摘要:

Thalamic projections to parietal regions of cerebral cortex were investigated in the cat by retrograde degeneration and retrograde transport techniques. Studies of retrograde cellular changes indicate cortically projecting cells in the lateroposterior nucleus (LP), rostral pulvinar (Pul), and the ventral part of the laterodorsal nucleus (LD). When lesions were placed in the cortex of young kittens, clear chromatolytic changes and cell loss were also consistently observed in middle and caudal parts of the ventroanterior nucleus (VA). Investigations of retrograde transport following intracortical injections of horseradish peroxidase have confirmed the results of retrograde degeneration studies by demonstrating cortically projecting cells in VA, LP, LD, and Pul. Retrograde transport studies also indicate cortically projecting cells in the central lateral nucleus. Material from both experimental techniques demonstrates a loose topographic organization of the projections from the lateral thalamus. Anterior parts of LP project to the anterior lateral gyrus and anterior middle suprasylvian gyrus. Middle LP and rostral Pul project to the middle suprasylvian gyrus.

ISSN:0006-8977    

DOI:10.1159/000125659

出版商:S. Karger AG    

年代:1977

数据来源: Karger

摘要:

Many schemes of ganglion cell classification seek to classify the cells by some particular characteristic, such as the time course of the cells'' physiological responses or their dendritic morphology. It is here argued that such schemes are based on the Aristotelian concept of ''essences'' and raise the same difficulties as have arisen with the essentialist approach to animal taxonomy. A better approach to the classification of neurones, it is proposed, is to base the classification on as many features of the cells as possible, and to regard the classification as an hypothesis, subject to testing and modification by experience, about the ''functional niches'' occupied by the cell types distinguished.

ISSN:0006-8977    

DOI:10.1159/000125660

出版商:S. Karger AG    

年代:1977

数据来源: Karger

摘要:

Many schemes of ganglion cell classification seek to classify the cells by some particular characteristic, such as the time course of the cells'' physiological responses or their dendritic morphology. It is here argued that such schemes are based on the Aristotelian concept of ''essences'' and raise the same difficulties as have arisen with the essentialist approach to animal taxonomy. A better approach to the classification of neurones, it is proposed, is to base the classification on as many features of the cells as possible, and to regard the classification as an hypothesis, subject to testing and modification by experience, about the ''functional niches'' occupied by the cell types distinguished.

ISSN:0006-8977    

DOI:10.1159/000125661

出版商:S. Karger AG    

年代:1977

数据来源: Karger

摘要:

The influence of the visual wulst on the optic tectum of Columba livia were studied. Analysis of the surface field potential evoked by optic nerve stimulation showed that it is composed of two presynaptic waves (pr1 and pr2), a negative monosynaptic wave (N) and a late, positive component (P) due to activation of deeply located neurons. Single shock visual wulst stimulation elicited a surface-positive field potential the depth profile of which showed that it is due to the activation of neurons of the deep tectal layers, probably different from those responsible for the P wave. Visual wulst stimulation depresses the positive component of the field potential elicited by optic nerve stimulation. It is suggested that this effect is mediated by intratectal inhibitory interneurons.

ISSN:0006-8977    

DOI:10.1159/000125662

出版商:S. Karger AG    

年代:1977

数据来源: Karger

ISSN:0006-8977    

DOI:10.1159/000125658

出版商:S. Karger AG    

年代:1977

数据来源: Karger