Cytochrome oxidase in the human visual cortex: Distribution in the developing and the adult brain

Abstract

Cytochrome-oxidase (CO) histochemistry has revealed important functional subdivisions, modules, and processing streams in the macaque visual cortex. The present study is aimed at analyzing the development and characteristics of CO patterns in the human visual cortex by means of histochemistry and immunohistochemistry. At 26 weeks of gestation, both the ventricular and subventricular zones had low levels of CO, while the cortical plate had moderate levels of CO. At birth, supragranular CO-rich zones (puffs) were not clearly organized, indicating that the development of puffs in the neonatal striate cortex lags behind that of the macaque monkey, whose puffs appear weeks before birth. Puffs were more clearly discernible in human cortex at postnatal day 24, and became well organized by the fourth postnatal month. Layer IVc a in the neonate exhibited a higher level of activity and amount of CO than the central portion of IVc^, which contained a dense aggregate of small neurons. The base of IVc^, however, was often as CO reactive as IVc a . In contrast, the majority of specimens available to us from the fourth postnatal month and from adults with no known neurological diseases had significantly greater CO reactivity in layer IVc^ than in IVc a . Layer VI was moderately reactive for CO throughout development. In V2, stripes with globular zones of high CO activity were sporadically present at birth, suggesting that their development may parallel or precede that of puffs in VI. These stripes with CO-rich globular zones became more prominent in the adult and radiated orthogonally from the V1/V2 border. They were not, however, clearly organized into alternating thick and thin stripes as they are in the squirrel monkey. Visual cortical areas beyond V2 exhibited high CO activity mainly in layers III and IV and moderate levels in VI, suggesting that sites associated with cortico-cortical pathways may be metabolically most active.

Distinctive compartmental organization of human primary visual cortex

“…Our results confirm previous reports that the CO staining pattern of humans differs from that of most monkeys (17,(25)(26)(27)(28) and indicate that at least some apes, specifically, chimpanzees and probably also orangutans, possess a humanlike condition. The ape-human pattern is marked by the absence of the thin, dense band of CO staining within layer 4A that is typical of nonhominoids, along with darker staining of layer 4B than is seen in monkeys.…”

“…The fact that the honeycomb is so common in New World and Old World monkeys suggests it should be present in hominoid primates (apes and humans), animals that are closely related to Old World monkeys (24). It is thus surprising that published studies are unanimous in reporting that humans lack a CO-dense 4A band (17,(25)(26)(27)(28). This finding has led WongRiley et al (28) to suggest that the organization of the geniculate projection to layer 4A may have been modified in humans compared with monkeys.…”

“…It is thus surprising that published studies are unanimous in reporting that humans lack a CO-dense 4A band (17,(25)(26)(27)(28). This finding has led WongRiley et al (28) to suggest that the organization of the geniculate projection to layer 4A may have been modified in humans compared with monkeys. However, Wong-Riley (28) also raises the possibility that the difference in CO staining is an artifact of relatively poor tissue preservation in humans compared with monkeys: Experimental monkey tissue is typically fixed by perfusion at the time of death whereas in humans, brains are removed several hours after death and are fixed by immersion in aldehydes, and the delay could result in loss of CO activity.…”

Development of Connections in the Human Visual System During Fetal Mid-Gestation: A Dil-Tracing Study

“…3F). Previous studies have shown that the deep portion of the marginal zone also contains abundant synapses (24) and is rich in cytochrome oxidase (19), a metabolic marker of neuronal functional activity (29).…”

“…Second, there is a rich context of previous studies on the development of visual pathways in animals, including primates (6)(7)(8)(9)(10)(11), providing a basis for comparative analysis. Third, previous studies have described the histological development of the human lateral geniculate nucleus (LGN) (4,(12)(13)(14)(15)(16)(17) and visual cortex (4,11,18,19) in detail. Fourth, the anatomical components of the visual system (i.e.…”