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Superior colliculus

A V Revishchin, G M Solus, I I Poletaeva, G V Pavlova
Using immunoblotting, we showed that in rats of audiogenic epilepsy (AE) prone strain (Krushinsky- Molodkina, KM) the superior colliculus tissue (SC) contains significantly less quantity of glial neurotrophic factor (GDNF), beta-tubulin and actin in comparison to the same brain region in "0" rats, nonprone to AE. This fact led to the suggestion that the histological structure of the SC in KM rats could differ significantly from that of the "0" strain. Using neuromorphologу technique, we demonstrated that the total number of SC cells, as well as the number of neurons were significantly less in KM rats than in the "0" strain rats...
January 2018: Doklady. Biochemistry and Biophysics
Alfred Lim, Vivian Eng, Steve M J Janssen, Jason Satel
Inhibition of return (IOR) refers to an increase in reaction times to targets that appeared at a previously cued location relative to an uncued location, often investigated using a spatial cueing paradigm. Despite numerous studies that have examined many aspects of IOR, the neurophysiological mechanisms underlying IOR are still in dispute. The objective of the current research is to investigate the plausible mechanisms by manipulating the cue and target types between central and peripheral stimuli in a traditional cue-target paradigm with saccadic responses to targets...
March 8, 2018: Experimental Brain Research. Experimentelle Hirnforschung. Expérimentation Cérébrale
Lei Li, Xiaolong Feng, Zheng Zhou, Huiqi Zhang, Qianqian Shi, Zhuogui Lei, Peilei Shen, Qingning Yang, Binghao Zhao, Shuran Chen, Lin Li, Yulin Zhang, Pengjie Wen, Zhonghua Lu, Xiang Li, Fuqiang Xu, Liping Wang
Defensive responses to threatening stimuli are crucial to the survival of species. While expression of these responses is considered to be instinctive and unconditional, their magnitude may be affected by environmental and internal factors. The neural circuits underlying this modulation are still largely unknown. In mice, looming-evoked defensive responses are mediated by the superior colliculus (SC), a subcortical sensorimotor integration center. We found that repeated stress caused an anxiety-like state in mice and accelerated defensive responses to looming...
February 26, 2018: Current Biology: CB
Cristiano Cuppini, Barry E Stein, Benjamin A Rowland
The ability to integrate information across its multiple senses enhances the brain's ability to detect, localize, and identify external events. This process has been well-documented in single neurons in the superior colliculus (SC), which synthesize concordant combinations of visual, auditory, and/or somatosensory signals to enhance the vigor of their responses. This increases the physiological salience of cross-modal events and, in turn, the speed and accuracy of SC-mediated behavioral responses to them. However, this capability is not an innate feature of the circuit, and only develops postnatally after the animal acquires sufficient experience with covariant cross-modal events to form links between their modality-specific components...
March 1, 2018: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
Lei Wang, Li-Chuan Yang, Qian-Li Meng, Yuan-Ye Ma
Superior colliculus-pulvinar-amygdala pathway is one of the subcortical visual pathways in mammalian brain. Some recent studies suggest that this pathway is involved in processing emotion-related visual information. This review discusses the possibility that this pathway is more related to visual alert rather than simply the early visual information processing. The biological significance of this pathway is also discussed. Instead of detecting "where" or "what" the visual target is, the task of this early visual stage is to send out a warning signal, i...
February 25, 2018: Sheng Li Xue Bao: [Acta Physiologica Sinica]
Antonela Muca, Emily Standafer, Aaron K Apawu, Farhan Ahmad, Farhad Ghoddoussi, Mirabela Hali, James Warila, Bruce A Berkowitz, Avril Genene Holt
Loud noise frequently results in hyperacusis or hearing loss (i.e., increased or decreased sensitivity to sound). These conditions are often accompanied by tinnitus (ringing in the ears) and changes in spontaneous neuronal activity (SNA). The ability to differentiate the contributions of hyperacusis and hearing loss to neural correlates of tinnitus has yet to be achieved. Towards this purpose, we used a combination of behavior, electrophysiology, and imaging tools to investigate two models of noise-induced tinnitus (either with temporary hearing loss or with permanent hearing loss)...
February 27, 2018: Brain Structure & Function
Shinya Ito, David A Feldheim
The superior colliculus (SC) is a midbrain area where visual, auditory and somatosensory information are integrated to initiate motor commands. The SC plays a central role in visual information processing in the mouse; it receives projections from 85% to 90% of the retinal ganglion cells (RGCs). While the mouse SC has been a long-standing model used to study retinotopic map formation, a number of technological advances in mouse molecular genetic techniques, large-scale physiological recordings and SC-dependent visual behavioral assays have made the mouse an even more ideal model to understand the relationship between circuitry and behavior...
2018: Frontiers in Neural Circuits
Okihide Hikosaka, Hyoung F Kim, Hidetoshi Amita, Masaharu Yasuda, Masaki Isoda, Yoshihisa Tachibana, Atsushi Yoshida
A prominent target of the basal ganglia is the superior colliculus (SC) which controls gaze orientation (saccadic eye movement in primates) to an important object. This 'object choice' is crucial for choosing an action on the object. SC is innervated by the substantia nigra pars reticulata (SNr) which is controlled mainly by the caudate nucleus (CD). This CD-SNr-SC circuit is sensitive to the values of individual objects and facilitates saccades to good objects. The object values are processed differently in two parallel circuits: flexibly by the caudate head (CDh) and stably by the caudate tail (CDt)...
February 23, 2018: European Journal of Neuroscience
João Jorge, Patrícia Figueiredo, Rolf Gruetter, Wietske van der Zwaag
External stimuli and tasks often elicit negative BOLD responses in various brain regions, and growing experimental evidence supports that these phenomena are functionally meaningful. In this work, the high sensitivity available at 7T was explored to map and characterize both positive (PBRs) and negative BOLD responses (NBRs) to visual checkerboard stimulation, occurring in various brain regions within and beyond the visual cortex. Recently-proposed accelerated fMRI techniques were employed for data acquisition, and procedures for exclusion of large draining vein contributions, together with ICA-assisted denoising, were included in the analysis to improve response estimation...
February 20, 2018: Human Brain Mapping
Mary K L Baldwin, Nicole A Young, Denis Matrov, Jon H Kaas
The superior colliculus is an important midbrain structure involved with integrating information from varying sensory modalities and sending motor signals to produce orienting movements toward environmental stimuli. Because of this role, the superior colliculus receives a multitude of sensory inputs from a wide variety of subcortical and cortical structures. Proportionately, the superior colliculus of gray squirrels is among the largest in size of all studied mammals, suggesting the importance of this structure in the behavioral characteristics of gray squirrels...
February 16, 2018: European Journal of Neuroscience
Heywood M Petry, Martha E Bickford
This review provides a historical account of the discovery of secondary visual pathways (from retina to the superior colliculus to the dorsal thalamus and extrastriate cortex), and Vivien Casagrande's pioneering studies of this system using the tree shrew as a model. Subsequent studies of visual pathways in the tree shrew are also reviewed, beginning with a description of the organization and central projections of the tree shrew retina. The organization and connectivity of 2nd visual system components, that include the retino-recipient superior colliculus, tecto-recipient pulvinar nucleus and its projections, and the tecto-recipient dorsal lateral geniculate nucleus and its projections are detailed...
February 15, 2018: Journal of Comparative Neurology
Rebecca B Beck, Eavan M McGovern, John S Butler, Dorina Birsanu, Brendan Quinlivan, Ines Beiser, Shruti Narasimham, Sean O'Riordan, Michael Hutchinson, Richard B Reilly
The temporal discrimination threshold (TDT) is the shortest time interval at which an observer can discriminate two sequential stimuli as being asynchronous (typically 30-50 ms). It has been shown to be abnormal (prolonged) in neurological disorders, including cervical dystonia, a phenotype of adult onset idiopathic isolated focal dystonia. The TDT is a quantitative measure of the ability to perceive rapid changes in the environment and is considered indicative of the behavior of the visual neurons in the superior colliculus, a key node in covert attentional orienting...
January 27, 2018: Journal of Visualized Experiments: JoVE
Kristin Koller, Robert D Rafal, Adam Platt, Nicholas D Mitchell
Probabilistic diffusion tractography was used to provide the first direct evidence for a subcortical pathway from the retina to the amygdala, via the superior colliculus and pulvinar, that transmits visual stimuli signalling threat. A bias to orient toward threat was measured in a temporal order judgement saccade decision task, under monocular viewing, in a group of 19 healthy participants who also underwent diffusion weighted MR imaging. On each trial of the behavioural task a picture depicting threat was presented in one visual field and a competing non-threating stimulus in the other...
February 2, 2018: Neuropsychologia
Amy C Turner, Agata Stramek, Igor Kraev, Michael G Stewart, Paul G Overton, Eleanor J Dommett
Distractibility can be defined as an attention deficit where orientation toward irrelevant targets cannot be inhibited. There is now mounting evidence that the superior colliculus is a key neural correlate of distractibility, with increased collicular-activity resulting in heightened distractibility. Heightened distractibility is reduced by amphetamine, which acutely suppresses collicular responsiveness. However, when amphetamine is used to treat distractibility, it is given chronically, yet no data exist on whether chronic amphetamine treatment affects the colliculus...
January 27, 2018: Behavioural Brain Research
Kristin Koller, Robert D Rafal
The superior colliculus (SC) plays a critical role in mediating reflexive eye movements. Under optimal conditions, for example including a temporal 'gap' of 200 ms after fixation offset and prior to target onset, it is possible to isolate a population of 'express' saccades with very short latencies between (80 - 120 ms). Ablation of the SC abolishes express saccades in monkeys. However, it remains to be established whether express saccade generation is dependent upon visual afferents transmitting direct retinal projections to SC via the retinotectal tract (RTT)...
January 29, 2018: Neuropsychologia
Bahadir Kasap, A John Van Opstal
In dynamic visual or auditory gaze double-steps, a brief target flash or sound burst is presented in midflight of an intervening eye-head gaze shift. Behavioral experiments in humans and monkeys have indicated that the subsequent eye- and head movements to the target are goal-directed, regardless stimulus timing, first gaze-shift characteristics, and initial conditions. This remarkable behavior requires that the gaze-control system (i) has continuous access to accurate signals about eye-in-head position, and ongoing eye-head movements, (ii) that it accounts for different internal signal delays, and (iii) that it is able to update the retinal (TE) and head-centric (TH) target coordinates into appropriate eye-centered and head-centered motor commands on millisecond time scales...
January 31, 2018: Journal of Neurophysiology
Brian Odegaard, Piercesare Grimaldi, Seong Hah Cho, Megan A K Peters, Hakwan Lau, Michele A Basso
Recent studies suggest that neurons in sensorimotor circuits involved in perceptual decision-making also play a role in decision confidence. In these studies, confidence is often considered to be an optimal readout of the probability that a decision is correct. However, the information leading to decision accuracy and the report of confidence often covaried, leaving open the possibility that there are actually two dissociable signal types in the brain: signals that correlate with decision accuracy (optimal confidence) and signals that correlate with subjects' behavioral reports of confidence (subjective confidence)...
January 30, 2018: Proceedings of the National Academy of Sciences of the United States of America
Rafael Coveñas, Arturo Mangas, Manuel Lisardo Sànchez, Diana Cadena, Marianne Husson, Michel Geffard
This review updates the findings about the anatomical distribution (using immunohistochemical techniques) and possible functions of D-glutamate in the central nervous system of mammals, as well as compares the distribution of D-glutamate with the distribution of the most studied D-amino acids: D-serine and D-aspartate. The protocol used to obtain highly specific antisera directed against D-amino acids is also reported. Immunoreactivity for D-glutamate was found in dendrites and cell bodies, but not in nerve fibers...
January 24, 2018: Folia Histochemica et Cytobiologica
Timothy K MacLachlan, Mark N Milton, Oliver Turner, Francis Tukov, Vivian W Choi, Jan Penraat, Marie-Hélène Delmotte, Lydia Michaut, Bruce D Jaffee, Chad E Bigelow
Retinitis pigmentosa is a form of retinal degeneration usually caused by genetic mutations affecting key functional proteins. We have previously demonstrated efficacy in a mouse model of RLBP1 deficiency with a self-complementary AAV8 vector carrying the gene for human RLBP1 under control of a short RLBP1 promoter (CPK850).1 In this article, we describe the nonclinical safety profile of this construct as well as updated efficacy data in the intended clinical formulation. In Rlbp1-/- mice dosed at a range of CPK850 levels, a minimum efficacious dose of 3 × 107 vg in a volume of 1 μL was observed...
March 16, 2018: Molecular Therapy. Methods & Clinical Development
Valeria C Caruso, Daniel S Pages, Marc A Sommer, Jennifer M Groh
We accurately perceive the visual scene despite moving our eyes ~3 times per second, an ability that requires incorporation of eye position and retinal information. In this study, we assessed how this neural computation unfolds across three interconnected structures: frontal eye fields (FEF), intraparietal cortex (LIP/MIP), and the superior colliculus (SC). Single unit activity was assessed in head-restrained monkeys performing visually-guided saccades from different initial fixations. As previously shown, the receptive fields of most LIP/MIP neurons shifted to novel positions on the retina for each eye position, and these locations were not clearly related to each other in either eye- or head-centered coordinates (defined as hybrid coordinates)...
December 20, 2017: Journal of Neurophysiology
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