Selection on quantitative colour variation in Centaurea cyanus : the role of the pollinator's visual system

2013 ◽  
Vol 26 (11) ◽  
pp. 2415-2427 ◽  
Author(s):  
J. P. Renoult ◽  
M. Thomann ◽  
H. M. Schaefer ◽  
P.-O. Cheptou
Keyword(s):  
Visual System ◽  
Colour Variation ◽  
Centaurea Cyanus

Expression of the BDNF gene in the developing visual system of the chick

Development ◽  
1994 ◽  
Vol 120 (6) ◽  
pp. 1643-1649 ◽  
Author(s):  
K.H. Herzog ◽  
K. Bailey ◽  
Y.A. Barde
Keyword(s):  
Visual System ◽  
Ganglion Cells ◽  
Mrna Levels ◽  
Retinal Ganglion ◽  
Bdnf Gene ◽  
Bdnf Mrna ◽  
Optic Stalk ◽  
Copy Numbers ◽  
Activity Dependent

Using a sensitive and quantitative method, the mRNA levels of brain-derived neurotrophic factor (BDNF) were determined during the development of the chick visual system. Low copy numbers were detected, and BDNF was found to be expressed in the optic tectum already 2 days before the arrival of the first retinal ganglion cell axons, suggesting an early role of BDNF in tectal development. After the beginning of tectal innervation, BDNF mRNA levels markedly increased, and optic stalk transection at day 4 (which prevents subsequent tectal innervation) was found to reduce the contralateral tectal levels of BDNF mRNA. Comparable reductions were obtained after injection of tetrodotoxin into one eye, indicating that, already during the earliest stages of target encounter in the CNS, the degree of BDNF gene expression is influenced by activity-dependent mechanisms. BDNF mRNA was also detected in the retina itself and at levels comparable to those found in the tectum. Together with previous findings indicating that BDNF prevents the death of cultured chick retinal ganglion cells, these results support the idea that the tightly controlled expression of the BDNF gene might be important in the co-ordinated development of the visual system.

The role of vision on postural strategy evaluated in patients affected by congenital nystagmus as an experimental model

1999 ◽  
Vol 9 (6) ◽  
pp. 445-451
Author(s):  
S. Di Girolamo ◽  
W. Di Nardo ◽  
A. Cosenza ◽  
F. Ottaviani ◽  
A. Dickmann ◽  
...  
Keyword(s):  
Visual System ◽  
Postural Control ◽  
Visual Stimulus ◽  
Postural Balance ◽  
Visual Cues ◽  
Normal Subjects ◽  
Congenital Nystagmus ◽  
Dynamic Posturography ◽  
Normal Controls

The role of vision in postural control is crucial and is strictly related to the characteristics of the visual stimulus and to the performance of the visual system. The purpose of this investigation was to evaluate the effects of chronically reduced visual cues upon postural control in patients affected by Congenital Nystagmus (CN). These patients have developed since birth a postural strategy mainly based on vestibular and somatosensorial cues. Fifteen patients affected by CN and 15 normal controls (NC) were enrolled in the study and evaluated by means of dynamic posturography. The overall postural control in CN patients was impaired as demonstrated by the equilibrium score and by the changes of the postural strategy. This impairment was even more enhanced in CN than in NC group when somatosensorial cues were experimentally reduced. An aspecific pattern of visual impairment and a pathological composite score were also present. Our data outline that in patients affected by CN an impairment of the postural balance is present especially when the postural control relies mainly on visual cues. Moreover, a decrease in accuracy of the somatosensory cues has a proportionally greater effect on balance than it has on normal subjects.

scholarly journals The Role of Activity in Development of the Visual System

2002 ◽  
Vol 12 (23) ◽  
pp. R818-R826 ◽  
Author(s):  
Frank Sengpiel ◽  
Peter C. Kind
Keyword(s):  
Visual System

Visual Systems and the Role of Vision in Subterranean Rodents: Diversity of Retinal Properties and Visual System Designs

2007 ◽  
pp. 129-160 ◽  
Author(s):  
Pavel Němec ◽  
Pavla Cveková ◽  
Hynek Burda ◽  
Oldřich Benada ◽  
Leo Peichl
Keyword(s):  
Visual System ◽  
Subterranean Rodents ◽  
Visual Systems ◽  
System Designs

scholarly journals A neurodevelopmental origin of behavioral individuality in the Drosophila visual system

Science ◽  
2020 ◽  
Vol 367 (6482) ◽  
pp. 1112-1119 ◽  
Author(s):  
Gerit Arne Linneweber ◽  
Maheva Andriatsilavo ◽  
Suchetana Bias Dutta ◽  
Mercedes Bengochea ◽  
Liz Hellbruegge ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Visual System ◽  
Brain Development ◽  
Interindividual Variation ◽  
Visual Object ◽  
Stochastic Variation ◽  
Behavioral Variation ◽  
The Individual ◽  
And Behavior

The genome versus experience dichotomy has dominated understanding of behavioral individuality. By contrast, the role of nonheritable noise during brain development in behavioral variation is understudied. Using Drosophila melanogaster, we demonstrate a link between stochastic variation in brain wiring and behavioral individuality. A visual system circuit called the dorsal cluster neurons (DCN) shows nonheritable, interindividual variation in right/left wiring asymmetry and controls object orientation in freely walking flies. We show that DCN wiring asymmetry instructs an individual’s object responses: The greater the asymmetry, the better the individual orients toward a visual object. Silencing DCNs abolishes correlations between anatomy and behavior, whereas inducing DCN asymmetry suffices to improve object responses.

Coding Principles in Adaptation

2019 ◽  
Vol 5 (1) ◽  
pp. 427-449 ◽  
Author(s):  
Alison I. Weber ◽  
Kamesh Krishnamurthy ◽  
Adrienne L. Fairhall
Keyword(s):  
Nervous System ◽  
Visual System ◽  
Functional Role ◽  
Receptive Fields ◽  
Sensory Systems ◽  
Spike Frequency Adaptation ◽  
Theoretical Frameworks ◽  
Different Types ◽  
Common Principle

Adaptation is a common principle that recurs throughout the nervous system at all stages of processing. This principle manifests in a variety of phenomena, from spike frequency adaptation, to apparent changes in receptive fields with changes in stimulus statistics, to enhanced responses to unexpected stimuli. The ubiquity of adaptation leads naturally to the question: What purpose do these different types of adaptation serve? A diverse set of theories, often highly overlapping, has been proposed to explain the functional role of adaptive phenomena. In this review, we discuss several of these theoretical frameworks, highlighting relationships among them and clarifying distinctions. We summarize observations of the varied manifestations of adaptation, particularly as they relate to these theoretical frameworks, focusing throughout on the visual system and making connections to other sensory systems.

scholarly journals Possible role of biochemiluminescent photons for lysergic acid diethylamide (LSD)-induced phosphenes and visual hallucinations

2017 ◽  
Vol 28 (1) ◽  
pp. 77-86 ◽  
Author(s):  
Gábor Kapócs ◽  
Felix Scholkmann ◽  
Vahid Salari ◽  
Noémi Császár ◽  
Henrik Szőke ◽  
...  
Keyword(s):  
Visual System ◽  
Lysergic Acid ◽  
Healthy People ◽  
Lysergic Acid Diethylamide ◽  
Visual Hallucinations ◽  
Interest In Research ◽  
The Brain

AbstractToday, there is an increased interest in research on lysergic acid diethylamide (LSD) because it may offer new opportunities in psychotherapy under controlled settings. The more we know about how a drug works in the brain, the more opportunities there will be to exploit it in medicine. Here, based on our previously published papers and investigations, we suggest that LSD-induced visual hallucinations/phosphenes may be due to the transient enhancement of bioluminescent photons in the early retinotopic visual system in blind as well as healthy people.

Does Integration Produce Masking or Protect from it?

Perception ◽  
1981 ◽  
Vol 10 (1) ◽  
pp. 71-83 ◽  
Author(s):  
David Navon ◽  
Dean Purcell
Keyword(s):  
Visual System ◽  
Detrimental Effect ◽  
Facilitatory Effect ◽  
Target Area ◽  
Disruptive Effect ◽  
Type B ◽  
Visual Resolution ◽  
Pattern Masking

To examine the role of integration in pattern masking, possible disruptive effects of integration were minimized by using a mask that overlaid completely all targets. Exposure durations were 10 ms, so under energy summation the target area was much darker than the rest. In another condition the mask was red and targets were blue, so under energy summation the target area could also be distinguished by hue. Masking magnitude increased with delay of mask onset, and it was established by four independent criteria that integration was negligible in the condition which produced most masking. It is deduced that integration is not necessary for masking; furthermore it is suggested that integration never produces masking, but rather may or may not protect from a disruptive effect of interruption. The argument is that were the visual system to have better visual resolution, it would suffer more given the same masking parameters. It is argued that type B masking functions arise from a combination of the facilitatory effect of integration and the detrimental effect of interruption.

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