Diversity among Purkinje cells in the monkey cerebellum.

A monoclonal antibody (B1) produced against rat embryonic forebrain membranes shows specific and striking immunohistochemical staining of Purkinje cells in the monkey cerebellum in a pattern of broad parasagittal alternating bands of cells either possessing or lacking the B1 antigen. In addition, the neurons of the deep cerebellar nuclei and some neurons of the motor cortex and of the spinal cord also contain the B1 antigen. Neurons with the B1 antigen were also seen in the somatosensory cortex, the vestibular and cochlear nuclei, and the retina.

Alterations in visually related eye movements following left pulvinar damage in man.

This case study presents evidence for two subtle types of eye movement abnormalities following surgical resection of the left posterior pulvinar in man. First, visual fixations during vertical pattern matching are on average both increased in number and prolonged in duration compared to controls, although normal fixation durations also occur. Second, unilateral deficiencies during search and scanning performance are associated with eye movements directed into the hemifield contralateral to the lesion. Although direct damage to parietal cortex and indirect damage to other visually related structures cannot be ruled out as other explanations for these deficits, these findings are consistent with recent electrophysiological and behavioral studies of the pulvinar in both human and non-human primates, and suggests a fruitful area for further investigation of pulvinar function.

Anatomical organization of primate visual cortex area VII.

The Golgi Rapid and Kopsch techniques have been used to provide material for an examination of the internal neuronal organization of cortical area VII of the Macaca monkey. The afferent and efferent relationships of area VII, as shown by axoplasmic transport tracing techniques in our own material and in previous studies in other laboratories, are reviewed. Comparison is made between the internal organisation of VI and VII cortex in terms of (1) the marked different in spiny and nonspiny neurons populations of granular layer 4, (2) the difference in relationship of lamina 6 pyramidal neurons to the overlying layers with a shift away from any relationship to granular layer 4 in VII, and (3) differences in the organization of VI lamina 4B and VII lamina 3B--both similarly placed, fiber-rich bands in the two cortical areas. The extrinsic relationships of VI and VII with the lateral geniculate nucleus, superior colliculus, pulvinar, peristriate cortex, cortical area STS, and with each other are compared in terms of laminar locations of efferent neurons and afferent axon terminal fields. It is hoped that this anatomical survey will provide a better foundation for physiological explorations of the region.

The structural organization of the inferior and lateral subdivisions of the Macaca monkey pulvinar.

Previous light microscopic studies of Macaca pulvinar have demonstrated that both the inferior and adjacent portion of the lateral pulvinar subdivisions are reciprocally connected to the entire occipital lobe, including striate cortex. They differ in that inferior but not lateral pulvinar receives a projection from the superficial layers of the superior colliculus. In this study, the internal organization of these two subdivisions in compared by relating light microscopic Golgi morphology to the synaptic organization observed by electron microscopy. The Golgi impregnated neurons in inferior and lateral pulvinar are typical of other thalamic nuclei and are not qualitatively different in the two subdivisions. Projections neurons (PN) vary in cell body (15--40 micrometers) and dendritic tree (150--600 micrometers) diameters but bear the same varieties of dendritic appendages; spine-like, hair-like, and knot-like. Local circuit neurons (LCN) have smaller cell body diameters (10--20 micrometers) but can have very large dendritic field diameters (150--600 micrometers). They are best distinguished from PNs by their elaborate dendritic appendages, which have been identified as pre-synaptic dendrites in the EM. LCN axons are infrequently seen. In the EM both subdivisions contain four types of synaptic terminals. RS and RL terminal both contain round symaptic vesicles and make asymmetric synaptic contacts, but are subdivided on the basis of small (RS = 0.09 micrometers) versus large (RL = 2.2 micrometers) cross sectional diameters and organelle content. RLs contact larger caliber dendrites and frequently form synaptic complexes with presynaptic dendrites of LCNs, while RSs contact fine caliber dendrites and rarely take part in synaptic complexes. F terminal and P boutons both contain flat and pleomorphis vesicles and make symmetric synaptic contacts. They are characterized by vesicle number and cytoplasmic density. Fs are infrequently observed in pulvinar compared to P boutons and are of uncertain origin. P boutons can be equated with LCN dendritic appendages and have been identified as pre-synaptic dendrites. The quantitative distribution of each type is very similar in both subdivisions, avveraging RS 85%, RL 5%, F 0.3%, P 8% and unidentified 2%.

The morphology and distribution of striate cortex terminals in the inferior and lateral subdivisions of the Macaca monkey pulvinar.

The origin of the various types of axon terminals in Macaca pulvinar remains uncertain because of the contradictory results obtained in EM degeneration studies. We have used EM-autoradiography to determine the morphology of terminals in the inferior and lateral pulvinar which originate from neurons in visual cortex. After injections of H3 proline into area 17, both the small diameter (RS) and the large diameter (RL) terminals containing round vesicles and making asymmetric contacts are labeled in the two pulvinar subdivisions. Labeled and unlabeled terminals are intermixed within the pulvinar focus which suggests that the dendrites of the same pulvinar neuron receive overlapping inputs from several cortical areas. Because only 5% of the pulvinar terminals are RLs (Ogren and Hendrickson, '79), and this small number of RLs originates from at least two visual cortical areas plus the superior colliculus (Partlow et al., '77), superior colliculus input to inferior pulvinar is small compared to the combined RS and RL cortical input. Together the findings from this study and the preceding paper (Ogren and Henderickson, '79), show that while pulvinar is typical of other thalamic nuclei in the structure of its neurons and synapses, it differs in that the input from subcortical structures is minimal. It is suggested that inferior and lateral pulvinar function principally as integrators of visula cortical information.

The neuroanatomical organization of pathways between the dorsal lateral geniculate nucleus and visual cortex in Old World and New World primates.

Pathways between the dorsal lateral geniculate nucleus (dLGN) and visual cortex in Old World (Macaca, Papio, Erythrocebus, Cercopithecus) and New World (Saimiri, Cebus) primates were studied after injections of horseradish peroxidase and H3 or S35 amino acids into the dLGN or visual cortex. Trans-synaptic autoradiography was also used to study these pathways after an injection of H3 proline-fucose into one eye. The subsequent autoradiographs of visual cortex showed that Old World primates have separate eye inputs (ocular dominance columns) in the striate cortex, whereas New World monkeys have overlapping or non-separated eye inputs. In both primate groups the geniculocortical input to layer IVA formed a pattern which resembled a honeycomb in tangential sections, unlike the solidly labeled layer IVC. Also common to the two primate groups was a projection from dLGN to layer VI. There was no dLGN projection to any prestriate area in any of the primates. However, after an injection limited to the prestriate cortex of Macaca, light autoradiographic labeling was seen in the interlaminar zones and the magnocellular and S laminae, demonstrating a prestriate-dLGN pathway. Our results indicate that the primate visual system differs significantly from the cat in having no dLGN projection to area 18. There are also signficant differences between primates in the level at which the possibility of binocularity (of an excitatory nature) first occurs in the striate cortex because in the species studied thus far with neuroanatomical methods, Old World primates have ocular dominance columns in layer IV but most New World monkeys lack them.