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Experiments were made on the posterior parietal association cortical areas 5 and in 17 hemispheres of 11 monkeys, 6 M. mulatta and 5 M. arctoides. The electrical signs of the activity of single cortical cells were recorded with microelectrodes in waking animals as they carried out certain behavioral acts in response to a series of sensory cues. The(More)
We measured the capacity of monkeys to project the arm to visually located targets under conditions differing in the nature of visual control allowed during reaching. This capacity was impaired by a unilateral posterior parietal lesion which increased the magnitude and variability of errors in projecting the contralateral arm to targets located on either(More)
Neuropsychiatric imaging remains a pioneering frontier in modern medicine. Recent decades have witnessed marked advances in identifying biological correlates for a broad array of illnesses (Hillary et al. However, our understanding of the underlying pathophysiology of neuropsychiatric illnesses remains insufficient (Ecker et al., 2010; Linden, 2012).(More)
In the absence of a direct geniculate input, area 17 cells in the cat are nevertheless able to respond to visual stimuli because of feedback connections from area 18. Anatomic studies have shown that, in the cat visual cortex, layer 5 of area 18 projects to layer 5 of area 17, and layers 2/3 of area 18 project to layers 2/3 of area 17. What is the specific(More)
869 ments in a patient recovering from optic ataxia. (1975). Posterior parietal association cortex of the monkey: Command functions for operations within extraper-sonal space. (1984). Looking and seeing: The visual functions of the parietal lobe.movement–related neurons of the posterior parietal cortex of the monkey: Their role in visual guidance of hand(More)
BACKGROUND Apomixis is an alternative route of plant reproduction that produces individuals genetically identical to the mother plant through seeds. Apomixis is desirable in agriculture, because it guarantees the perpetuation of superior genotypes (i.e. heterotic hybrid seeds) by self-seeding without loss of hybrid vigour. The Paspalum genus, an archetypal(More)
1. We iontophoretically applied NG-nitro-L-arginine (L-NOArg), an inhibitor of nitric oxide synthase (NOS), to cells (n = 77) in area 17 of anaesthetized and paralysed cats while recording single-unit activity extracellularly. In twenty-nine out of seventy-seven cells (38%), compounds altering NO levels affected visual responses. 2. In twenty-five out of(More)
We have shown that application of an inhibitor of the enzyme nitric oxide synthase (NOS) effectively suppresses the visual responses of relay cells in the dorsal lateral geniculate nucleus (dLGN) of the anaesthetized paralysed cat. Such suppression seems to result from a specific reduction in transmission via N-methyl-D-aspartic acid (NMDA) receptors, since(More)
Orientation discrimination, the capacity to recognize an orientation difference between two lines presented at different times, probably involves cortical processes such as stimuli encoding, holding them in memory, comparing them, and then deciding. To correlate discrimination with neural activity in combined psychophysical and electrophysiological(More)
Selection of the appropriate action in a changing environment involves a chain of events that goes from perception through decision to action and evaluation of the outcomes. What and where in the brain are the correlates of these events? The ventral premotor cortex (PMv) is a candidate because (1) it is involved in sensory transformations for visually(More)