scholarly journals Photosensitive neurons in mollusks

2005 ◽  
Vol 57 (4) ◽  
pp. 247-258 ◽  
Author(s):  
Gordana Kartelija ◽  
M. Nedeljkovic ◽  
Lidija Radenovic
Keyword(s):  
Dorsal Surface ◽  
Underlying Mechanism ◽  
Nerve Cells ◽  
Induced Response ◽  
Electrophysiological Properties ◽  
Font Color

In addition to regular photoreceptors, some invertebrates possess simple extra ocular photoreceptors. For ex?ample, the central ganglia of mollusks contain photosensitive neurons. These neurons are located on the dorsal surface of the ganglia and based on their electrophysiological properties it has been postulated that they are internal photoreceptors. Besides the eye, transduction of light also occurs in these extra-ocular photoreceptors. In the present work, we analyze the reactivity of these nerve cells to light and describe the underlying mechanism mediating the light-induced response. <br><br><font color="red"><b> This article has been retracted. Link to the retraction <u><a href="http://dx.doi.org/10.2298/ABS150317025E">10.2298/ABS150317025E</a><u></b></font>

scholarly journals Integrating Topographic Measures to Explore the Protective Effects of Peonidin Against the N-Methyl-N-Nitrosourea Induced Photoreceptor Degeneration

2016 ◽  
Vol 38 (3) ◽  
pp. 893-908 ◽  
Author(s):  
Ye Tao ◽  
Tao Chen ◽  
Zhongyu Liu ◽  
Weiwei Xu ◽  
Limin Qin ◽  
...  
Keyword(s):  
Electrode Array ◽  
Visual Signal ◽  
Induced Response ◽  
Signal Pathways ◽  
Protective Effects ◽  
Spontaneous Firing ◽  
Photoreceptor Degeneration ◽  
Electrophysiological Properties ◽  
Beneficial Effects ◽  
Novel Treatment

Background/Aims: The pathphysiological properties of N-Methyl -N -nitrosourea (MNU) induced photoreceptor degeneration are similar to the hereditary retinitis pigmentosa (RP). The present study sought to explore the beneficial effects of the peonidin, a common aglycone form of anthocyanin, on the MNU induced photoreceptor degeneration via topographic measurements. Methods: The MNU administrated mouse received peonidin or vehicle injections, and then they were examined by electroretinography (ERG), multi electrode array (MEA), histological and immunohistochemistry studies. Results: The protective effects of peonidin on the MNU administrated retinas were systematically verified and quantified by topographic measures. The peonidin treatment could protect the photoreceptor against the MNU toxicity both functionally and morphologicaly. The most sensitive zone to peonidin therapy was sorted out, indicating that different rescuing kinetics existed between the retinal hemispheres and retinal quadrants. Moreover, the hyperactive spontaneous firing response and the debilitated light induced response in MNU administrated retinas could be partially reversed by peonidin treatment. To our knowledge, this was the first study to explore the pharmacological effects of peonidin on the electrophysiological properties of inner visual signal pathways. Conclusion: The peonidin could ameliorate the MNU induced photoreceptors degeneration and rectify the abnormities in the inner visual signal pathways. Future refinements of the knowledge cast insights into the discovery of a novel treatment for human RP.

scholarly journals No Effect of Red on Personality Trait Self-Ratings: Testing for Effects of Font Color

2019 ◽  
Vol 5 (1) ◽  
Author(s):  
Daniel Wolf ◽  
Astrid Schütz
Keyword(s):  
Performance Measures ◽  
Personality Trait ◽  
Psychological Functioning ◽  
Underlying Mechanism ◽  
Psychological Research ◽  
Ripe Fruit ◽  
Psychological Theories ◽  
Rigorous Research ◽  
Larger Sample ◽  
Font Color

Unlike most other mammals, humans are trichromats and have the ability to perceive the color red. An explanation for the evolution of humans’ trichromatic color vision is that it offers humans the advantage to detect ripe fruit. Apart from this explanation, psychological theories have proposed that color, especially the color red, conveys information that affects psychological functioning, but results have been mixed. Whereas studies have extensively tested effects of red on performance measures, it is unclear whether this effect generalizes to self-ratings, one of the most frequently used methods in psychological research. In line with theory and empirical evidence, we argue that exposure to red can lead to distorted responses in self-ratings on the basis of the same underlying mechanism that affects results on performance measures. We varied the font color (hue values) of self-ratings in two online studies. In a first exploratory study, we found an effect of font color on personality trait self-ratings (N = 145). We attempted to rigorously replicate this finding in a larger sample (N = 1,007) but did not detect any effect. The findings underline the importance of rigorous research on effects of color on psychological functioning and call into question the proposition that red has ubiquitous effects.

scholarly journals Examining the episodic context account: does retrieval practice enhance memory for context?

2019 ◽  
Vol 4 (1) ◽  
Author(s):  
Min Kyung Hong ◽  
Sean M. Polyn ◽  
Lisa K. Fazio
Keyword(s):  
Retrieval Practice ◽  
Underlying Mechanism ◽  
Initial Study ◽  
Current Theory ◽  
Learning Context ◽  
Prior Learning ◽  
Study Strategy ◽  
Practice Condition ◽  
Study Context ◽  
Font Color

AbstractRetrieval practice, such as filling in blanks or taking quizzes, is firmly established as an effective study strategy. However, the underlying mechanism of how retrieval practice benefits memory is still unclear. One current theory, the episodic context account, proposes that retrieval enhances memory by reinstating a prior learning context. This retrieved context is then strengthened and updated to include context at the time of recall, which later serves as an effective retrieval cue. However, few studies have directly tested this hypothesis. We did so by examining participants’ memory for the initial study context. Across three experiments, participants encoded cue-target pairs presented in different colors and either restudied or practiced retrieving the targets. If retrieval practice benefits memory by reinstating the prior episodic context, participants who successfully retrieved the items during practice should have enhanced memory for context details (i.e. font color) compared to participants who restudied the pairs. Contrary to this prediction, memory for font colors did not differ between the restudy condition and the retrieval practice condition. Even when font color was actively attended to and integrated with the to-be-remembered items, retrieval practice did not increase memory for this aspect of context. Our results suggest that the context reinstated during retrieval practice is limited in nature. Aspects of the context that are not essential to retrieval of the item are not strengthened by retrieval practice.

scholarly journals ABNORMALITIES PRODUCED IN THE CENTRAL NERVOUS SYSTEM BY ELECTRICAL INJURIES

1930 ◽  
Vol 51 (6) ◽  
pp. 943-964 ◽  
Author(s):  
Orthello R. Langworthy
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Dorsal Surface ◽  
Nerve Cells ◽  
Histological Structure ◽  
Dorsal Nucleus ◽  
Different Types ◽  
Group A ◽  
The Central Nervous System ◽  
Circuit Group

The alternating and continuous circuits produced different types of lesions in the central nervous system. Hemorrhages were common after alternating current shocks and few hemorrhages were observed in the continuous circuit group. With both types of circuits at 1000 and 500 volts potential, severe abnormalities in the nerve cells were observed. These were more marked in the continuous circuit group. A uniformly staining, shrunken, pyknotic nucleus was taken as a criterion of nerve cell death. The Purkinje cells of the cerebellum were most susceptible to the current. Injured cells were studied in the dorsal nucleus of the vagus, in the somatic motor group, among the primary sensory neurones and in the olives. Changes in the histological structure of the cells in reference to recovery have been discussed. Injury to the cerebral and cerebellar cortices occurred on the dorsal surface close to the head electrode. Small cavities were produced, particularly in the cerebral cortex, as the result of the circuit contact. With the continuous and alternating circuits at 110 and 220 volts potential less severe changes were observed in the nerve cells although hemorrhages were common in the alternating circuit group. It must be assumed in these cases that death was due to respiratory block rather than actual death of the cells.

Electrophysiological Responses to Light of Neurons in the Eye and Statocyst of Lymnaea stagnalis

2005 ◽  
Vol 93 (1) ◽  
pp. 493-507 ◽  
Author(s):  
Manabu Sakakibara ◽  
Tomoyo Aritaka ◽  
Akira Iizuka ◽  
Hiroyuki Suzuki ◽  
Tetsuro Horikoshi ◽  
...  
Keyword(s):  
T Cells ◽  
Response Latency ◽  
Hair Cells ◽  
Lymnaea Stagnalis ◽  
Light Flash ◽  
Sensory Information ◽  
Cerebral Ganglion ◽  
Induced Response ◽  
Electrophysiological Properties ◽  
Electrophysiological Responses

Lymnaea can be classically conditioned by pairing photic stimulation with a rotational stimulus. The electrophysiological properties of the Lymnaea photoreceptors and statocyst neurons are incompletely known. There are 2 types of ocular photoreceptors and 3 types of statocyst “hair cells.” Type A photoreceptors had a response latency from 200 to 400 ms, with a graded depolarizing response having maximum action spectra at 480–500 nm, corresponding to the βmax of rhodopsin. Additionally they extend their axons in the direction of the other type of photoreceptor neuron, the type T cell. These neurons have a 2-component response to light: a response reversibly reduced in Ca2+-free saline, and a component persisting in Ca2+-free saline. Type T cells send processes into the cerebral ganglion and terminate close to the ending of the statocyst hair cells. Hair cells send their terminal branches to the cerebral ganglia close to the terminations of the type T cells. Caudal hair cells respond to a light flash with a depolarization, whereas the rostral cells respond with a hyperpolarization. The response latency in all hair cells was dependent on the stimulus intensity; the brightest light tested had a latency of 200 ms. The photo-induced response was abolished in Ca2+-free saline, whereas it was still present in high Ca2+–high Mg2+ saline, consistent with the hypothesis that the connection between the photoreceptors and hair cells is monosynaptic. Thus the sensory information necessary for forming an association between photic and rotational stimuli converges on the statocyst neurons.

Study on Hodgkin-Huxley Neuron Model under Disturbance

2013 ◽  
Vol 411-414 ◽  
pp. 3261-3264
Author(s):  
Xiao Yu Chen ◽  
Lin Wang ◽  
Ying Jie Wang ◽  
Xiao Qiang Liang
Keyword(s):  
Electric Field ◽  
Action Potentials ◽  
Quantitative Description ◽  
Biological Rhythms ◽  
Nerve Cells ◽  
The Body ◽  
Electromagnetic Environment ◽  
Electrophysiological Properties ◽  
Response Characteristics ◽  
Field Coupling

Nerve cells can respond to external electromagnetic environment. It features mainly depends on the characteristics of the interference conditions. Hodgkin - Huxley (HH) model gives a quantitative description of neuronal action potentials, many electrophysiological properties of nerve cells and biological rhythms issues of interpretation, the nervous system in order to study the effect of noise, this paper considers the environment in result of the presence of the electric field coupling, and the electric field in the body of the response characteristics of HH model, given values of the simulation results and analysis of the effect of disturbance characteristics of neurons as a disturbance conditions neuronal activity.

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