchitecture has been used successfully and can be as valid a criterion in identifying regions as connectivity and cell morphology, the more conventional criteria. While differences in distribution of substances can exist between species and indeed there may be differences even amongst strains of the same species, the overwhelming impression is that the chemoarchitectonic profile of nuclei is substantially stable across species. As a consequence, once the chemoarchitectonic signature of a nucleus has been identified in an experimental species, the nucleus in the human brain bearing the same profile of chemicals is expected to be the human homologue. Each chemical substance offers a different window to the organization of the brain, with successive stain betraying autoradiographic/immunohistochemical reaction has been performed, all nuclei/subnuclei will be revealed. Chemoarchitecture provides a view of the brain which is similar to a neuroanatomical map which has been coloured in already. While the distribution of any one substance may show flagrant disregard to important boundaries, the Gestalt of the distribution of all substances under investigation will render the detail and overall plan discernible. In the present chapter, we will present examples of the use of chemoarchitecture in the delineation of three different areas of the brain. We will commence with a description of the identification of the intermediate reticular zone because this is the first area in which we applied chemoarchitecture systematically. We will proceed with a detailed discussion of the organisational plan of the periaqueductal grey, an area in which we are currently working. Finally, we will present some evidence for the importance of the cytoarchitectonic criterion in delineations of cortical regions in the monkey, work which we have just commenced, and which has important implications for the study of the human brain.
Source: 1995;43(1-24).
Author: Paxinos G, Sexton PM, Toga AW.
Abstract:
The use of chemoarchitecture for identification of nuclei in the human brain is significant because the connectivity criterion is virtually impossible to apply. Other anatomical criteria that have been used for experimental animals are also more difficult to use in the human, leaving chemoarchitecture as an important choice for this species. Fortunately, a striking resemblance in the neurotransmitter or neuromodulator content of nuclei has been observed across species. Chemoarchitecture has been used successfully and can be as valid a criterion in identifying regions as connectivity and cell morphology, the more conventional criteria. While differences in distribution of substances can exist between species and indeed there may be differences even amongst strains of the same species, the overwhelming impression is that the chemoarchitectonic profile of nuclei is substantially stable across species. As a consequence, once the chemoarchitectonic signature of a nucleus has been identified in an experimental species, the nucleus in the human brain bearing the same profile of chemicals is expected to be the human homologue. Each chemical substance offers a different window to the organization of the brain, with successive stain betraying autoradiographic/immunohistochemical reaction has been performed, all nuclei/subnuclei will be revealed. Chemoarchitecture provides a view of the brain which is similar to a neuroanatomical map which has been coloured in already. While the distribution of any one substance may show flagrant disregard to important boundaries, the Gestalt of the distribution of all substances under investigation will render the detail and overall plan discernible. In the present chapter, we will present examples of the use of chemoarchitecture in the delineation of three different areas of the brain. We will commence with a description of the identification of the intermediate reticular zone because this is the first area in which we applied chemoarchitecture systematically. We will proceed with a detailed discussion of the organisational plan of the periaqueductal grey, an area in which we are currently working. Finally, we will present some evidence for the importance of the cytoarchitectonic criterion in delineations of cortical regions in the monkey, work which we have just commenced, and which has important implications for the study of the human brain.