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Human Eye movement

Johannes Rennig, Michael S Beauchamp
During face-to-face communication, the mouth of the talker is informative about speech content, while the eyes of the talker convey other information, such as gaze location. Viewers most often fixate either the mouth or the eyes of the talker's face, presumably allowing them to sample these different sources of information. To study the neural correlates of this process, healthy humans freely viewed talking faces while brain activity was measured with BOLD fMRI and eye movements were recorded with a video-based eye tracker...
August 6, 2018: NeuroImage
Anshul Srivastava, Omar F Ahmad, Christopher Pham Pacia, Mark Hallett, Codrin Lungu
Human locomotion involves a complex interplay among multiple brain regions and depends on constant feedback from the visual system. We summarize here the current understanding of the relationship among fixations, saccades, and gait as observed in studies sampling eye movements during locomotion, through a review of the literature and a synthesis of the relevant knowledge on the topic. A significant overlap in locomotor and saccadic neural circuitry exists that may support this relationship. Several animal studies have identified potential integration nodes between these overlapping circuitries...
August 9, 2018: Journal of Movement Disorders
Marshall A Dalton, Peter Zeidman, Cornelia McCormick, Eleanor A Maguire
The hippocampus is known to be important for a range of cognitive functions including episodic memory, spatial navigation and future-thinking. Wide agreement on the exact nature of its contribution has proved elusive, with some theories emphasising associative processes and another proposing that scene construction is its primary role. To directly compare these accounts of hippocampal function in human males and females, we devised a novel mental imagery paradigm where different tasks were closely matched for associative processing and mental construction, but either did or did not evoke scene representations, and we combined this with high resolution functional MRI...
August 6, 2018: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
Mark P McAvoy, Enzo Tagliazucchi, Helmut Laufs, Marcus E Raichle
A hallmark of non-rapid eye movement (REM) sleep is the decreased brain activity as measured by global reductions in cerebral blood flow, oxygen metabolism, and glucose metabolism. It is unknown whether the blood oxygen level dependent (BOLD) signal undergoes similar changes. Here we show that, in contrast to the decreases in blood flow and metabolism, the mean global BOLD signal increases with sleep depth in a regionally non-uniform manner throughout gray matter. We relate our findings to the circulatory and metabolic processes influencing the BOLD signal and conclude that because oxygen consumption decreases proportionately more than blood flow in sleep, the resulting decrease in paramagnetic deoxyhemoglobin accounts for the increase in mean global BOLD signal...
August 3, 2018: Journal of Cerebral Blood Flow and Metabolism
Hoi-Kei Lon, Nuno Mendonca, Sandra Goss, Ahmed A Othman, Charles Locke, Ziyi Jin, Beatrice Rendenbach-Mueller
Alicapistat is an orally active selective inhibitor of calpain 1 and 2 whose overactivation has been linked to Alzheimer disease (AD). Three studies were conducted in healthy subjects (18-55 years), 1 in healthy elderly subjects (≥65 years), and 1 in patients with mild to moderate AD. Four studies assessed pharmacokinetics, 1 study in healthy subjects assessed pharmacodynamics (sleep parameters, particularly rapid eye movement [REM], as a measure of central nervous system [CNS] penetration and activity), and all studies assessed safety...
July 27, 2018: Clinical Pharmacology in Drug Development
Tarkeshwar Singh, Christopher M Perry, Stacy L Fritz, Julius Fridriksson, Troy M Herter
BACKGROUND: Humans use voluntary eye movements to actively gather visual information during many activities of daily living, such as driving, walking, and preparing meals. Most stroke survivors have difficulties performing these functional motor tasks, and we recently demonstrated that stroke survivors who require many saccades (rapid eye movements) to plan reaching movements exhibit poor motor performance. However, the nature of this relationship remains unclear. OBJECTIVE: Here we investigate if saccades interfere with speed and smoothness of reaching movements in stroke survivors, and if excessive saccades are associated with difficulties performing functional tasks...
July 25, 2018: Neurorehabilitation and Neural Repair
Marta Pace, Millene R Camilo, Andrea Seiler, Simone B Duss, Johannes Mathis, Mauro Manconi, Claudio L Bassetti
Study Objectives: Sleep disturbances are common in acute stroke patients and are linked with a negative stroke outcome. However, it is also unclear which and how such changes may be related to stroke outcome. To explore this link, we performed a sleep-EEG study in animals and humans after ischemic stroke. Methods: (1) Animal-study: 12 male rats were assigned to two groups: ischemia (IS) and sham-surgery (Sham). In both groups, sleep architecture was investigated 24h before surgery and for the following 3 days...
July 19, 2018: Sleep
Markus H Schmidt
Michel Jouvet established a tradition of sleep neurophysiology that inspired several generations of sleep researchers. When I arrived in his laboratory in 1991, it was known that erection cycles occur during rapid eye movement (REM) sleep in humans. However, it was not known if such erections in sleep occurred in other species, or how REM-related erections were controlled. Employing the classical techniques and systematic approach of Jouvet and his team, I embarked on a journey of discovery. Not only were fundamental principles of REM-related erectile control identified, such as the critical role of the lateral preoptic area in the forebrain, but I also gained a deep appreciation of the scientific approach in the Jouvet tradition...
June 15, 2018: Sleep Medicine
Claes von Hofsten, Kerstin Rosander
Infancy is the most dynamic part of human development. During this period, all basic sensorimotor and cognitive abilities are established. In this chapter, we will trace some of the important achievements of this development with a focus on how infants achieve predictive control of actions, i.e., how they come to coordinate their behavior with the ongoing events in the world without lagging behind. With the maturation of the brain, new possibilities that have profound effects on cognition open up. Some of them are core abilities, i...
2018: Advances in Child Development and Behavior
Michele Rucci, Jonathan D Victor
During development, the eye tunes its size to its optics so that distant objects are in focus, a state known as emmetropia. Although multiple factors contribute to this process, a strong influence appears to be exerted by the visual input signals entering the eye. Much research has been dedicated to the possible roles of specific features of the retinal image, such as the magnitude of blur. However, in humans and other species, the input to the retina is not an image, but a spatiotemporal flow of luminance...
July 2, 2018: Journal of Vision
Ewen B Lavoie, Aïda M Valevicius, Quinn A Boser, Ognjen Kovic, Albert H Vette, Patrick M Pilarski, Jacqueline S Hebert, Craig S Chapman
This study explores the role that vision plays in sequential object interactions. We used a head-mounted eye tracker and upper-limb motion capture to quantify visual behavior while participants performed two standardized functional tasks. By simultaneously recording eye and motion tracking, we precisely segmented participants' visual data using the movement data, yielding a consistent and highly functionally resolved data set of real-world object-interaction tasks. Our results show that participants spend nearly the full duration of a trial fixating on objects relevant to the task, little time fixating on their own hand when reaching toward an object, and slightly more time-although still very little-fixating on the object in their hand when transporting it...
June 1, 2018: Journal of Vision
Eric S Seemiller, Bruce G Cumming, T Rowan Candy
Vergence is defined as a binocular eye movement during which the two eyes move in opposite directions to align to a target in depth. In adults, fine vergence control is driven primarily by interocular retinal image disparity. Although infants have not typically been shown to respond to disparity until 3 to 5 months postpartum, they have been shown to align their eyes from hours after birth. It remains unclear what drives these responses in young infants. In this experiment, 5- to 10-week-old human infants were presented with a dynamic random noise stimulus oscillating in disparity at 0...
June 1, 2018: Journal of Vision
John M Henderson, Taylor R Hayes
We compared the influence of meaning and of salience on attentional guidance in scene images. Meaning was captured by "meaning maps" representing the spatial distribution of semantic information in scenes. Meaning maps were coded in a format that could be directly compared to maps of image salience generated from image features. We investigated the degree to which meaning versus image salience predicted human viewers' spatiotemporal distribution of attention over scenes. Extending previous work, here the distribution of attention was operationalized as duration-weighted fixation density...
June 1, 2018: Journal of Vision
Edward C Harding, Xiao Yu, Andawei Miao, Nathanael Andrews, Ying Ma, Zhiwen Ye, Leda Lignos, Giulia Miracca, Wei Ba, Raquel Yustos, Alexei L Vyssotski, William Wisden, Nicholas P Franks
Mammals, including humans, prepare for sleep by nesting and/or curling up, creating microclimates of skin warmth. To address whether external warmth induces sleep through defined circuitry, we used c-Fos-dependent activity tagging, which captures populations of activated cells and allows them to be reactivated to test their physiological role. External warming tagged two principal groups of neurons in the median preoptic (MnPO)/medial preoptic (MPO) hypothalamic area. GABA neurons located mainly in MPO produced non-rapid eye movement (NREM) sleep but no body temperature decrease...
July 23, 2018: Current Biology: CB
Zachary M Abzug, Marc A Sommer
Human behavior is influenced by serial decision-making: past decisions affect choices that set the context for selecting future options. A primate brain region that may be involved in linking decisions across time is the supplementary eye field (SEF), which, in addition to its well-known visual responses and saccade-related activity, also signals the rules that govern flexible decisions and the outcomes of those decisions. Our hypotheses were that SEF neurons encode events during serial decision-making and link the sequential decisions with sustained activity...
July 16, 2018: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
Jessica L Yorzinski, Maria E Tovar, Richard G Coss
Even prey that successfully evade attack incur costs when responding to predators. These nonlethal costs can impact their reproductive success and survival. One strategy that prey can use to minimize these costs is to adjust their antipredator behavior based on the perceived level of risk. We tested whether humans adopt this strategy by presenting participants with photographic arrays of predators (lions) that varied in their level of risk. While their eye movements were recorded, the participants searched for a forward-facing predator (signifying potential predator interest; high-risk target) among an array of inattentive predators that were facing away (low-risk distractors) or searched for a predator that was facing away from them among an array of forward-facing predators...
July 16, 2018: Journal of Comparative Psychology
Zhongxing Zhang, Geert Mayer, Yves Dauvilliers, Giuseppe Plazzi, Fabio Pizza, Rolf Fronczek, Joan Santamaria, Markku Partinen, Sebastiaan Overeem, Rosa Peraita-Adrados, Antonio Martins da Silva, Karel Sonka, Rafael Del Rio-Villegas, Raphael Heinzer, Aleksandra Wierzbicka, Peter Young, Birgit Högl, Claudio L Bassetti, Mauro Manconi, Eva Feketeova, Johannes Mathis, Teresa Paiva, Francesca Canellas, Michel Lecendreux, Christian R Baumann, Lucie Barateau, Carole Pesenti, Elena Antelmi, Carles Gaig, Alex Iranzo, Laura Lillo-Triguero, Pablo Medrano-Martínez, José Haba-Rubio, Corina Gorban, Gianina Luca, Gert Jan Lammers, Ramin Khatami
Narcolepsy is a rare life-long disease that exists in two forms, narcolepsy type-1 (NT1) or type-2 (NT2), but only NT1 is accepted as clearly defined entity. Both types of narcolepsies belong to the group of central hypersomnias (CH), a spectrum of poorly defined diseases with excessive daytime sleepiness as a core feature. Due to the considerable overlap of symptoms and the rarity of the diseases, it is difficult to identify distinct phenotypes of CH. Machine learning (ML) can help to identify phenotypes as it learns to recognize clinical features invisible for humans...
July 13, 2018: Scientific Reports
Bence Varga, Anna Gergely, Ágoston Galambos, Anna Kis
The domestic dog ( Canis familiaris ) has been shown to both excel in recognising human emotions and produce emotion-related vocalisations and postures that humans can easily recognise. However, little is known about the effect of emotional experiences on subsequent sleep physiology, a set of phenomena heavily interrelated with emotions in the case of humans. The present paper examines heart rate (HR) and heart rate variability (HRV) during dogs' sleep, measures that are influenced by both positive and negative emotions in awake dogs...
July 2, 2018: Animals: An Open Access Journal From MDPI
Wei-Long Zheng, Wei Liu, Yifei Lu, Bao-Liang Lu, Andrzej Cichocki
In this paper, we present a multimodal emotion recognition framework called EmotionMeter that combines brain waves and eye movements. To increase the feasibility and wearability of EmotionMeter in real-world applications, we design a six-electrode placement above the ears to collect electroencephalography (EEG) signals. We combine EEG and eye movements for integrating the internal cognitive states and external subconscious behaviors of users to improve the recognition accuracy of EmotionMeter. The experimental results demonstrate that modality fusion with multimodal deep neural networks can significantly enhance the performance compared with a single modality, and the best mean accuracy of 85...
February 8, 2018: IEEE Transactions on Cybernetics
Brianne A Kent, Stephen M Strittmatter, Haakon B Nygaard
BACKGROUND: Sleep disturbances have long been associated with Alzheimer's disease (AD), and there is a growing interest in how these disturbances might impact AD pathophysiology. Despite this growing interest, surprisingly little is known about how sleep architecture and the broader neuronal network are affected in widely used transgenic mouse models of AD. OBJECTIVE: We analyzed sleep and electroencephalography (EEG) power in three transgenic mouse models of AD, using identical and commercially available hardware and analytical software...
2018: Journal of Alzheimer's Disease: JAD
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