RU2240029C1 - Device for determining receptive vision system neuron fields bandwidth - Google Patents

Abstract

FIELD: medical engineering.

SUBSTANCE: device has the first-sixth keys, tumbler, the first-third demultiplexor units, trigger, the first and the second mode switches, the first and the second linearly variable voltage oscillators, analog-type multiplexor, second-long pulse oscillator, voltage-to-frequency converter, luminous pulses source, calculator unit, the first and the second indicator units, the first and the second rectifier, the first and the second monovibrators, OR-gate and counter.

EFFECT: simplified bandwidth measurement.

2 dwg

Description

The invention relates to medical equipment and is intended to determine the passband of the receptive fields of the neurons of the visual system.

A device is known for processing impulse activity of neurons and constructing spatial-frequency characteristics of receptive fields of the visual system, containing a linear filter, a nonlinear filter, a block for allocating informative sections in the impulse activity of neurons, an OR circuit, an address code generation unit, an And circuit, memory and arithmetic analyzer devices, stimulus movement control device [1, Fig. 77, p.140]. If there are signals at all three inputs of the AND circuit, the pulses of the process under study are sent to the arithmetic device of the analyzer, summed and transmitted to the storage device at the address corresponding to the spatial frequency and position of the area allocated by the block for the selection of informative areas in the impulse activity of neurons. The analyzer memory is divided into groups, the number of which corresponds to the number of sections allocated in the impulse activity of neurons, the number of memory cells in each group is equal to the number of stimuli, and an estimate of the response of a neuron to a specific spatial frequency is recorded in each cell. The procedure for presenting the entire set of stimuli, which are lattices with different spatial frequencies, is repeated several times [1, p.141].

It is known to determine the bandwidth of receptive fields of neurons of the visual system using arrays of different spatial frequencies with a sinusoidal distribution of illumination [2]. For the formation of images of various shapes — the world of variable contrast, different spatial frequencies with a sinusoidal brightness profile, two-dimensional gratings with a sinusoidal brightness distribution, a programmable synthesizer is known that contains a microcomputer, an interface, a control synchronization unit, a test answer input panel, video buffer, a digital-to-analog converter, video monitoring device, operator terminal and plotter [3, Fig. 38, p. 68]. The images being formed are displayed on the screen of the video monitoring device, the test subject’s response is entered into the computer by pressing the “see” - “do not see” buttons [3, p. 84].

The disadvantages of the known devices are the long preparatory period, the need for sophisticated special equipment, the complexity of research.

The closest in technical essence to the present invention is a device for studying the critical flicker fusion frequency, containing a test button, first, second and third triggers, first and second waiting multivibrators, a mode switch, a ramp generator, a voltage-frequency converter, a light pulse source , a comparator, a failure indicator, a shift register, an OR element, a calculator and a block of indicators, and the output of the generator is connected to the inputs of the comparator and a voltage-frequency generator, the outputs of which are connected respectively to the inputs of the failure indicator and the source of light pulses, the outputs of the first, second, and third triggers are connected through a mode switch to the generator input, the output of the first standby multivibrator is connected to the first input of the second trigger and the input of the second standby multivibrator, output which is connected to the second inputs of the second and third triggers, the test button output is connected to the input of the shift register, the first output of which is connected to the first input m of the first trigger, the second output - with the second input of the second trigger and the input of the first waiting multivibrator, the third output - with the first input of the OR element and the third trigger, the second input of the OR element is connected to the output of the first waiting multivibrator, and the output - with the first input of the calculator, the second the input of which is connected to the output of the voltage-frequency converter, and the output is connected to the input of the indicator block [4].

The disadvantage of this device is the inability to determine the passband of the receptive fields of the neurons of the visual system.

In the present invention, in a device for studying a critical flicker fusion frequency, comprising a mode switch, a ramp generator, a voltage-frequency converter, a light pulse source, an OR element, a calculator and a block of indicators, the output of the mode switch being connected to the generator input, the output of the OR element connected to the first input of the calculator, the second input of which is connected to the output of the voltage-frequency converter, and the output to the input of the indicator block, the output of the converter If the voltage-frequency is also connected to the input of the light pulse source, a second mode switch, a second ramp generator, a second block of indicators, a second pulse generator, an analog multiplexer, a counter, the first and third demultiplexers, a trigger, the first and second valves, the first are additionally introduced a third one-shot, first to sixth keys and a toggle switch, and the outputs of the first and second keys are connected to the inputs of the first and second mode switches, the outputs of the third to fifth keys are connected respectively, with the information inputs of the first and third demultiplexers, the first outputs of which are connected to the inputs of the first mode switch, the second outputs are connected to the inputs of the second mode switch, the output of the sixth key is connected to C - the trigger input, the output of which is connected to the first input of the first valve, R-input connected to the second output of the calculator, and the D-input - with the normally open output of the toggle switch, the normally closed output of which is connected to the first input of the second valve, the output of the second mode switch is connected to the input ohm of the second ramp generator, the outputs of the first and second ramp generators are connected to the information inputs of the analog multiplexer, the output of which is connected to the voltage-frequency converter input, the output of the second pulse generator is connected to the address input of the analog multiplexer, the second inputs of the first and second valves and address inputs of the first to third demultiplexers, the output of the first gate is connected to the inputs of the first and second single vibrators, the outputs to toryh connected to inputs of an element or inverse output of the second gate is connected to the input of the third monostable multivibrator and the input of the permission counter counting, the counting input of which is connected to the output voltage of the inverter-frequency input nulling - a yield of a third monostable multivibrator, while the output - to the input of the second display unit.

The inventive device due to the introduction of a second mode switch, a second ramp generator, a second block of indicators, a second pulse generator, an analog multiplexer, a counter, the first to third demultiplexers, a trigger, the first and second valves, the first and third single vibrators, the first to sixth keys and the toggle switch allows you to determine the passband of the receptive fields of the neurons of the visual system, while

- reduce the preparatory period,

- simplify the determination procedure,

- use less sophisticated special 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 temporary diagram explaining its operation.

The inventive device contains the first sixth 1-6 keys, toggle switch 7, the first - third 8-10 demultiplexers, trigger 11, the first 12 and second 13 mode switches, the first 14 and second 15 linearly varying voltage generators, 16 analog multiplexer, 17 second generator pulses, a voltage-frequency converter 18, a light pulse source 19, a calculator 20, a first 21 block of indicators, a first 22 and a second 23 valves, a first and a third 24-26 one-shot, element 27 OR, a counter 28, a second 29 block of indicators.

The switches 12-13 modes are designed for switching resistors at the inputs of the generators 14-15.

The calculator 20 is designed to determine the difference between the incremental and decrement frequencies of light flickers equal to the passband of the receptive fields of the neurons of the visual system.

The first 21 block of indicators is designed to indicate the bandwidth of the receptive fields of the neurons of the visual system.

The second 29 block of indicators is designed to indicate the initial frequency of light flicker.

The first 1 switch is used to set the first 14 and second 15 generators in the mode of linearly increasing voltage generation at a speed corresponding to a change in the frequency at the output of the voltage-to-frequency converter 18 equal to 1 Hz / s.

The second 2 key is designed to set the first 14 and second 15 generators in the mode of generating a linearly incident voltage at a speed corresponding to a change in frequency at the output of the voltage-frequency converter 18 equal to 1 Hz / s.

The third 3 key is designed to set the first 14 generators in the ramp voltage generation mode and the second 15 generators in the ramp voltage generation mode with a speed corresponding to the frequency change at the voltage-frequency converter output 18 equal to 2 Hz / s.

The fourth 4 key is designed to set the first 14 generator in the mode of linearly incident voltage generation and the second 15 generator in the mode of linearly increasing voltage generation at a speed corresponding to a change in frequency at the output of the voltage-to-frequency converter 18 equal to 0.5 Hz / s.

The fifth 5 key is used to set the first 14 generator in the mode of linearly increasing voltage generation and the second 15 generator in the mode of linearly decreasing voltage generation at a speed corresponding to the frequency change at the output of the voltage-to-frequency converter 18 equal to 0.5 Hz / s.

The sixth 6 key is intended for fixing the measurement results.

The toggle switch 7 is designed to set the initial frequency setting modes and determine the bandwidth of the receptive fields of neurons.

The purpose of the remaining nodes corresponds to their name.

Demultiplexers 8-10 and analog 16 multiplexer are made on K 561 KP 1 microcircuits [5, Fig. 3.38, p. 314].

The trigger 11 is made on the chip K 561 TM 2 [5, Fig. 3.50, p.323].

The mode switches 12-13 are made according to the patent of 2026008 RF, A 61 V 5/16 (node 8).

The linearly varying voltage generator 15 is made similarly to the generator 14. As the linearly varying voltage generators 14-15, a standard integrator is used on an operational amplifier with input resistors switched by switches 12-13, respectively, to obtain a different voltage rise rate at the output of the generators 14-15, and by changing the polarity of the input voltage, change the direction of integration (rise or fall of the output voltage).

The counter 28 is made on the K 561 IE 8 microcircuits [5, Fig. 3.62, p. 333].

Keys 1-6 are manual switches to two positions for closing and opening electrical control circuits and are made in the form of control buttons.

The remaining nodes are well known.

The device operates as follows. In the initial state, the toggle switch 7 is in a position corresponding to the initial frequency setting mode, as shown in FIG. When the power is turned on, the trigger 11 is turned off, the counter 28 is reset (chains are not shown), the second valve 23 opens, the generators 14-15 produce the same constant voltage corresponding to a light flicker frequency of 25 Hz, that is, the average frequency of the accepted visible range of light flickers from 0 up to 50 Hz. The same constant voltage from the outputs of the generators 14-15, regardless of the state of the output of the generator 17 second pulses through the multiplexer 16 is supplied to the Converter 18, where it is converted to the frequency that controls the source 19.

The test subject closes the first 1 or second 2 keys sets a given initial F _H frequency, relative to which it is necessary to determine the passband of the receptive fields of the neurons of the visual system. When the first 1 key is closed, the generators 14-15 through the corresponding switches 12-13 are installed in the mode of linearly increasing voltage generation at a given speed, when the second 2 keys are closed, in the mode of linearly decreasing voltage generation at the same speed.

The signal of a logical unit with a duration of 1 from the generator 17 goes to the open second 23 valve, is inverted and goes to the third 26 single-vibrator and the counter enable input 28. At the beginning of the logic zero signal from the inverse output of the second 23 valve, the third 26 single-vibrator generates a short pulse that resets the counter 28. The frequency from the output of the Converter 18 is supplied to the counting input of the counter 28, the counting result is displayed on the second 29 block of indicators. The set predetermined initial F _H frequency controls the source 19 (FIG. 2, time interval 0-T ₀ ).

The test subject sets the toggle switch 7 to the position corresponding to the mode for determining the bandwidth of the receptive fields of neurons, a logical unit signal is sent to the D-input of trigger 11, the second 23 valve closes, the state of the counter 28 does not change, the value of the set initial F _H frequency is displayed on the second 29 indicator block .

The subject closes the third 3 key (figure 2, the time T _about ). When the logic unit signal at the output of the generator 17, the signal from the output of the third 3 keys through the first 8 demultiplexer and the first 12 switch sets the first 14 generator in the mode of generating a ramp voltage with a given speed. The voltage from the output of the first 14 generator through the multiplexer 16 is supplied to the converter 18, where it is converted to the frequency that controls the source 19. When the signal is a logic zero at the output of the generator 17, the signal from the output of the third 3 keys through the first 8 demultiplexer and the second 13 switch sets the second 15 generator into the mode of linearly incident voltage generation at the same speed. The voltage from the output of the second generator 15 through the multiplexer 16 is supplied to the converter 18, where it is converted to a frequency that controls the source 19 (figure 2, the time interval T ₀ -T ₁ ).

On the time interval T ₀ -T _{1 the} subject determines the moment when presented alternately incremental F _and decrement F _d light flicker frequencies are different, and opens the third 3 key (figure 2, time T ₁ ). The generators 14-15 store at the outputs a constant voltage corresponding to the frequencies F _I1 and F _{D1 of} light flickers, which source 19 is presented to the subject in turn (figure 2, the time interval T ₁ -T ₂ ).

The subject closes the fourth 4 key (figure 2, time T ₂ ). When the logic unit signal at the output of the generator 17, the signal from the output of the fourth 4 keys through the second 9 demultiplexer and the first 12 switch sets the first 14 generator in the mode of generating a linearly incident voltage with a given speed. The voltage from the output of the first 14 generator through the multiplexer 16 is supplied to the converter 18, where it is converted to a frequency that controls the source 19. When the signal is a logic zero at the output of the generator 17, the signal from the output of the fourth 4 keys through the second 9 demultiplexer and the second 13 switch sets the second 15 generator in the mode of generation of a ramp with the same speed. The voltage from the output of the second 15 generator through the multiplexer 16 is supplied to the converter 18, where it is converted to a frequency that controls the source 19 (figure 2, the time interval T ₂ -T ₃ ).

On the time interval T ₂ -T _{3 the} test subject determines the moment when the alternate F _and decrement F _d light flicker frequencies presented alternately do not differ, and the fourth 4 key opens (Fig. 2, time point T ₃ ). The generators 14-15 store at the outputs a constant voltage corresponding to the frequencies F _I2 and F _{D2 of} light flickers, which source 19 is presented to the subject in turn (figure 2, the time interval T ₃ -T ₄ ).

The test person closes the fifth 5 key (figure 2, time T ₄ ). When the logical unit signal at the output of the generator 17, the signal from the output of the fifth 5 key through the third 10 demultiplexer and the first 12 switch sets the first 14 generator in the mode of generating a ramp voltage with a given speed. The voltage from the output of the first 14 generator through the multiplexer 16 is supplied to the converter 18, where it is converted to the frequency that controls the source 19. When the signal is a logic zero at the output of the generator 17, the signal from the output of the fifth 5 key through the third 10 demultiplexer and the second 13 switch sets the second 15 generator into the mode of linearly incident voltage generation at the same speed. The voltage from the output of the second 15 generator through the multiplexer 16 is supplied to the Converter 18, where it is converted to a frequency that controls the source 19 (figure 2, the time interval T ₄ -T ₅ ).

On the time interval T ₄ -T _{5, the} test subject determines the moment when the incremental F _and decrement F _d light flicker frequencies are presented alternately, and the fifth key 5 opens (Fig. 3, time point T ₅ ). The generators 14-15 store at the outputs a constant voltage corresponding to the frequencies F _I3 and F _{D3 of} light flickers, which source 19 is presented to the subject in turn (Fig. 3, time interval T ₅ -T ₆ ).

The test subject closes the sixth key 6 for a short time (Fig. 2, time point T ₆ ), the pulse from the output of the sixth key 6 arrives at the C-input of trigger 11 and turns it on, the first 22 valve opens.

The signal from the output of the generator 17 through the open first 22 valve enters the first 24 and second 25 single vibrators. The first 24 one-shot at the leading edge of the signal of the logical unit generates a pulse, which through the element 27 OR is supplied to the calculator 20, which records the value of the last incremental F _{from the} frequency of light flicker. The second 25 one-shot at the trailing edge of the signal of the logical unit generates a pulse, which through the OR element 27 is supplied to the calculator 20, in which the value of the last decrement F _F3 light flicker frequency is recorded.

The calculator 20 determines the difference between the incremental and decrement frequencies ΔF = F _И3 -F _Д3 , equal to the passband of the receptive fields of the neurons of the visual system relative to the initial frequency F _H , and displays the result on the first 21 block of indicators, after which it generates a pulse that turns off trigger 11, and also resetting the device (circuits not shown).

Thus, the proposed device allows you to determine the passband of the receptive fields of neurons of the visual system.

Literature

1. Dudkin K.N., Gauselman V.E. Automation of a neurophysiological experiment. - L .: Nauka, 1979. - 160 p.

2. Kulikowski J.J., Vidyasagar T.R. Space and spatial frequency: analysis and representation in the macaque striate cortex // Exp. Brain Res. - 1986. - V. 64. - No. 1. - R.6-18.

3. Shelepin Yu.E., Kolesnikova LN, Levkovich Yu.I. Visocontrastometry: Measurement of the spatial transfer functions of the visual system. L .: Nauka, 1985 .-- 103 p.

4. Patent 2026008 of the Russian Federation, MKI A 61 V 5/16. A device for studying the critical frequency of flicker fusion / V.V. Rozhentsov (RF). - Publ. 01/10/95, Bull. No. 1. - 4 p.

5. Digital integrated circuits: Reference book / M.I. Bogdanovich, I. N. Grel, S. A. Dubina and others. - 2nd ed., Revised. and add. - Minsk: Belarus, Polymya, 1996 .-- 605 p.

Claims (1)

A device for determining the bandwidth of the receptive fields of the neurons of the visual system, comprising a mode switch, a ramp generator, a voltage-frequency converter, a light pulse source, an OR element, a computer and an indicator block, the output of the mode switch being connected to the generator input, the output of the OR element being connected with the first input of the calculator, the second input of which is connected to the output of the voltage-frequency converter, and the output is with the input of the indicator block, the output of the converter I voltage-frequency is also connected to the input of the light pulse source, characterized in that it additionally introduces a second mode switch, a second ramp generator, a second indicator block, a second pulse generator, an analog multiplexer, a counter, the first and third demultiplexers, a trigger, the first and second valves, the first to third single vibrators, the first to sixth keys and a toggle switch, and the outputs of the first and second keys are connected to the inputs of the first and second mode switches, the outputs of the third the fifth key is connected respectively to the information inputs of the first to third demultiplexers, the first outputs of which are connected to the inputs of the first mode switch, the second outputs are connected to the inputs of the second mode switch, the output of the sixth key is connected to the C-input of the trigger, the output of which is connected to the first input of the first valve , The R-input is connected to the second output of the calculator, and the D-input is with the normally open output of the toggle switch, the normally closed output of which is connected to the first input of the second valve, the output of the second switch modes connected to the input of the second ramp generator, the outputs of the first and second ramp generators are connected to the information inputs of the analog multiplexer, the output of which is connected to the voltage-frequency converter input, the output of the second pulse generator is connected to the address input of the analog multiplexer, the second inputs of the first and second gates and address inputs of the first to third demultiplexers, the output of the first gate is connected to the inputs of the first and second of the one-shot vibrators, the outputs of which are connected to the inputs of the OR element, the inverse output of the second valve is connected to the input of the third one-shot and the counter resolution input of the counter, the counting input of which is connected to the voltage-frequency converter output, the zeroing input to the output of the third one-shot, and the output to the input of the second block of indicators.

Images