Biomedical subjects
M Rezak
Publications and source records attributed to M Rezak.
A comparison of the organization of the projections of the dorsal lateral geniculate nucleus, the inferior pulvinar and adjacent lateral pulvinar to primary visual cortex (area 17) in the macaque monkey.
Both anterograde and retrograde transport tracing methods were used to study the organization of the projections of the dorsal lateral geniculate (DLG), the inferior pulvinar and subdivisions of the lateral pulvinar to primary visual cortex (striate cortex or area 17). The DLG projects only to striate cortex. These projections are retinotopically organized, and do not extend to any cortical layers above layer IVA. In contrast the inferior pulvinar (PI) and the immediately adjacent portion of the lateral pulvinar (PL alpha 48) project to both striate and prestriate cortex. The projections from these two thalamic areas to the striate cortex are also retinotopically organized and exist in parallel with those from the DLG. In contrast to the DLG, the projections from PI and PL alpha terminate above layer IVA in striate cortex, i.e. layers I, II and III. In prestriate cortex the layers of termination include layers IV, III and I. The pulvinar terminations in layers II and III of area 17 occur in segregated patches as do the geniculate terminations in layers IVC and IVA. On the other hand the pulvinar terminations in layer I which overlie those in layers II and III of area 17 appeared to be continuous. Control studies show that the remainder of the lateral pulvinar overlying PL alpha does not project to striate cortex. It is concluded that there are 3 visuotopically organized inputs from the lateral thalamus to primary visual cortex and that each of these inputs have different layers of termination. The inputs from PI and DLG can convey direct retinal inputs while those from PI and PL alpha can also be involved in intrinsic cortico-thalamocortical connection with prestriate cortex. It remains, then that it cannot be tacitly assumed that the ascending inputs which influence the response properties of the primary cortical neurons arise solely from the dorsal lateral geniculate nucleus. It is also argued that these inputs to the supragranular layers may be excitatory as those from the DLG to the IVth layer.
Some observations on the patterns of segregated geniculate inputs to the visual cortex in New World primates: an autoradiographic study.
Explore the source record for details and available documents.
An autoradiographic study of the projections of the pretectum in the rhesus monkey (Macaca mulatta): evidence for sensorimotor links to the thalamus and oculomotor nuclei.
Autordiographic tracing methods were used to determine the differential projections of the pretectal nuclei, in the rhesus monkey, in relation to their inputs. The sublentiform (SL) and olivary (ON) nuclei receive projections from the visual cortex, superior colliculus (SC) and equal bilateral projection from the retina. The nucleus of the posterior commissure (NPC) and its subdivisions do not receive any of these inputs. The projections of the pretectum involve a number of structures within the thalamus and brain stem and there are differences in the projection targets of the pretectal region which receives direct visual input (i.e., SL and ON) and the region which does not (i.e., nucleus of the posterior commissure, NPC). For example, while all pretectal regions project within the pretectum and to the SC, accessory oculomotor nuclei, reticular formation, intralaminar nuclei and hypothalamus, it is only the retinorecipient zone which projects to rostral regions such as the visceral oculomotor nuclei, the lateral pulvinar, the border between the lateral pulvinar and medial pulvinar, the oral pulvinar as well as to the thalamic reticular nucleus, ventral lateral geniculate nucleus, zona incerta and other structures. It is concluded that the retina, SC and cortex which influence the visceral oculomotor nuclei can only do so by virtue of their projections to the pretectum, and that any consideration of accommodative and pupillary reflexes must view the pretectum as an obligatory link through which various structures can influence the intrinsic musculature of the eye. In contrast to the SC, the pretectum does not project to any of the visual relay nuclei of the thalamus, such as the inferior pulvinar, which project to the visual cortices. Instead, the pretectum projects directly to visuomotor, visceromotor and arousal systems.
Auditory--visual interaction in single cells in the cortex of the superior temporal sulcus and the orbital frontal cortex of the macaque monkey.
Explore the source record for details and available documents.
The cortical projections of the inferior pulvinar and adjacent lateral pulvinar in the rhesus monkey (Macaca mulatta): an autoradiographic study.
An autoradiographic technique was used to determine superior colliculus (SC) and pulvinar projections in the rhesus monkey. SC projects bilaterally to the inferior pulvinar (PI) while occipital cortex projects to PI and the lateral pulvinar (PL). PI has sustaining, topographical projections to layers IV, III and I of areas 18 and 19 (and VI and I of 17) which agrees with the central representation of the visual hemifield and suggests that there is more than one hemifield representation in prestriate cortex. PL adjacent to PI also projects to the same cortical areas and layers, while the portion of PL extending into the caudal pole of the pulvinar projects to layers IV, III and I of areas 20 and 21. Thus, occipital cortices are associated by cortico-thalamocortical connections and also receive direct lemniscal input via SC-PI and the dorsal lateral geniculate nucleus (DLG), while inferotemporal areas 20 and 21 receive only cortico-thalamocortical connections. It is concluded that Stoffels' principle of lamellation holds and, that one pulvinar subdivision projects to several cortical areas, that adjacent pulvinar subdivisions have overlapping projections to these cortical areas and their layers and that the pulvinar also projects to the same cortical area as DLG but to different layers. These connections are similar to those in lower mammals but not to those in the squirrel monkey and bushbaby.
Extrageniculate projections to layers VI and I of striate cortex (area 17) in the rhesus monkey (Macaca mulatta).
Explore the source record for details and available documents.