RU2364314C1 - Human visual system recovery time test - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: person under testing observes a sequence of pair light pulses of specified length 20, 40, 60, 80, 100, 120, 140, 160, 180, 200, 220, 240, 260 and 280 ms with pulse separation 150 ms repeating over constant time interval 1 s. In each light pulse length at the first stage of measurements, the pulse separation duration is decreased discretely at specified constant pitch 0.4 ms until a person under testing defines a moment of subjective fusion of two light pulses in pair. At the second stage of measurements, the pulse separation duration is increased discretely at specified constant pitch 0.2 ms, until a person under testing defines a moment of subjective sensation of separability of two light pulses in pair. At the third stage of measurements, the pulse separation duration is decreased discretely at specified constant pitch 0.1 ms until a person under testing defines a moment of subjective fusion of two light pulses in pair. The light pulse separation duration in pair steam at a time is taken as a threshold pulse separation duration t_thres, with function graphing t_thres=f(τ_pulse), where τ_pulse is the light pulse length. A plateau egress point is detected; human visual system recovery time is taken as equal to the threshold pulse separation in the plateau egress point.

EFFECT: human visual analyser recovery time testing.

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Description

The invention relates to medicine and medical equipment and is intended to determine the recovery time of the human visual system.

A known method for determining the duration of the photochemical processes in the receptors of the human retina, based on the assessment of differences in the latent period of a simple sensorimotor reaction of the test subject to adequate (diffuse flash of light) and inadequate (electrical stimulation - "phosphenes") light stimuli. Before the start of the experiments, adequate and inadequate light stimuli are aligned according to “subjective brightness” [1].

A known method of neurophysiological studies of the temporal processing of signals in the striatal cortex of animals. The experiments carried out by this method established the appearance of a detected receptive field in different neurons 20-80 ms after the light stimulus was turned on, the maximum reaction of the receptive field was found in 60-100 ms, and its disappearance in 100-200 ms [2]. According to this method, animals were anesthetized, immobilized, artificially ventilated and thermally stabilized. Registration of the receptive field was performed using an electroencephalogram.

The disadvantage of this method is the long preparatory period before conducting research, the inability to determine the recovery time of the human visual system.

A known method for determining the excitation time of a human visual analyzer is that a subject is presented with a sequence of paired light pulses of a given duration equal to 200 ms, separated by an interpulse interval of 70 ms, repeated through a constant time interval of 1 s, and at the first stage of measurements, the duration of the interpulse the interval between light pulses in a pair is reduced at a given constant speed of 20 ms / s, until the subject determines the moment of subjective fusion of two pair of wind pulses in one, at the second measurement stage, the duration of the inter-pulse interval between light pulses in a pair is increased at a given constant speed of 2 ms / s, until the subject determines the moment of subjective sensation of the separation of two light pulses in a pair, at the third measurement stage, the duration of the inter-pulse interval between light pulses in a pair is reduced discretely with a given constant step of 0.1 ms until the subject determines the moment of subjective merging of two light pulses in a pair into one, in emya excitation optic value analyzer shall be equal to the pulse interval duration, a certain test measurements in the third step [3].

The closest in technical essence to the proposed method is a method for determining the lability of the human visual system [4], which consists in the fact that the subject is presented with a sequence of paired light pulses of a given duration equal to 110, 90, 70, 50, 30, 10, 5, 1, respectively ms, separated by an interpulse interval of 150 ms, repeated through a constant time interval of 1 s, in which for each given duration of light pulses in the first measurement stage, the duration of the interpulse interval is reduced They are discrete with a predetermined constant step of 0.4 ms until the subject determines the moment of subjective fusion of two light pulses in a pair into one, at the second measurement stage, the duration of the interpulse interval is increased discretely with a predetermined constant step of 0.2 ms, until the subject determines the moment of subjective sensations of separation of two light pulses in a pair, at the third stage of measurements, the duration of the interpulse interval is reduced discretely with a given constant step of 0.1 ms, until the subject determines the moment of subjective fusion of two optical pulses in one pair, and the duration of the pulse interval between light pulses in a pair at a time taken for the duration of the pulse interval threshold, calculating time perception of visual information

t _take = τ _imp + t _then

where τ _imp - the duration of the light pulse; t _pop - threshold duration of the interpulse interval between light pulses in a pair, plot the function

t _take = f (τ _imp ),

find the minimum of the function, the lability of the human visual system is taken equal to the frequency value in Hz at the minimum point of the function

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The disadvantage of this method is the inability to determine the recovery time of the human visual analyzer.

The technical result of the proposed method lies in the possibility of determining the recovery time of the human visual analyzer.

The technical result is achieved by the fact that the test subject is presented with a sequence of pair of light pulses of a given duration, separated by an interpulse interval of 150 ms, repeated through a constant time interval of 1 s; for each given duration of light pulses at the first stage of measurements, the duration of the interpulse interval is reduced discretely with a given constant step of 0.4 ms, until the subject determines the moment of subjective fusion of two light pulses in a pair into one; at the second stage of measurements, the duration of the interpulse interval is increased discretely with a given constant step of 0.2 ms, until the subject determines the moment of subjective sensation of the separation of two light pulses in a pair; at the third stage of measurements, the duration of the interpulse interval is reduced discretely with a given constant step of 0.1 ms, until the subject determines the moment of subjective merging of two light pulses in a pair into one, the duration of the interpulse interval between light pulses in a pair at a given time is taken as the threshold duration of the interpulse interval t _pop , and new is that the duration of the light pulse in a pair is set equal to 20, 40, 60, 80, 100, 120, 140, 160, 180, 200, 220, 240, 260, and 280 ms, and a function is plotted

t _then = f (τ _imp ),

where τ _imp - the duration of the light pulse, find the exit point of the graph on the plateau; the recovery time of the human visual system is taken equal to the value of the threshold interpulse interval at the point where the graph reaches a plateau.

The proposed method for determining the recovery time of the human visual system is as follows.

Figure 1 presents a timing diagram of a sequence of paired light pulses presented to determine the recovery time of the human visual system, where:

t _NMI - the initial duration of the interpulse interval;

T is a constant time interval for the repetition of pairs of light pulses;

τ _imp - the duration of the light pulse.

Figure 2 presents the timing diagram of the change in the duration of the interpulse interval between light pulses in a pair when determining the recovery time of the human visual system.

Figure 3 presents the timing diagrams of two light pulses of duration τ _imp , separated by the interpulse interval t of the _mission , and the visual sensations caused by them, where:

Fig. 3a is a timing diagram of two light pulses separated by an interpulse interval t of a _mission , causing a visual sensation of separation of pulses;

figb - time diagram of the visual sensation of the two light pulses shown in figa;

figv is a timing diagram of two light pulses separated by a threshold interpulse interval t _pop , at which a subjective sensation of fusion of two light pulses in a pair into one is achieved;

figg - time diagram of the visual sensation of the two light pulses shown in figv;

τ ₁ - the time of visual sensation, the time between the moment of exposure of light to the retina and the moment of occurrence of the corresponding visual sensation [5, 6];

τ ₂ is the recovery time, the time between the moment the light stops affecting the retina and the moment the corresponding visual sensation disappears [5, 6].

Figure 4 presents a graph of the function t _pop = f (τ _imp ), constructed according to measurements of the threshold duration of the _inter -pulse interval t _pop for various light pulses τ _imp .

The test subject is presented with a sequence of pair of light pulses of a given duration τ _imp equal to 20 ms, separated by an interpulse interval of the initial duration t _nm equal to 150 ms, repeated through a constant time interval T equal to 1 s (Fig. 1; Fig. 2, time interval T ₀ -T ₁ ).

The duration of the inter-pulse interval between light pulses in a pair is reduced until the subject determines the moment of subjective fusion of two light pulses in a pair into one.

At the first stage of the measurements, the initial duration of the _inter -pulse interval t of the _pulse between the light pulses in a pair is reduced discretely with a given constant step of 0.4 ms (Fig. 2, the time interval T ₁ -T ₃ ) until the subject determines the moment of subjective fusion of two light pulses in a pair of one (figure 2, time point T ₃ ).

At the second measurement stage, the duration of the interpulse interval t of the _mission between the light pulses in a pair is increased discretely with a predetermined constant step of 0.2 ms (Fig. 2, the time interval T ₄ -T ₆ ), until the subject determines the moment of subjective sensation of the separation of two light pulses in a pair (figure 2, time point T ₆ ).

At the third stage of measurements, the duration of the inter-pulse interval t of the _mission between the light pulses in a pair is reduced discretely with a given constant step of 0.1 ms (Fig. 2, the time interval T ₇ -T ₈ ) until the subject determines the moment of subjective fusion of two light pulses in a pair in one (figure 2, time point T ₈ ). The duration of the interpulse interval t of the _mission between the light pulses in the pair at time T _{8 is} taken as the threshold duration of the interpulse interval t _pop .

The threshold duration of the interpulse interval t _then is determined similarly for light pulses of 40, 60, 80, 100, 120, 140, 160, 180, 200, 220, 240, 260, and 280 ms.

Based on the measured values of the threshold duration of the interpulse interval t _pop obtained at different light pulse durations τ _imp , a graph of the function

t _pop = f (τ _imp ),

where τ _imp is the duration of the light pulse at which the exit point to the plateau is found (horizontal part of the graph).

The recovery time of the human visual system is taken equal to the value of the threshold interpulse interval at the point where the graph reaches a plateau.

The initial duration of the _inter -pulse interval t _{nm was} selected according to the analysis of the development of receptive fields (RP) of neurons. Since the disappearance of RP occurs 100–200 ms after the presentation of the light stimulus [2], two light pulses will be felt separate if the second light pulse is presented 100–200 ms after the start of the presentation of the first light pulse. Therefore, the initial duration of the _inter -pulse interval t _{NMI is} chosen equal to 150 ms.

It is known that the perception of a visual stimulus is hampered under the conditions of reverse masking, which consists in the deterioration of the perception of the first time stimulus due to the presentation of the second stimulus in the immediate spatio-temporal proximity to the first. It has been shown that there is not only a reverse effect, but also direct masking, in which the first stimulus affects the quality of perception of the second [7]. At an interstimulus interval of 500 ms, masking effects are absent or weakly expressed [8]. To eliminate the masking effect, the sequence of paired light pulses is repeated at a constant time interval of 1 s.

Upon presenting to the subject two light pulses of duration τ _imp > τ ₁ separated by an interpulse interval t _mission > t _pop ( _Fig.3a ), he experiences a subjective sensation of separation of two light pulses (Fig.3b). When reducing the duration of the interpulse interval t of the _mission between two light pulses to a value of t _mission = t _pop (Fig.3c), the subject has a feeling of subjective merging of two light pulses into one (Fig.3d).

Since the RP of a neuron when the light stimulus is turned on after it reaches its maximum and then disappears [2], then after the maximum of its reaction recovery processes begin, functional disorganization of the RP occurs, the neural structures return to their initial “zero” state and become ready for a new cycle of visual perception incentives [9].

With a large duration of the light pulse, the duration of the threshold interpulse interval does not depend on the duration of the light pulse (Fig. 4), that is, the time required to restore the visual system remains constant. With a decrease in the duration of the light pulse to a certain value, the duration of the threshold interpulse interval begins to increase (Fig. 4). This is due to the onset of masking, which causes an increase in the time required to restore the visual system.

Thus, the inventive method allows to determine the recovery time of the human visual system by the value of the threshold interpulse interval at the exit point of the graph of the function t _pop = f (τ _imp ) to the plateau, that is, it has new properties that determine the receipt of a positive effect.

Example. Subject K., 19 years old, using a personal computer that emits light pulses through the LPT port on the indicator of the subject's remote control, showed a sequence of paired light pulses of duration τ _imp equal to 20 ms, separated by an initial interpulse interval of duration t _nm , equal to 150 ms, repeated through a constant time interval T equal to 1 s (figure 1; figure 2, the time interval T ₀ -T ₁ ).

In the process of measurement through the LPT port, the signals from the buttons “Decrease 0.4 ms”, “Increase 0.2 ms”, “Decrease 0.1 ms” and “Measurement” were sent to the personal computer from the test person’s remote control.

When a signal is received from the “Decrease 0.4 ms” button, the computer discretely reduced the duration of the inter-pulse interval between light pulses paired with a constant step of 0.4 ms, and when a signal is received from the “Increase 0.2 ms” button, it discretely increased with a constant step of 0 , 2 ms, upon receipt of a signal from the button “Decrease 0.1 ms” - discretely reduced with a constant step of 0.1 ms.

At the first stage, the test subject, giving a signal from the button “Decrease 0.4 ms” (figure 2, the time interval T ₁ -T ₃ ), determined the moment of subjective fusion of two light pulses in a pair into one (figure 2, time moment T ₃ )

At the second stage, the test subject, giving a signal from the button “Increase 0.2 ms” (figure 2, the time interval T ₄ -T ₆ ), determined the moment of subjective sensation of the separation of two light pulses in a pair (figure 2, time T ₆ ) .

At the third stage, the test subject, giving a signal from the button “Decrease 0.1 ms” (figure 2, the time interval T ₇ -T ₈ ), determined the moment of subjective fusion of two light pulses in a pair into one (figure 2, time point T ₈ ), then gave the signal from the "Measurement" button (Fig. 3, time point T ₉ ).

The computer recorded the duration of the threshold interpulse interval between light pulses in a pair equal to 34.8 ms, taken equal to the recovery time of the human visual system, displayed this value on the monitor screen, entered the measurement result into the archive, and presented the initial sequence of paired light pulses.

In accordance with the recommendations of physiologists, the subject performed a series of 10 measurements. As a result of measurements, the following values of the recovery time of the visual system of the person tested in ms were obtained: 34.8; 35.6; 37.0; 35.3; 37.4; 37.6; 36.7; 36.0; 36.2; 35.4. The arithmetic average of the measured values of the recovery time of the human visual system is 36.2 ms.

Similarly, the subject performed measurements of the recovery time of the human visual system with light pulse durations of 40, 60, 80, 100, 120, 140, 160, 180, 200, 220, 240, 260, and 280 ms.

The results of statistical processing of measurement data are given in the table.

Table The duration of the light pulse, ms twenty 40 60 80 one hundred 120 140 The arithmetic mean of the duration of the threshold interpulse interval, ms 36,2 26.6 20,0 16.7 14.5 12.8 11.3 The duration of the light pulse, ms 160 180 200 220 240 260 280 The arithmetic mean of the duration of the threshold interpulse interval, ms 10,4 10 10 10 10 10 10

Based on the measured values of the duration of the threshold interpulse interval for various durations of light pulses, a function graph is constructed

t _pop = f (τ _imp ), presented in figure 4. On the function graph, the exit point of the graph to the plateau is found, which corresponds to the duration of the threshold interpulse interval, equal to 180 ms, taken as the time of restoration of the human visual system.

Thus, the proposed method allows to determine the recovery time of the human visual system

Information sources

1. Bucik Yalentin. An attempt at determination of the chemical processing time in retina by subjective equalization of stimulus intensity // Rev. psihol. - 1990. - V.20, No. 1-2. - R.11-17.

2. Shevelev I.A. Temporary signal processing in the visual cortex // Human Physiology. - 1997. - T.23, No. 2, S.68-79.

3. RF patent 2231293, A61B 5/16. The method of determining the time of excitation of the visual analyzer of a person / V.V. Rozhentsov, M.T.Aliyev (RF). - Publ. 06/27/2004, Bull. Number 18.

4. Patent 2233115 of the Russian Federation, A61B 5/16. A method for determining the lability of the human visual system / O.V. Rozhentsov, I.V. Petukhov (RF). - Publ. July 27, 2004, Bull. No. 21.

5. Kravkov S.V. Eye and his work. Psychophysiology of vision, lighting hygiene. - 4th ed., Revised. and add. - M.-L.: Publishing House of the Academy of Sciences of the USSR, 1950 .-- 531 p.

6. Semenovskaya E.N. Electrophysiological studies in ophthalmology. - M .: Medgiz, 1963 .-- 279 p.

7. Kropotov Yu.D., Ponomarev V.A. The reaction of neurons and evoked potentials in the subcortical structures of the brain during visual recognition. Message IV. The effect of masking visual stimuli // Human physiology. - 1987. - T.13, No. 4. - S. 561-566.

8. Taroyan N.A., Myamlin V.V., Genkina O.A. Interhemispheric functional relations in the process of solving a visual-spatial problem by a person // Human Physiology. - 1992. - T.18, No. 2. - S. 5-14.

9. Podvigin N.F., Makarov F.N., Shelepin Yu.E. Elements of the structural and functional organization of the visual-oculomotor system. - L .: Nauka, 1986 .-- 252 p.

Claims (1)

The method for determining the recovery time of the human visual system, which consists in the fact that the subject is presented with a sequence of paired light pulses of a given duration, separated by an interpulse interval of 15 ms, repeated through a constant time interval of 1 s; for each given duration of light pulses at the first stage of measurements, the duration of the interpulse interval is reduced discretely with a given constant step of 0.4 ms, until the subject determines the moment of subjective fusion of two light pulses in a pair into one; at the second measurement stage, the duration of the inter-pulse interval is increased discretely with a predetermined constant step of 0.2 ms, until the subject determines the moment of subjective sensation of the separation of two light pulses in a pair; at the third stage of measurements, the duration of the interpulse interval is reduced discretely with a given constant step of 0.1 ms, until the subject determines the moment of subjective merging of two light pulses in a pair into one, the duration of the interpulse interval between light pulses in a pair at a given time is taken as the threshold duration of the interpulse interval t _then , characterized in that the duration of the light pulse in the pair is set equal to 20, 40, 60, 80, 100, 120, 140, 160, 180, 200, 220, 240, 260 and 280 ms, build a graph of the function t _then = f (τ _{imp), and} where τ _n - the duration of the light pulse are generated at the exit point a plateau; the recovery time of the human visual system is taken equal to the value of the threshold interpulse interval at the point of the graph's exit to the plateau.

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