Henry Kennedy

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We examined the development of the occipital lobe in fetal monkeys between embryonic day 37 (E37) and E108 in Nissl-stained and acetylcholine esterase (AChE)-reacted sections. We paid particular attention to features that distinguish the development of presumptive area 17. At E46 the neuroepithelium consists of a ventricular zone and a monolayer cortical(More)
To what extent cortical pathways show significant weight differences and whether these differences are consistent across animals (thereby comprising robust connectivity profiles) is an important and unresolved neuroanatomical issue. Here we report a quantitative retrograde tracer analysis in the cynomolgus macaque monkey of the weight consistency of the(More)
The primary visual cortex (area 17 or V1) is not thought to receive input from nonvisual extrastriate cortical areas. However, this has yet to be shown to be the case using sensitive tracers in the part of area 17 subserving the peripheral visual field. Here we show using retrograde tracers that peripheral area 17 subserving the visual field at an(More)
The directionality of corticocortical projections is classified as feedforward (going from a lower to higher hierarchical levels), feedback (interconnecting descending levels), and lateral (interconnecting equivalent levels). Directionality is determined by the combined criteria of the laminar patterns of the axon terminals as well as the cells of origins(More)
Parietal lesions in humans can produce a specific disruption of visually guided hand movement, termed optic ataxia. The fact that the deficit mainly occurs in peripheral vision suggests that reaching in foveal and extrafoveal vision rely on two different neural substrates. In the present study, we have directly tested this hypothesis by event-related fMRI(More)
The spatio-temporal timing of the last round of mitosis, followed by the migration of neuroblasts to the cortical plate leads to the formation of the six-layered cortex that is subdivided into functionally defined cortical areas. Whereas many of the cellular and molecular mechanisms have been established in rodents, there are a number of unique features(More)
Retrograde tracer injections in 29 of the 91 areas of the macaque cerebral cortex revealed 1,615 interareal pathways, a third of which have not previously been reported. A weight index (extrinsic fraction of labeled neurons [FLNe]) was determined for each area-to-area pathway. Newly found projections were weaker on average compared with the known(More)
Long-term ex vivo live imaging combined with unbiased sampling of cycling precursors shows that macaque outer subventricular zone (OSVZ) includes four distinct basal radial glial (bRG) cell morphotypes, bearing apical and/or basal processes in addition to nonpolar intermediate progenitors (IPs). Each of the five precursor types exhibits extensive(More)
Visual cortical areas subserve cognitive functions by interacting in both feedforward and feedback directions. While feedforward influences convey sensory signals, feedback influences modulate feedforward signaling according to the current behavioral context. We investigated whether these interareal influences are subserved differentially by rhythmic(More)
The afferent connectivity of areas V1 and V2 was investigated using the fluorescent dyes fast blue and diamidino yellow. Simultaneous injection of each dye in retinotopically corresponding regions of these areas gave rise to two afferent populations of labeled neurons in subcortical and cortical structures which project to both areas. These two populations(More)