Interaction of the Movements of the Two Eyecups in the Crab Carcinus

1969 ◽  
Vol 50 (3) ◽  
pp. 651-671 ◽  
Author(s):  
W. J. P. BARNES ◽  
G. A. HORRIDGE
Keyword(s):  
Optokinetic Nystagmus ◽  
Visual Stimuli ◽  
The Other ◽  
Sinusoidal Oscillation ◽  
Fast Phase ◽  
Visual Inputs ◽  
Optokinetic Responses ◽  
Normal Frequency ◽  
Perceived Motion ◽  
The Brain

1. The movements of the two eyecups of the crab, Carcinus, have been recorded simultaneously during optokinetic responses. 2. Experiments in which the eyes view different visual stimuli reveal that, at the start of a response, the eyecups have a considerable degree of independence and can even move in opposite directions. As the response progresses, interaction between the eyes increases, until the eyecups move at similar velocities in the direction of the slower of the two visual inputs, or are stationary. 3. Similar interactions between the eyes were observed during memory responses and during the responses to sinusoidal oscillation of the two sets of stripes. Each eye has its own system for converting perceived motion into eyecup movement. These two systems are linked on the afferent rather than the efferent side of the brain. 5. The fast phase of optokinetic nystagmus is governed by the eye whose fast-phase movement occurs away from the midline, and the fast phases of this eyecup lead the other by 30-80 msec. Also, fast phases only occur at their normal frequency when the governing eye can see the stripes.

Analysis of the Correlation between Static Visual Stimuli, Eye Movements, and Brain Signals

2021 ◽  
pp. 2150056
Author(s):  
Hamidreza Namazi ◽  
Avinash Menon ◽  
Ondrej Krejcar
Keyword(s):  
Eye Movements ◽  
Visual Stimuli ◽  
Research Area ◽  
The Other ◽  
Important Research ◽  
Eeg Signals ◽  
Brain Signals ◽  
Information Contents ◽  
Important Research Area ◽  
The Brain

Analysis of the correlation among the activities of the eyes and brain is an important research area in physiological science. In this paper, we analyzed the correlation between the reactions of eyes and the brain during rest and while watching different visual stimuli. Since every external stimulus transfers information to the human brain, and on the other hand, eye movements and EEG signals contain information, we utilized Shannon entropy to evaluate the coupling between them. In the experiment, 10 subjects looked at 4 images with different information contents while we recorded their EEG signals and eye movements simultaneously. According to the results, the information contents of eye fluctuations, EEG signals, and visual stimuli are coupled, which reflect the coupling between the brain and eye activities. Similar analyses could be performed to evaluate the correlation among the activities of other organs versus the brain.

Localisation of Auditory Targets during Optokinetic Nystagmus

Perception ◽  
10.1068/p5849 ◽  
2007 ◽  
Vol 36 (10) ◽  
pp. 1507-1512 ◽  
Author(s):  
Kerstin Königs ◽  
Jonas Knöll ◽  
Frank Bremmer
Keyword(s):  
Eye Movements ◽  
Eye Movement ◽  
Temporal Pattern ◽  
Optokinetic Nystagmus ◽  
Visual Stimuli ◽  
Spatial Location ◽  
Neural Mechanisms ◽  
Auditory Target ◽  
Auditory Stimuli ◽  
Fast Phase

Previous studies have shown that the perceived location of visual stimuli briefly flashed during smooth pursuit, saccades, or optokinetic nystagmus (OKN) is not veridical. We investigated whether these mislocalisations can also be observed for brief auditory stimuli presented during OKN. Experiments were carried out in a lightproof sound-attenuated chamber. Participants performed eye movements elicited by visual stimuli. An auditory target (white noise) was presented for 5 ms. Our data clearly indicate that auditory targets are mislocalised during reflexive eye movements. OKN induces a shift of perceived location in the direction of the slow eye movement and is modulated in the temporal vicinity of the fast phase. The mislocalisation is stronger for look- as compared to stare-nystagmus. The size and temporal pattern of the observed mislocalisation are different from that found for visual targets. This suggests that different neural mechanisms are at play to integrate oculomotor signals and information on the spatial location of visual as well as auditory stimuli.

MICROCHEMICAL ASSAYS OF GLUCOSE AND GLUCOSE-6-PHOSPHATE IN MAMMALIAN PANCREATIC β-CELLS

1968 ◽  
Vol 59 (3) ◽  
pp. 479-486 ◽  
Author(s):  
Lars-Ake Idahl ◽  
Bo Hellman
Keyword(s):  
Glucose Level ◽  
Exocrine Pancreas ◽  
The Other ◽  
Wide Concentration Range ◽  
Β Cells ◽  
Pancreatic Β Cells ◽  
Enzymatic Cycling ◽  
Glucose Diffusion ◽  
Significant Barrier ◽  
The Brain

ABSTRACT The combination of enzymatic cycling and fluorometry was used for measuring glucose and glucose-6-phosphate in pancreatic β-cells from obese-hyperglycaemic mice. The glucose level of the β-cells corresponded to that of serum over a wide concentration range. In the exocrine pancreas, on the other hand, a significant barrier to glucose diffusion across the cell membranes was demonstrated. During 5 min of ischaemia, the glucose level remained practically unchanged in the β-cells while it increased in the liver and decreased in the brain. The observation that the pancreatic β-cells are characterized by a relatively low ratio of glucose-6-phosphate to glucose may be attributed to the presence of a specific glucose-6-phosphatase.

The Dioptrique

2017 ◽  
Author(s):  
Walter Ott
Keyword(s):  
Sensory Experience ◽  
The Other ◽  
Brain Image ◽  
Brain Motion ◽  
Natural Geometry ◽  
The Common ◽  
The Brain

Descartes’s treatment of perception in the Optics, though published before the Meditations, contains a distinct account of sensory experience. The end of the chapter suggests some reasons for this oddity, but that the two accounts are distinct is difficult to deny. Descartes in the present work topples the brain image from its throne. In its place, we have two mechanisms, one purely causal, the other inferential. Where the proper sensibles are concerned, the ordination of nature suffices to explain why a given sensation is triggered on the occasion of a given brain motion. The same is true with regard to the common sensibles. But on top of this purely causal story, Descartes re-introduces his doctrine of natural geometry.

Relief of facial pain after combined removal of precentral and postcentral cortex

1971 ◽  
Vol 34 (4) ◽  
pp. 537-543 ◽  
Author(s):  
Richard A. Lende ◽  
Wolff M. Kirsch ◽  
Ralph Druckman
Keyword(s):  
Facial Pain ◽  
The Other ◽  
Precentral Gyrus ◽  
Nerve Section ◽  
Content Type ◽  
Burning Pain ◽  
Cortical Localization ◽  
The Brain ◽  
Fine Print ◽  
Frontal Lobotomy

✓ Cortical removals which included precentral and postcentral facial representations resulted in relief of facial pain in two patients. Because of known failures following only postcentral (SmI) ablations, these operations were designed to eliminate also the cutaneous afferent projection to the precentral gyrus (MsI) and the second somatic sensory area (SmII). In one case burning pain developed after a stroke involving the brain stem and was not improved by total fifth nerve section; prompt relief followed corticectomy and lasted until death from heart disease 20 months later. In the other case persistent steady pain that developed after fifth rhizotomy for trigeminal neuralgia proved refractory to frontal lobotomy; relief after corticectomy was immediate and has lasted 14 months. Cortical localization was established by stimulation under local anesthesia. Each removal extended up to the border of the arm representation and down to the upper border of the insula. Such a resection necessarily included SmII, and in one case responses presumably from SmII were obtained before removal. The suggestions of Biemond (1956) and Poggio and Mountcastle (1960) that SmII might be concerned with pain sensibility may be pertinent in these cases.

Detection of Intracranial Signatures of Interictal Epileptiform Discharges from Concurrent Scalp EEG

2016 ◽  
Vol 26 (04) ◽  
pp. 1650016 ◽  
Author(s):  
Loukianos Spyrou ◽  
David Martín-Lopez ◽  
Antonio Valentín ◽  
Gonzalo Alarcón ◽  
Saeid Sanei
Keyword(s):  
Detection Algorithm ◽  
The Other ◽  
Intracranial Eeg ◽  
Scalp Eeg ◽  
Epileptiform Discharges ◽  
Interictal Epileptiform Discharges ◽  
Scalp Electroencephalogram ◽  
Patients With Epilepsy ◽  
Electrical Activities ◽  
The Brain

Interictal epileptiform discharges (IEDs) are transient neural electrical activities that occur in the brain of patients with epilepsy. A problem with the inspection of IEDs from the scalp electroencephalogram (sEEG) is that for a subset of epileptic patients, there are no visually discernible IEDs on the scalp, rendering the above procedures ineffective, both for detection purposes and algorithm evaluation. On the other hand, intracranially placed electrodes yield a much higher incidence of visible IEDs as compared to concurrent scalp electrodes. In this work, we utilize concurrent scalp and intracranial EEG (iEEG) from a group of temporal lobe epilepsy (TLE) patients with low number of scalp-visible IEDs. The aim is to determine whether by considering the timing information of the IEDs from iEEG, the resulting concurrent sEEG contains enough information for the IEDs to be reliably distinguished from non-IED segments. We develop an automatic detection algorithm which is tested in a leave-subject-out fashion, where each test subject’s detection algorithm is based on the other patients’ data. The algorithm obtained a [Formula: see text] accuracy in recognizing scalp IED from non-IED segments with [Formula: see text] accuracy when trained and tested on the same subject. Also, it was able to identify nonscalp-visible IED events for most patients with a low number of false positive detections. Our results represent a proof of concept that IED information for TLE patients is contained in scalp EEG even if they are not visually identifiable and also that between subject differences in the IED topology and shape are small enough such that a generic algorithm can be used.

scholarly journals THE PATHOLOGIC EFFECTS OF STREPTOCOCCI FROM CASES OF POLIOMYELITIS AND OTHER SOURCES

1917 ◽  
Vol 25 (4) ◽  
pp. 557-580 ◽  
Author(s):  
Carroll G. Bull
Keyword(s):  
Spinal Cord ◽  
Guinea Pigs ◽  
The Other ◽  
Laboratory Animals ◽  
Histological Changes ◽  
Other Hand ◽  
Brain And Spinal Cord ◽  
The Brain

Streptococci cultivated from the tonsils of thirty-two cases of poliomyelitis were used to inoculate various laboratory animals. In no case was a condition induced resembling poliomyelitis clinically or pathologically in guinea pigs, dogs, cats, rabbits, or monkeys. On the other hand, a considerable percentage of the rabbits and a smaller percentage of some of the other animals developed lesions due to streptococci. These lesions consisted of meningitis, meningo-encephalitis, abscess of the brain, arthritis, tenosynovitis, myositis, abscess of the kidney, endocarditis, pericarditis, and neuritis. No distinction in the character or frequency of the lesions could be determined between the streptococci derived from poliomyelitic patients and from other sources. Streptococci isolated from the poliomyelitic brain and spinal cord of monkeys which succumbed to inoculation with the filtered virus failed to induce in monkeys any paralysis or the characteristic histological changes of poliomyelitis. These streptococci are regarded as secondary bacterial invaders of the nervous organs. Monkeys which have recovered from infection with streptococci derived from cases of poliomyelitis are not protected from infection with the filtered virus, and their blood does not neutralize the filtered virus in vitro. We have failed to detect any etiologic or pathologic relationship between streptococci and epidemic poliomyelitis in man or true experimental poliomyelitis in the monkey.

Musical training improves memory for instrumental music, but not vocal music or words

2018 ◽  
Vol 48 (1) ◽  
pp. 150-159
Author(s):  
Jonathan M. P. Wilbiks ◽  
Sean Hutchins
Keyword(s):  
Instrumental Music ◽  
Musical Training ◽  
Vocal Music ◽  
Verbal Material ◽  
The Other ◽  
Musical Experience ◽  
Facilitative Effect ◽  
Musical Excerpts ◽  
And Performance ◽  
The Brain

In previous research, there exists some debate about the effects of musical training on memory for verbal material. The current research examines this relationship, while also considering musical training effects on memory for musical excerpts. Twenty individuals with musical training were tested and their results were compared to 20 age-matched individuals with no musical experience. Musically trained individuals demonstrated a higher level of memory for classical musical excerpts, with no significant differences for popular musical excerpts or for words. These findings are in support of previous research showing that while music and words overlap in terms of their processing in the brain, there is not necessarily a facilitative effect between training in one domain and performance in the other.

Beyond the Reward Pathway: Coding Reward Magnitude and Error in the Rat Subthalamic Nucleus

2009 ◽  
Vol 102 (4) ◽  
pp. 2526-2537 ◽  
Author(s):  
Sylvie Lardeux ◽  
Remy Pernaud ◽  
Dany Paleressompoulle ◽  
Christelle Baunez
Keyword(s):  
Subthalamic Nucleus ◽  
Firing Pattern ◽  
Sucrose Solution ◽  
Critical Role ◽  
The Other ◽  
Reward Circuitry ◽  
Reward Delivery ◽  
Reward Pathway ◽  
Subthalamic Neurons ◽  
The Brain

It was recently shown that subthalamic nucleus (STN) lesions affect motivation for food, cocaine, and alcohol, differentially, according to either the nature of the reward or the preference for it. The STN may thus code a reward according to its value. Here, we investigated how the firing of subthalamic neurons is modulated during expectation of a predicted reward between two possibilities (4 or 32% sucrose solution). The firing pattern of neurons responding to predictive cues and to reward delivery indicates that STN neurons can be divided into subpopulations responding specifically to one reward and less or giving no response to the other. In addition, some neurons (“oops” neurons) specifically encode errors as they respond only during error trials. These results reveal that the STN plays a critical role in ascertaining the value of the reward and seems to encode that value differently depending on the magnitude of the reward. These data highlight the importance of the STN in the reward circuitry of the brain.

Apparent Higher Brain Weight in Suicide Victims: Possible Reasons

2002 ◽  
Vol 90 (1) ◽  
pp. 236-238 ◽  
Author(s):  
Jože Balažic ◽  
Andrej Marušič
Keyword(s):  
Postmortem Examination ◽  
Brain Weight ◽  
The Other ◽  
Emotional Information ◽  
Partial Explanation ◽  
Suicide Methods ◽  
Surrounding Environment ◽  
Significant Difference ◽  
Self Harm ◽  
The Brain

In 2000 we tested previously reported findings by Salib and Tadros that brain weight of fatal self-harm victims is higher than of those who died of natural causes. Our results were based on data from 15 suicides and 15 deaths of other causes. Data included matching variables of age, sex, time between death and postmortem examination, and temperature of the surrounding environment. The exploratory variables were brain weight and method of death. No significant difference was found between the brain weights of suicides and others. On the other hand, some differences were obtained for different suicide methods, which also differed in the temperature of the environment, this being lower for the group of suicides that occurred outdoors (around or below 0°C). Once we excluded all the outdoor cases and controls, a significantly higher brain weight was obtained for suicide cases. These and previous results are intriguing and require explanation. Respirator brain syndrome as described by Moseley, Molinari, and Walker in 1976 may provide only a partial explanation. Another possible suggestion is that higher brain weight in suicide victims may be related to previously demonstrated increased amygdala blood flow and subsequent amygdala enlargement due to the increased processing of emotional information.

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