Human Sleep, Sleep Loss and Behaviour

1993 ◽  
Vol 162 (3) ◽  
pp. 413-419 ◽  
Author(s):  
J. A. Horne

The prefrontal cortex (PFC) consists of the cortex lying in front of the primary and secondary motor cortex, and includes the dorsolateral and orbital areas, frontal eye fields, and Broca's area. Not all of the functions of the PFC are known, but key ones are the maintenance of wakefulness and non-specific arousal, and the recruiting of various cortical areas required to deal with tasks in hand (Luria, 1973; Stuss & Benson, 1986; Fuster, 1989). Other roles include (Kolb & Whishaw, 1985) planning, sensory comparisons, discrimination, decisions for action, direction and maintenance of attention at a specific task, execution of associated scanning eye movements, and initiation and production of novel goal-directed behaviour (especially with speech). Of the senses, vision makes a particular demand of the PFC, and this is reflected by the frontal eye fields.

2001 ◽  
Vol 95 (5) ◽  
pp. 804-815 ◽  
Author(s):  
Elie Lobel ◽  
Philippe Kahane ◽  
Ute Leonards ◽  
Marie-Hélène Grosbras ◽  
Stéphane Lehéricy ◽  
...  

Object. The goal of this study was to investigate the anatomical localization and functional role of human frontal eye fields (FEFs) by comparing findings from two independently conducted studies. Methods. In the first study, 3-tesla functional magnetic resonance (fMR) imaging was performed in 14 healthy volunteers divided into two groups: the first group executed self-paced voluntary saccades in complete darkness and the second group repeated newly learned or familiar sequences of saccades. In the second study, intracerebral electrical stimulation (IES) was performed in 38 patients with epilepsy prior to surgery, and frontal regions where stimulation induced versive eye movements were identified. These studies showed that two distinct oculomotor areas (OMAs) could be individualized in the region classically corresponding to the FEFs. One OMA was consistently located at the intersection of the superior frontal sulcus with the fundus of the superior portion of the precentral sulcus, and was the OMA in which saccadic eye movements could be the most easily elicited by electrical stimulation. The second OMA was located more laterally, close to the surface of the precentral gyrus. The fMR imaging study and the IES study demonstrated anatomical and stereotactic agreement in the identification of these cortical areas. Conclusions. These findings indicate that infracentimetric localization of cortical areas can be achieved by measuring the vascular signal with the aid of 3-tesla fMR imaging and that neuroimaging and electrophysiological recording can be used together to obtain a better understanding of the human cortical functional anatomy.


2019 ◽  
Author(s):  
Ahmad Yousef

This proposal offers perspective and challenges aiming to optimize and socialize the humanoid eyes. The main purpose of this proposal is to bring the readers’ attention to the importance and the sophistication of the human eye and its four dynamics continuum, namely, the continuum that may include saccadic eye movements, pupil variations, blinks along with duchenne markers. We suggested that the robotics’ designers to work collaboratively with neuroscientists to mathematically estimate the aforementioned continuum, and therefore, humanoid eyes/cameras can be perfectly invented; invention that we try to register its essential elements in the present study. The aforementioned collaboration will be very beneficial for an additional purpose, namely, because human vision indeed activates very many cortical areas that extended to the prefrontal cortex; the collaboration may effectively flourish the eye trackers to be good replacements of the expensive brain imaging in certain circumstances.


2014 ◽  
Vol 111 (4) ◽  
pp. 787-803 ◽  
Author(s):  
Michael J. Koval ◽  
R. Matthew Hutchison ◽  
Stephen G. Lomber ◽  
Stefan Everling

The dorsolateral prefrontal cortex (dlPFC) and anterior cingulate cortex (ACC) have both been implicated in the cognitive control of saccadic eye movements by single neuron recording studies in nonhuman primates and functional imaging studies in humans, but their relative roles remain unclear. Here, we reversibly deactivated either dlPFC or ACC subregions in macaque monkeys while the animals performed randomly interleaved pro- and antisaccades. In addition, we explored the whole-brain functional connectivity of these two regions by applying a seed-based resting-state functional MRI analysis in a separate cohort of monkeys. We found that unilateral dlPFC deactivation had stronger behavioral effects on saccades than unilateral ACC deactivation, and that the dlPFC displayed stronger functional connectivity with frontoparietal areas than the ACC. We suggest that the dlPFC plays a more prominent role in the preparation of pro- and antisaccades than the ACC.


1994 ◽  
Vol 6 (4) ◽  
pp. 400-411 ◽  
Author(s):  
Avishai Henik ◽  
Robert Rafal ◽  
Dell Rhodes

Nine patients with chronic, unilateral lesions of the dorso-lateral prefrontal cortex including the frontal eye fields (FEF) made saccades toward contralesional and ipsilesional fields. The saccades were either voluntarily directed in response to arrows in the center of a visual display, or were reflexively summoned by a peripheral visual signal. Saccade latencies were compared to those made by seven neurologic control patients with chronic, unilateral lesions of dorsolateral prefrontal cortex sparing the FEF, and by 13 normal control subjects. In both the normal and neurologic control subjects, reflexive saccades had shorter Latencies than voluntary saccades. In the FEF lesion patients, voluntary saccades had longer latencies toward the contralesional field than toward the ipsilesional field. The opposite pattern was found for reflexive saccades: latencies of saccades to targets in the contralesional field were shorter than saccades summoned to ipsilesional targets. Reflexive saccades toward the ipsilesional field had abnormally prolonged latencies; they were comparable to the latencies observed for voluntary Saccades. The effect of FEF lesions on saccacles contrasted with those observed in a second experiment requiring a key press response: FEF lesion patients were slower in making key press responses to signals detected in the contralesional field. To assess covert attention and preparatory set the effects of precues providing advance information were measured in both saccade and key press experiments. Neither patient group showed any deficiency in using precues to shift attention or to prepare saccades. The FEF facilitates the generation of voluntary saccatles and also inhibits reflexive saccades to exogenous signals. FEF lesions may disinhibit the ipsilesional midbrain which in turn may inhibit the opposite colliculus to slow reflexive saccades toward the ipsilesional field.


2007 ◽  
Vol 24 (8) ◽  
pp. 1362-1377 ◽  
Author(s):  
Dorota Sulejczak ◽  
Ewelina Ziemlińska ◽  
Julita Czarkowska-Bauch ◽  
Ewa Nosecka ◽  
Ryszard Strzalkowski ◽  
...  

2013 ◽  
Vol 76 (3) ◽  
pp. 141-149 ◽  
Author(s):  
Shigehiro Miyachi ◽  
Yoshihiro Hirata ◽  
Ken-ichi Inoue ◽  
Xiaofeng Lu ◽  
Atsushi Nambu ◽  
...  

Author(s):  
Shirley H. Wray

discusses the brain’s visual architecture for directing and controlling of eye movements:the striate, frontal and parietal cortical areas; and the eye movements themselves—saccades, smooth pursuit, and vergence. The susceptibility to disorders of these systems is illustrated in four detailed cases that follow disease progression from initial symptoms and signs to diagnosis and treatment. The case studies and video displays include a patient with Pick’s disease (frontotemporal dementia), another with Alzheimer’s dementia, and two examples of rare saccadic syndromes, one a patient with the slow saccade syndrome due to progressive supranuclear palsy and one with selective saccadic palsy following cardiac surgery.


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