scholarly journals Electrophysiology of the Insect Dorsal Ocellus

1961 ◽  
Vol 44 (3) ◽  
pp. 641-657 ◽  
Author(s):  
Philip Ruck

The ERG of the dragonfly ocellus has been analyzed into four components, two of which originate in the photoreceptor cells, two in the ocellar nerve fibers (Ruck, 1961 a). Component 1 is a sensory generator potential, component 2 a response of the receptor axons. Component 3 is an inhibitory postsynaptic potential, component 4, a discharge of afferent nerve impulses in ocellar nerve fibers. Responses to flickering light are examined in terms of this analytic scheme. It has been found that the generator potential can respond to higher rates of flicker—up to 220/sec.—than can the receptor axon responses, the postsynaptic potential, or the ocellar nerve impulses. The maximum flicker fusion frequency as measured by fusion of the ERG is that of the sensory generator potential itself.

1961 ◽  
Vol 44 (3) ◽  
pp. 605-627 ◽  
Author(s):  
Philip Ruck

Dorsal ocelli are small cup-like organs containing a layer of photoreceptor cells, the short axons of which synapse at the base of the cup with dendritic terminals of ocellar nerve fibers. The ocellar ERG of dragonflies, recorded from the surface of the receptor cell layer and from the long lateral ocellar nerve, contains four components. Component 1 is a depolarizing sensory generator potential which originates in the distal ends of the receptor cells and evokes component 2. Component 2 is believed to be a depolarizing response of the receptor axons. It evokes a hyperpolarizing postsynaptic potential, component 3, which originates in the dendritic terminals of the ocellar nerve fibers. Ocellar nerve fibers in dragonflies are spontaneously active, discharging afferent nerve impulses (component 4) in the dark-adapted state. Component 3 inhibits this discharge. The ERG of the cockroach ocellus is similar. The main differences are that component 3 is not as conspicuous as in the dragonflies and that in most cases ocellar nerve impulses appear only as a brief burst at "off." In one preparation a spontaneous discharge of nerve impulses was observed. As in the dragonflies, this was inhibited by illumination.


1952 ◽  
Vol 32 (3) ◽  
pp. 349-378 ◽  
Author(s):  
Ernst Simonson ◽  
Josef Brozek

Medicina ◽  
2021 ◽  
Vol 57 (10) ◽  
pp. 1096
Author(s):  
Natalia D. Mankowska ◽  
Anna B. Marcinkowska ◽  
Monika Waskow ◽  
Rita I. Sharma ◽  
Jacek Kot ◽  
...  

This review presents the current knowledge of the usage of critical flicker fusion frequency (CFF) in human and animal model studies. CFF has a wide application in different fields, especially as an indicator of cortical arousal and visual processing. In medicine, CFF may be helpful for diagnostic purposes, for example in epilepsy or minimal hepatic encephalopathy. Given the environmental studies and a limited number of other methods, it is applicable in diving and hyperbaric medicine. Current research also shows the relationship between CFF and other electrophysiological methods, such as electroencephalography. The human eye can detect flicker at 50–90 Hz but reports are showing the possibility to distinguish between steady and modulated light up to 500 Hz. Future research with the use of CFF is needed to better understand its utility and application.


2019 ◽  
Vol 98 (12) ◽  
pp. 1402-1407
Author(s):  
Vladislav R. Kuchma ◽  
S. V. Sankov ◽  
N. K. Barsukova

Introduction. Currently, in connection with the large-scale introduction of the electronic educational resource in the educational process, it is especially relevant to search for optimal characteristics of presenting information on screens, taking into account the specifics of the electronic devices and age-related physiological features of the users’ visual system. The aim of the study was a physiological hygienic assessment of the impact of the font design of e-texts, presented on a laptop, on the psychophysiological state of students in grades 10-11. Material and methods. Psychophysiological testing of 43 schoolchildren in grades 10-11 without pathology of the vision organ was carried out on the NS-Psychotest complex, including the method of critical flicker fusion frequency to assess the state of the central part of the visual analyzer and the response to a moving object to determine the degree of the balance in nervous processes. The influence of reading illogical texts typed by a school headset was studied with a font size of 14, 12 and 10 points and a one-time reading of 200, 400 and 600 characters. Laptop Lenovo IdeaPad 720S-15 was used for the presentation of information. Results. High-grade schoolchildren were established to have the initial fatigue both of the visual analyzer and the nervous system as a whole. Boys showed better indices of the critical flicker fusion frequency than girls. Most schoolchildren had a balanced type of the inhibition and excitement processes. Methods of presenting information in electronic textbooks were shown to affect the psychophysiological state of high schoolchildren and may carry risks to their health. The hygienically rational design of electronic educational texts promotes the optimization of the psycho-functional state of the high schoolchildren’s body. Conclusion. The obtained results allow substantiating hygienic requirements for the font design of e-learning publications at the third stage of education.


2021 ◽  
Vol 51 (2) ◽  
pp. 228-229
Author(s):  
Xavier CE Vrijdag ◽  
◽  
Hanna van Waart ◽  
Jamie W Sleigh ◽  
Simon J Mitchell ◽  
...  

2012 ◽  
Vol 62 ◽  
pp. 125-133 ◽  
Author(s):  
Thomas J. Lisney ◽  
Björn Ekesten ◽  
Ragnar Tauson ◽  
Olle Håstad ◽  
Anders Ödeen

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