RU2314032C1 - Device for studying time of inertia of human visual system - Google Patents

Abstract

FIELD: medical equipment.

SUBSTANCE: device has second pulse oscillator, millisecond pulse oscillator, first single-pulse vibrator, second single-pulse vibrator with adjustable pulse duration, third single-pulse vibrator, AND gate, OR gate, control board, counter, first light source, second light source and indication unit. Time of inertia of visual system is studied at simultaneous demonstration of two light pulses during shorter period time, which helps to reduce tiredness of visual system.

EFFECT: simple design; improved efficiency.

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Description

The invention relates to medicine and is intended to study the time of inertia of the human visual system.

A device for the experimental study of the time of inertia of the visual system containing a pendulum that sets the exposure time of the brand and a set of contrast filters [1]. On this device, the threshold contrast e is measured for an object during stationary observation, then, at different contrasts K _n created by a given set of filters, the effective contrast K _{e is} brought to the visibility threshold by selecting the exposure time t defined by the swing amplitude of the pendulum. For the time of inertia of the visual system, the effective time of preservation of the visual impression is taken and when the exposure time t <0.01, it is determined by the formula:

q = K _n t / e.

The disadvantages of the device are its complexity, the need to use sophisticated equipment, the use of the mechanical principle of setting the exposure time, which reduces the accuracy of determining the inertia time.

A device for studying the throughput of a human visual analyzer based on a small PROMIN-M digital computer, including a digital display, its control units, delay device (PP9-2m), analysis units for receiving the accuracy of a digital signal and a memory unit [2]. As test signals use the numbers shown on digital lamps IN-1 on the electronic computer every 7 seconds. The display shows the first number from the digital array with the exposure time set before the experiment, after which an erasing image appears on the display. The test subject recognizes each number and types it on the keyboard. The dispatcher program compares this number with the subject typed on the keyboard. The error and exposure time at which it was made is recorded.

Recognition time, that is, the time required for image recognition, depends on the inertia parameters of the visual system and is determined by the time of perception of visual information [3, 4].

The disadvantage of this device is its complexity and the long duration of the experiment, which leads to fatigue of the visual system and a decrease in the accuracy of measurements.

The closest in technical essence to the present invention is a device for studying the inertia parameters of the human visual system, containing a second pulse generator, a millisecond pulse generator, a first one-shot, a second one-shot with an adjustable pulse duration, a third one-shot, an AND element, an OR element, a counter, a control panel , a light source and an indication unit, wherein the output of the AND element is connected to the first input of the counter, the output of which is connected to the first input of the indication unit , the first output of the control panel is connected to the first input of the light source, the output of the first one-shot is connected to the second input of the counter, the second input of the display unit is connected to the second output of the control panel, the output of the millisecond pulse generator is connected to the first input of the element And, the output of the second pulse generator is connected to the input the first one-shot, the output of which is connected to the first input of the OR element and to the first input of the second one-shot with an adjustable pulse duration, the output of which is connected to the second input ohm of the AND element and with the input of the third one-shot, the output of which is connected to the second input of the OR element, the output of which is connected with the second input of the light source, the third output of the control panel is connected to the second input of the second one-shot with an adjustable pulse duration [5].

The disadvantage of this device is the inability to investigate the time of inertia of the human visual system while presenting light pulses.

The time of inertia of the human visual system with the simultaneous presentation of two light pulses is equal to the value of the early end time of the pulse that is adjustable in duration relative to the end time of the reference constant in duration at the moment of subjective sensation that the light pulses do not end simultaneously [6].

The inventive device allows to study the time of inertia of the visual system while simultaneously presenting two light pulses in a shorter period of time, which reduces the fatigue of the visual system. It does not require the use of sophisticated equipment.

In the present invention, in a device for studying the inertia parameters of the human visual system, containing a second pulse generator, a millisecond pulse generator, a first one-shot, a second one-shot with adjustable pulse duration, a third one-shot, element And, counter, control panel, light source and display unit, output element And is connected to the first input of the counter, the output of which is connected to the first input of the display unit, the second input of which is connected to the second output of the control panel, you the course of the millisecond pulse generator is connected to the first input of the And element, the first output of the control panel is connected to the second input of the second one-shot with an adjustable pulse duration, an exclusive OR element and a second light source are introduced, the output of the second pulse generator being connected to the input of the third one-shot, the second output of which connected to the second input of the counter, and the first output to the input of the first one-shot and the first input of the second one-shot, the first output of which is connected to the input ohm of the second light source, and the second output - exclusive OR, with the second input of the element, the first input of which is connected to the output of the first one-shot, and the output - with the second input of the And element, the first input of which is connected to the output of the millisecond pulse generator.

The inventive device due to the introduction of an exclusive OR element and a second light source allows:

- to study the inertia of the visual system with the simultaneous presentation of two light pulses;

- reduce the duration of the experiment due to the simultaneous presentation of light stimuli;

- reduce the fatigue of the visual system by reducing the duration of the experiment;

- conduct research without the use of sophisticated equipment.

Thus, the claimed device differs from the known new properties that determine the receipt of a positive effect.

Figure 1 presents a structural diagram of the inventive device, figure 2 is a timing diagram of the operation of the inventive device.

3 shows a sequence of pairs requirements light pulses through repetitive time interval T equal to 1, where Figure 3a - a timing sequence diagram of reference light pulses, the duration of each _pulses τ = 80 ms; figb is a timing chart of a sequence of adjustable duration pulses, each of which ends earlier than the reference at a time t _OK , while the subject has a feeling that the pulses end simultaneously; figv is a timing diagram of a sequence of adjustable duration pulses, each of which ends earlier than the reference for a threshold time t _ok.pore , causing a feeling that the presented pulses do not end simultaneously.

The inventive device contains a generator of 1 second pulses, a generator of 2 millisecond pulses, the first 3 one-shot, the second 4 one-shot with adjustable pulse duration, the third 5 one-shot, element 6 AND, element 7 exclusive OR, counter 8, remote control 9, the first light source 10, a second light source 11 and an indication unit 12.

The generator of 1 second pulses is designed to generate a sequence of pulses with a frequency of 1 Hz, providing a given repetition time of paired test pulses, and can be performed according to the known scheme.

The generator of 2 millisecond pulses is designed to generate counting pulses with a frequency of 1 kHz, providing a measurement accuracy of 1 ms, and can be performed according to the known scheme.

The first 3 one-shot is designed to generate a pulse of a given duration equal to 80 ms. The third 5 one-shot is designed to generate a short pulse, resetting the counter 8 and starting the second 4 one-shot. The second 4 one-shot vibrator with adjustable pulse width is designed to change the end time of presentation of a variable-duration pulse relative to the reference pulse within 5-150 ms. Single vibrators 3, 4, 5 can be performed, for example, using the K155AG1 microcircuit, which can be launched both on the leading and trailing edges of the incoming pulses, according to the scheme [7, Fig. 4.20, p.216].

Counter 8 is designed to determine the adjustable delay of presentation of one pulse relative to another with an accuracy of 1 ms.

Sources of light 10 and 11 are intended for the presentation of light pulses and are made, for example, on the LEDs ALS307EM.

The indicators on the display unit 12 are designed to display the magnitude of the adjustable delay in the presentation of one pulse relative to another and can be performed, for example, on indicators of the type ALS333A.

The remaining functional units of the structural diagram are well known.

The device operates as follows. When the power is turned on, counter 8 is reset (circuits not shown). The pulse generator 1 generates pulses with a frequency of 1 Hz (figa), received at the input of a one-shot 5, which generates a short pulse on the leading edge of each pulse (fig.2b), triggering a one-shot 3 and resetting the counter 8. One-shot 3 generates a pulse of a given duration (figv), arriving at the input of the first light source 10, and starts a one-shot 4, generating a pulse, the duration of which is set by the subjects from the control panel 9 within the specified limits (fig.2d).

The pulses from the output of the one-shot 4 are fed to the input of the second light source 11. As a result, the test subject is presented with two pulses, one of which arriving at the second light source 11 ends before the reference arriving at the first light source 10.

Simultaneously, from the output of the one-shot 4 pulses are fed to the second input of the element 7 exclusive OR, to the first input of which pulses are received from the output of the one-shot 3. From the output of the item 7, the exclusive OR pulse, the duration of which is equal to the time of the early end of the presentation of a pulse regulated by duration relative to the reference (Fig. 2e), enters the second input of element 6 AND, the first input of which receives pulses from the output of generator 2 (Fig.2e). From the output of element 6 And a packet of pulses arrives at the first input of counter 8 (Fig. 2g), the counting result is displayed in the display unit 12. The number of pulses in the packet is equal to the pulse duration at the output of element 7 exclusive OR, that is, the time of the early end of the pulse arriving at the second 11 light source, relative to the time of the end of the pulse arriving at the first 10 light source, in ms.

When the delay in the presentation of the adjustable pulse duration relative to the reference for a time t _ok <t _{ok pore} (Fig.3b), the subject has a feeling that the pulses end simultaneously. The test of the rotation of the handle of the potentiometer of the control panel 9 reduces the duration of the pulses at the output of the one-shot 4, increasing the time for the early end of the presentation of a pulse that is adjustable in duration relative to the reference one until the subjective sensation that the light pulses do not end simultaneously (Fig. The threshold time for the early end t of the _{target pore of the} pulse arriving at the second 11 light source, relative to the end time of the pulse arriving at the first 10 light source, is fixed at this moment and taken equal to the inertia time of the visual system.

To read the value of the inertia time, the test person via the control panel 9 supplies power to the display unit 12, the indicators of which display the value of the inertia time of the visual system in ms.

To study the inertia of the visual system, the test subject is presented with a sequence of pairs of pulses of duration t _imp (Fig. 3a), repeating over time interval T. During responses to light stimuli, the receptive field of a small neuron appears first. Then the receptive field expands, after which it weakens, fragmentes and disappears. After the disappearance of the receptive field, the neural structures return to their original state and become ready for the perception of a new stimulus. Since the appearance of the receptive field occurs 20–80 ms after the inclusion of the light stimulus [8], the duration of the reference pulse is taken to be 80 ms.

The time interval T is selected from the condition of eliminating the influence of the masking effect. Masking consists in the deterioration of the perception of the first time light pulse due to the presentation of the second pulse in the immediate spatio-temporal proximity to the first. It is shown that there is not only a reverse effect, but also direct masking, in which the first light pulse affects the quality of perception of the second [9]. At an interpulse interval of 500 ms, masking effects are absent or weakly expressed [10]. To eliminate the masking effect, a sequence of pairs of light pulses is presented at a constant time interval of 1 s.

Thus, the proposed device allows you to explore the time of inertia of the visual system while simultaneously presenting two light stimuli for a shorter period of time, which reduces the fatigue of the visual system. It does not require the use of sophisticated equipment.

Information sources

1. Luizov A.V. Eye and light. - L .: Energy, 1983. - 140 p.

2. Meshcheryakov V.A., Shabaev V.V., Casanovskaya I.A. Technique of automatic tachistoscopy with feedback // Human Physiology. - 1977. - T.3. - No. 3. - S.549-552.

3. Ivanitsky A.M. Brain potentials in mental operations of varying degrees of complexity // Human Physiology. - 1989.- T.15. - No. 3. - S.11-18.

4. Sagittarius VB Violation of the physiological mechanisms of perception, emotions and thinking in certain types of mental pathology // Human Physiology. - 1989.- T.15. - No. 3. - S.135-144.

5. Patent 2220656 of the Russian Federation, IPC ⁷ A61B 5/16. A device for studying the parameters of inertia of the human visual system / V.V. Rozhentsov, I.V. Petukhov // BI - 2004. - No. 1.

6. Patent 2262293 of the Russian Federation, IPC ⁷ A61B 3/02. A method for determining the time of inertia of the human visual system. / Petukhov I.V., Lezhnin A.V., Rozhentsov V.V. - Publ. 10/20/2005, Bull. Number 29.

7. Calculation of elements of digital devices: Textbook. allowance / L.N. Presnukhin, N.V. Vorobiev, A.A. Shishkevich; Ed. L.N. Presnukhina. - 2nd ed., Revised. and add. - M.: Higher School, 1991 .-- 526 p.

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

9. 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. - P.561.

10. 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 - C.5-14.

Claims (1)

A device for studying the time of inertia of the human visual system, containing a second pulse generator, a millisecond pulse generator, a first one-shot, a second one-shot with an adjustable pulse duration, a third one-shot, an element And, a counter, a control panel, a light source and an indication unit, the output of the element And is connected to the first input of the counter, the output of which is connected to the first input of the display unit, the second input of which is connected to the second output of the control panel, the output of the millisecond generator and pulse is connected to the first input of the And element, the first output of the control panel is connected to the second input of the second one-shot with an adjustable pulse duration, characterized in that it contains an exclusive OR element and a second light source, and the output of the second pulse generator is connected to the input of the third one-shot, the second output which is connected to the second input of the counter, and the first output to the input of the first one-shot and the first input of the second one-shot, the output of which is connected to the input of the second light source and the second input of the exclusive OR element, the output of which is connected to the second input of the AND element, the output of the first one-shot is connected to the input of the first light source and to the first input of the exclusive OR element.

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