RU2451481C1 - Measurement unit for pass band of receptive fields of visual neurons - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: invention refers to medical equipment and aims at measuring a pass band of receptive fields of visual neurons. A unit comprises first-fourth keys, a toggle switch, first-third multiplexers, first-second mode switches, first-second ramp voltage generators, first-second voltage-to-frequency converters, first-second light pulse source units, a calculator, a second pulse generator, a counter, first-second display units, first-fourth single vibrators, a trigger, first-second gates and an OR element.

EFFECT: measurement unit enables higher accuracy of measuring the pass band of receptive fields of visual neurons that is ensured by simultaneous presentation of incremental and decrement flicker frequencies that provides avoiding long-time logical-semantic memory.

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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 buttons “see” and “do not see” [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 containing a mode switch, a ramp generator, a voltage-frequency converter, a light pulse source, an OR element, a computer and a block of indicators, the output of the mode switch connected to the input of the generator, the output of the OR element 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 voltage-frequency is also connected to the input of the light pulse source, characterized in that it additionally includes 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 gates, first-third one-shots, first-sixth keys and a toggle switch, the outputs of the first and second keys being connected to the inputs of the first and second mode switches, the outputs of the third-fifth of the keys are 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 gate, 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 presses 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 an 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 one 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 [4].

The disadvantage of this device is the low accuracy of determining the bandwidth of receptive fields of neurons of the visual system, due to the need to use memory functions, in particular, access to long-term logical-semantic memory.

The technical result of the proposed device for determining the passband of the receptive fields of the neurons of the visual system is to increase the accuracy of the measurement.

The technical result is achieved by the fact that the device contains first-second mode switches, first-second ramp generators, voltage-frequency converter, light pulse source, OR element, calculator, first-second indicator blocks, second pulse generator, counter, trigger, first-second gates, first-third one-shots, first-fourth keys and a toggle switch, the outputs of the first and second mode switches are connected respectively to the inputs of the first and second generators, the output is ele OR is connected to the second input of the calculator, the first output of which is connected to the input of the first block of indicators, the second output is to the R-input of the trigger, the input of the voltage-frequency converter is connected to the output of the first generator, and the output is connected to the input of the light pulse source and the counting input of the counter , the outputs of the first and second keys are connected respectively to the first or second inputs of the first mode switch, the normally closed output of the toggle switch is connected to the first input of the second valve, the output of the second pulse generator is connected to the second inputs of the first and second gates, the first input of the first gate is connected to the output of the trigger, and the output is connected to the inputs of the first and second one-shots, 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 enable input, input the zeroing of which is connected to the output of the third one-shot, and the output to the input of the second block of indicators, and the new one is that the first and third multiplexers, the second voltage converter frequency, a second source of light pulses and a fourth one-shot, and the output of the first key is also connected to the first input of the first multiplexer and the second input of the second multiplexer, the outputs of which are connected respectively to the first and third inputs of the second mode switch, the output of the second key is also connected to the second input of the first multiplexer and the first input of the second multiplexer, the output of the third key is connected to the third input of the first mode switch and the second input of the second mode switch, the output is four The grounded key is connected to the fourth inputs of the first and second mode switches and the input of the fourth one-shot, the output of which is connected to the S-input of the trigger, the normally open output of the toggle switch is connected to the address inputs of the first and second multiplexers, the output of the second generator is connected to the input of the second voltage-frequency converter, the output of which is connected to the input of the second source of light pulses and the second input of the third multiplexer, the first input of the third multiplexer is connected to the output of the first converter For voltage-frequency, the address input is with the output of the second pulse generator, and the output is with the first input of the calculator.

The inventive device due to the introduction of the first or third multiplexers, the second voltage-frequency converter, the second light pulse source and the fourth one-shot improves the accuracy of determining the passband of the receptive fields of the neurons of the visual system due to the elimination of the need for access to long-term logical-semantic memory in the measurement process.

Thus, the claimed device differs from the known new property, which determines the receipt of a positive effect.

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

The inventive device contains a first-fourth 1-4 keys, toggle switch 5, first-third 6-8 multiplexers, first-second 9-10 mode switches, first-second 11-12 linear voltage generators, first-second 13-14 voltage converters -frequency, first-second 15-16 sources of light pulses, calculator 17, generator 18 second pulses, counter 19, first-second 20-21 indicator blocks, first-fourth 22-25 single vibrators, trigger 26, first-second 27-28 valves and element OR 29.

The first switch 1 is used to set the first 11 and second 12 generators in the mode of generating a ramp voltage at a speed corresponding to a change in frequency at the output of the voltage-frequency converters 13-14, equal to 1 Hz / s.

The second switch 2 is designed to set the first 11 and second 12 generators in the mode of generating a linearly incident voltage at a speed corresponding to a change in the frequency at the output of the voltage-frequency converters 13-14, equal to 1 Hz / s.

The third switch 3 is used to set the first generator 11 in the mode of linearly incident voltage generation and the second generator 12 in the mode of linearly increasing voltage generation at a speed corresponding to a change in frequency at the output of voltage-frequency converters 13-14 equal to 0.25 Hz / s.

The fourth switch 4 is used to set the first generator 11 to the ramp voltage generation mode and the second generator 12 to the ramp voltage generation mode at a speed corresponding to a change in the frequency at the output of the voltage-frequency converters 13-14, equal to 0.25 Hz / s.

Keys 1-4 are manual switches to two positions for closing and opening electrical control circuits and are made in the form of control buttons.

The remaining functional nodes of the structural diagram are well known or correspond to similar functional nodes of the structural diagram of the prototype.

The device operates as follows. In the initial state, the toggle switch 5 is in the position corresponding to the setting mode of the initial frequency, as shown in figure 1. When the power is turned on, the trigger 26 turns off, the counter 19 is reset (the circuit is not shown), the second valve 28 opens, the generators 11-12 produce the same constant voltage corresponding to a light flicker frequency of 25 Hz, i.e. 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 11-12 are supplied to the converters 13-14, where they are converted to a frequency that controls the sources 15-16.

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 key 1 is closed, the generator 11 through the switch 9 is installed in the mode of generating a ramp voltage with a given speed. At the same time, the signal from the output of the first switch 1 through the multiplexer 6 and the switch 10 sets the generator 12 in the mode of generating a ramp voltage at the same speed. When the second key 2 is closed, the generator 11 through the switch 9 is set to the mode of generating a linearly incident voltage at a given speed. At the same time, the signal from the output of the second switch 2 through the multiplexer 7 and the switch 10 sets the generator 12 in the mode of generating a linearly incident voltage at the same speed.

The signal of a logical unit with a duration of 1 s from the generator 18 is fed to the open second valve 28, inverted and fed to the third one-shot 24 and the counter resolution input of the counter 19. At the beginning of the signal of the logic zero from the inverted output of the second valve 28, the third one-shot 24 produces a short pulse, which resets counter 19. The frequency from the output of the Converter 13 is supplied to the counting input of the counter 19, the counting result is displayed on the second block 21 of the indicators. The set predetermined initial F _H frequency controls the sources 15-16 (figure 2, the time interval 0-T ₀ ).

The test subject sets the toggle switch 5 to the position corresponding to the mode for determining the passband of the receptive fields of neurons, the second valve 28 closes, the state of the counter 19 does not change, the value of the set initial F _H frequency is displayed on the second block 21 of the indicators. The signal from the output of the toggle switch through a normally open contact is fed to the address inputs of multiplexers 6-7.

The test person closes the first key 1 (figure 2, the time T ₀ ), the generator 11 through the switch 9 is set to generate a linearly increasing voltage at a given speed. At the same time, the signal from the output of the first switch 1 through the multiplexer 7 and the switch 10 sets the generator 12 in the mode of generating a linearly incident voltage at the same speed. The voltages from the outputs of the generators 11-12 are supplied to the converters 13-14, where they are converted to a frequency that controls the sources 15-16 (figure 2, the time interval T ₀ -T ₁ ).

On the time interval T ₀ -T _{1 the} subject determines the moment when presented simultaneously with incremental F _And decrement F _D light flicker frequencies are different, and opens the first key 1 (figure 2, time T ₁ ). The generators 11-12 store at the outputs a constant voltage corresponding to the frequencies F _I1 and F _{D1 of} light flickers, which are presented to the test person by sources 15-16 (figure 2, the time interval T ₁ -T ₂ ).

The test subject closes the third key 3 (Fig. 2, time moment T ₂ ), the generator 11 through the switch 9 is set to the mode of linearly decreasing voltage generation at a given speed, the generator 12 through the switch 10 - to the mode of generating linearly increasing voltage at the same speed. The voltages from the outputs of the generators 11-12 are supplied to the converters 13-14, where they are converted to the frequency that controls the sources 15-16 (figure 2, the time interval T ₂ -T ₃ ).

On the time interval T ₂ -T _{3 the} subject determines the moment when presented simultaneously with incremental F _And decrement F _D light flicker frequencies do not differ, and opens the third key 3 (figure 2, time T ₃ ). The generators 11-12 store at the outputs a constant voltage corresponding to the frequencies F _I2 and F _{D2 of} light flickers, which are presented to the test person by sources 15-16 (figure 2, the time interval T ₃ -T ₄ ).

The test subject closes the fourth key 4 (figure 2, time T ₄ ), the generator 11 through the switch 9 is set to the mode of linearly increasing voltage generation at a given speed, the generator 12 through the switch 10 - to the mode of generating linearly incident voltage at the same speed. The voltages from the outputs of the generators 11-12 are supplied to the converters 13-14, where they are converted to a frequency that controls the sources 15-16 (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 _I and the decrement F _D light flickering frequencies are presented at the same time, and the fourth key 4 opens (Fig. 3, time T ₅ ). The generators 11-12 store at the outputs a constant voltage corresponding to the frequencies F _I3 and F _{D3 of} light flicker, which control the sources 15-16 (figure 2, the time interval T ₅ -T ₆ ).

When the fourth key 4 is opened, the fourth one-shot 25 generates a pulse that enters the S-input of the trigger 26 and turns it on, the first valve 27 opens. The signal from the output of the generator 18 through the open first valve 27 is supplied to the first 22 and second 23 single vibrators. Supplied to the calculator 17. The first monostable multivibrator 22 to the rising edge of a logic one signal on the output of the generator 18 produces a pulse which, via OR gate 29 when the signal is logic one at the output of generator 18 incremental frequency F _I3 of light flashes output from the first converter 13 via the multiplexer 8 is fed to a calculator 17, in which the value of the incremental F _{from the} frequency of light flickering is recorded. With a logic zero signal at the output of the generator 18, the decreasing frequency F _{D3 of} light flickering from the output of the second converter 14 through the multiplexer 8 is fed to the calculator 17. The second one-shot 23 at the trailing edge of the signal of the logical unit at the output of the generator 18 generates a pulse that is transmitted through the OR element 29 to a calculator 17, in which the value of the decrement F _F3 frequency of light flicker is recorded.

The calculator 17 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 block of 20 indicators, after which it generates a pulse (figure 2, time T ₆ ), turning off the trigger 11, as well as setting the device to its original state (circuit not shown).

Thus, the claimed device allows to increase the accuracy of determining the bandwidth of the receptive fields of the neurons of the visual system due to the simultaneous presentation of incremental and decrement frequencies of light flickers, which allows not to apply to long-term logical-semantic memory.

Information sources

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. - P.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. RF patent 2240029, IPC A61B 3/00. Device for determining the passband of receptive fields of neurons of the visual system. / A.G. Isaev, T.A. Lezhnina, V.V. Rozhentsov (RF). - Publ. 11/20/2004, Bull. Number 32.

Claims (1)

A device for determining the bandwidth of the receptive fields of the neurons of the visual system, containing the first, second generators of linearly varying voltage, a voltage-frequency converter, a light pulse source, an OR element, a computer, the first, second indicator blocks, a second pulse generator, a counter, a trigger, the first, the second valves, the first is the third one-shot, the first is the fourth keys and toggle switch, the outputs of the first, second mode switches are connected respectively to the inputs of the first, second generators, the output of the OR element is connected to the second input of the calculator, the first output of which is connected to the input of the first block of indicators, the second output is connected to the R-input of the trigger, the input of the voltage-frequency converter is connected to the output of the first generator, and the output to the input of the light pulse source and the counting input counter, the outputs of the first and second keys are connected respectively to the first, second inputs of the first mode switch, the normally closed output of the toggle switch is connected to the first input of the second valve, the output of the second pulse generator It is connected to the second inputs of the first and second valves, the first input of the first valve is connected to the trigger output, and the output is connected to the inputs of the first and second single 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-vibrator and the counter resolution input , the zeroing input of which is connected to the output of the third one-shot, and the output - to the input of the second block of indicators, characterized in that the first - third multiplexers, the second converter voltage-frequency, a second source of light pulses and a fourth one-shot, and the output of the first key is also connected to the first input of the first multiplexer and the second input of the second multiplexer, the outputs of which are connected respectively to the first and third inputs of the second mode switch, the output of the second key is also connected to the second input the first multiplexer and the first input of the second multiplexer, the output of the third key is connected to the third input of the first mode switch and the second input of the second mode switch, the fourth key output is connected to the fourth inputs of the first and second mode switches and the input of the fourth one-shot, the output of which is connected to the S-input of the trigger, the normally open output of the toggle switch is connected to the address inputs of the first, second multiplexers, the output of the second generator is connected to the input of the second voltage-frequency converter the output of which is connected to the input of the second source of light pulses and the second input of the third multiplexer, the first input of the third multiplexer is connected to the output of the first the forming voltage-frequency address input - with the output of the generator-second pulse, and the output - to the first input of the calculator.

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