scholarly journals What the Brain Stem Tells the Frontal Cortex. II. Role of the SC-MD-FEF Pathway in Corollary Discharge

2004 ◽  
Vol 91 (3) ◽  
pp. 1403-1423 ◽  
Author(s):  
Marc A. Sommer ◽  
Robert H. Wurtz
Keyword(s):  
Cerebral Cortex ◽  
Visual Field ◽  
Relay Node ◽  
Corollary Discharge ◽  
Frontal Eye Field ◽  
Double Step ◽  
Eye Field ◽  
Overall Performance ◽  
The Brain

One way we keep track of our movements is by monitoring corollary discharges or internal copies of movement commands. This study tested a hypothesis that the pathway from superior colliculus (SC) to mediodorsal thalamus (MD) to frontal eye field (FEF) carries a corollary discharge about saccades made into the contralateral visual field. We inactivated the MD relay node with muscimol in monkeys and measured corollary discharge deficits using a double-step task: two sequential saccades were made to the locations of briefly flashed targets. To make second saccades correctly, monkeys had to internally monitor their first saccades; therefore deficits in the corollary discharge representation of first saccades should disrupt second saccades. We found, first, that monkeys seemed to misjudge the amplitudes of their first saccades; this was revealed by systematic shifts in second saccade end points. Thus corollary discharge accuracy was impaired. Second, monkeys were less able to detect trial-by-trial variations in their first saccades; this was revealed by reduced compensatory changes in second saccade angles. Thus corollary discharge precision also was impaired. Both deficits occurred only when first saccades went into the contralateral visual field. Single-saccade generation was unaffected. Additional deficits occurred in reaction time and overall performance, but these were bilateral. We conclude that the SC-MD-FEF pathway conveys a corollary discharge used for coordinating sequential saccades and possibly for stabilizing vision across saccades. This pathway is the first elucidated in what may be a multilevel chain of corollary discharge circuits extending from the extraocular motoneurons up into cerebral cortex.

THE ROLE OF OESTROGENS IN SPONTANEOUS OVULATION: LOCATION OF SITE OF ACTION OF POSITIVE FEEDBACK OF OESTROGEN BY INTRACRANIAL IMPLANTATION OF THE ANTI-OESTROGEN I.C.I. 46474

1971 ◽  
Vol 50 (2) ◽  
pp. 321-327 ◽  
Author(s):  
J. G. BAINBRIDGE ◽  
A. P. LABHSETWAR
Keyword(s):  
Cerebral Cortex ◽  
Cocoa Butter ◽  
Median Eminence ◽  
Positive Feedback ◽  
Anterior Pituitary ◽  
Site Of Action ◽  
The Brain

SUMMARY In an attempt to locate the site(s) of action of the positive feedback of oestrogen for ovulation, a potent anti-oestrogen, I.C.I. 46474, was stereotaxically implanted into various parts of the brain or into the anterior pituitary. A dose of 5 μg of the anti-oestrogen when implanted into the cerebral cortex or injected subcutaneously on the morning of the day before pro-oestrus in 4-day cyclic rats was only marginally active in interfering with ovulation. By contrast, when the same amount was implanted into the median eminence region or the anterior pituitary, ovulation failed to occur in 80–100% of the rats (P < 0·05). Implantation of the cocoa butter vehicle alone into these regions interfered with ovulation in less than 35% of animals. Introduction of the anti-oestrogen into the anterior hypothalamic or mammillary region gave equivocal results. The data suggest that both the median eminence and the anterior pituitary contain receptors which can be blocked by the anti-oestrogen with resultant inhibition of ovulation. It is concluded that the positive feedback of oestrogen for ovulation is exerted both at the pituitary and the hypothalamic levels.

scholarly journals On the role of frontal eye field in guiding attention and saccades

2004 ◽  
Vol 44 (12) ◽  
pp. 1453-1467 ◽  
Author(s):  
Jeffrey D. Schall
Keyword(s):  
Frontal Eye Field ◽  
Eye Field

scholarly journals What the Brain Stem Tells the Frontal Cortex. I. Oculomotor Signals Sent From Superior Colliculus to Frontal Eye Field Via Mediodorsal Thalamus

2004 ◽  
Vol 91 (3) ◽  
pp. 1381-1402 ◽  
Author(s):  
Marc A. Sommer ◽  
Robert H. Wurtz
Keyword(s):  
Superior Colliculus ◽  
Frontal Cortex ◽  
Brain Stem ◽  
Signal Transmission ◽  
Frontal Eye Field ◽  
Visual Responses ◽  
Mediodorsal Thalamus ◽  
Visual Activity ◽  
Eye Field ◽  
The Brain

Neuronal processing in cerebral cortex and signal transmission from cortex to brain stem have been studied extensively, but little is known about the numerous feedback pathways that ascend from brain stem to cortex. In this study, we characterized the signals conveyed through an ascending pathway coursing from the superior colliculus (SC) to the frontal eye field (FEF) via mediodorsal thalamus (MD). Using antidromic and orthodromic stimulation, we identified SC source neurons, MD relay neurons, and FEF recipient neurons of the pathway in Macaca mulatta. The monkeys performed oculomotor tasks, including delayed-saccade tasks, that permitted analysis of signals such as visual activity, delay activity, and presaccadic activity. We found that the SC sends all of these signals into the pathway with no output selectivity, i.e., the signals leaving the SC resembled those found generally within the SC. Visual activity arrived in FEF too late to contribute to short-latency visual responses there, and delay activity was largely filtered out in MD. Presaccadic activity, however, seemed critical because it traveled essentially unchanged from SC to FEF. Signal transmission in the pathway was fast (∼2 ms from SC to FEF) and topographically organized (SC neurons drove MD and FEF neurons having similarly eccentric visual and movement fields). Our analysis of identified neurons in one pathway from brain stem to frontal cortex thus demonstrates that multiple signals are sent from SC to FEF with presaccadic activity being prominent. We hypothesize that a major signal conveyed by the pathway is corollary discharge information about the vector of impending saccades.

scholarly journals The role of monkey frontal eye field in visual categorization

2010 ◽  
Vol 8 (6) ◽  
pp. 374-374
Author(s):  
V. Ferrera ◽  
M. Yanike ◽  
C. Cassanello
Keyword(s):  
Frontal Eye Field ◽  
Visual Categorization ◽  
Eye Field

A causal role of the frontal eye field in visual stability during optokinetic stimulation: TMS-EEG evidence

2019 ◽  
Vol 12 (2) ◽  
pp. 451
Author(s):  
A. Mastropasqua ◽  
J. Dowsett ◽  
M. Dieterich ◽  
P. Taylor
Keyword(s):  
Causal Role ◽  
Frontal Eye Field ◽  
Optokinetic Stimulation ◽  
Visual Stability ◽  
Eye Field

scholarly journals Effect of Inactivation of the Cortical Frontal Eye Field on Saccades Generated in a Choice Response Paradigm

2008 ◽  
Vol 100 (5) ◽  
pp. 2726-2737 ◽  
Author(s):  
Edward L. Keller ◽  
Kyoung-Min Lee ◽  
Se-Woong Park ◽  
Jessica A. Hill
Keyword(s):  
Alternative Interpretation ◽  
Saccade Latency ◽  
Frontal Eye Field ◽  
Choice Response ◽  
Visually Guided ◽  
Eye Field ◽  
Saccade Direction ◽  
Response Task ◽  
Bilateral Lesions

Previous studies using muscimol inactivations in the frontal eye fields (FEFs) have shown that saccades generated by recall from working memory are eliminated by these lesions, whereas visually guided saccades are relatively spared. In these experiments, we made reversible inactivations in FEFs in alert macaque monkeys and examined the effect on saccades in a choice response task. Our task required monkeys to learn arbitrary pairings between colored stimuli and saccade direction. Following inactivations, the percentage of choice errors increased as a function of the number of alternative (NA) pairings. In contrast, the percentage of dysmetric saccades (saccades that landed in the correct quadrant but were inaccurate) did not vary with NA. Saccade latency increased postlesion but did not increase with NA. We also made simultaneous inactivations in both FEFs. The results following bilateral lesions showed approximately twice as many choice errors. We conclude that the FEFs are involved in the generation of saccades in choice response tasks. The dramatic effect of NA on choice errors, but the lack of an effect of NA on motor errors or response latency, suggests that two types of processing are interrupted by FEF lesions. The first involves the formation of a saccadic intention vector from associate memory inputs, and the second, the execution of the saccade from the intention vector. An alternative interpretation of the first result is that a role of the FEFs may be to suppress incorrect responses. The doubling of choice errors following bilateral FEF lesions suggests that the effect of unilateral lesions is not caused by a general inhibition of the lesioned side by the intact side.

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