SU728844A1 - Method and apparatus for determining localisation of brain functions - Google Patents

Description

changes when structures are turned off during an animal's behavioral act.

This is achieved by orienting along the coordinates of the formations to be turned off and implanting a fixing device, including an ultrasonic emitter, on the animal's skull, and at the moment of performing the behavioral act by the animals, they are exposed to ultrasound.

A device for carrying out the method is provided with a device for fixing the body on the skull of an animal and a pressure cap to limit the vertical movement of the radiator, and the body is designed as a hollow cylinder whose inner diameter corresponds to the outer diameter of the ultrasonic radiator.

The drawing shows a device for carrying out a method for determining the localization of brain functions.

It has a housing 1 made in the form of a hollow cylinder, the inner diameter of which corresponds to the outer diameter of the ultrasonic transducer, filled with sound-conducting fluid, and the ultrasonic radiator 2. The device is equipped with a device 3 for attaching the housing to the skull of an animal and a pressure cap 4 to limit the vertical movement of the radiator. The cylindrical body 1 has a side 5.

The method is carried out as follows.

The experimental animal is implanted with a device over the left optic tract. The coordinates of the area to be turned off:,, the coordinates of the stereotactic atlas, where F is the frontal direction from the zero plane; L is the lateral direction from the sagittal schva; Z is the height determined from the zero plane. All sizes are in millimeters.

Electrodes are also implanted to control the effect of deactivation and to control the mode of adaptation according to electrophysiological parameters:

a) cortical electrodes (silver on wire in lacquer insulation with a diameter of 0; 3 mm) - To the visual and motor areas of the cortex with coordinates:

visual cortex F-7, L ± 3 motor cortex F 22, L ± 5 to the left and to the right of the sagittal scar

b) the subcortical electrode (bipolar electrode; nichrome wire in lacquer insulation with a diameter of 0.1 mm) —in the optic tract with coordinates F 7, L 11, Z 10.

The device is implanted as follows.

In the midline, the skin is incised, the muscle is separated, the section of the cranial bone above the structure to be turned off is exposed. Using the micromanipulator pointer on the cranial bone, a point is located above the left optic tract with coordinates, L 11. A circle with the center at the specified point and with a diameter equal to the diameter of the device case 1 is drawn on the animal's skull. Make trepanation hole found diameter. Install the device over the burr hole, fix it to the skull with scouriacryl and screws 6 and align it in the horizontal plane during the fixing process by aligning the upper end with the tip of the pointer moving in the horizontal plane using a micromanipulator.

Next, a temporary adaptation mode is introduced, which is from the moment the animal device is implanted on the skull to the moment ultrasound is inserted into the brain, a time interval is taken that ensures that the animal leaves the anesthesia and restores the normal functioning of the brain to the operational level. , which is determined by electroencephalographic indicators of the amplitude-frequency characteristics of the electroencephalogram of the values that exist in the norm (amplitude of 20-30 µV, reaction synchronization during 5-10 ° / time of registration) and conditional reflex index, when the level of the right conditional reflexes reaches the starting level (85%). At the end of the temporary adaptation mode, the left optic tract of the awake animal is switched off after three days and the functions of conducting visual information along the visual tract are studied. For this, the animal is placed in an experimental chamber. The electrodes are connected through a connector using a flexible cable 7 to the input of a biopotential amplifier, and the output of the amplifier is connected to an oscilloscope. In the cylindrical body 1 of the device is placed an ultrasonic emitter 2 connected by a flexible cable 7 with an ultrasonic generator 8.

The animal is presented with a target inserted in the left and right field of view. Investigate his active defensive reflex to show a target.

The results are presented in table. one.

Then, ultrasound is delivered with the following parameters: intensity 65 W / cm 2, pulse duration 10 ms, frequency 50 pulses / s, irradiation time

1 MINUTE.

After 1 min after irradiation, the effect of turning off the left optic tract is monitored by the absence of evoked potential in the left optic tract on retinal stimulation with flashes of light lasting 1 ms at a frequency of 0.5 imp / s. 2 minutes after irradiation, the active-defensive reflex of the target presentation is re-examined. The results are presented in table. 2

Then, 5 minutes after irradiation, the boundaries of the visual fields are determined when moving the target from the central meridian.

The results are presented in table. 3

Thus, the data obtained during the animals performing a behavioral act after turning off the left optic tract suggests that only after the target crosses the zero meridian, a conditioned reflex reaction to the target occurred. Consequently, the function of transmitting information from the left half of the field of view of both eyes is localized in the left optic tract.

The proposed method using the device allows detecting the dynamics of phase states of behavior in the first minutes of shutdown when animals perform a behavioral act, which gives additional information about the localization of functions of brain structural structures and increases the reliability of the information obtained about the localization of brain functions by conducting an experiment on awake non-narcotized animal in the course of performing a behavioral act.

Area,

The number of presentations of the pollen I presentation

10 10

Left field of view Right field of view

Moving from the central meridian, degrees

On the left

 to the right

+ 20

+ 15

+ 10

ABOUT

-five

-ten

-15

Claims (2)

1. A method for determining the localization of brain functions, based on turning off deep-lying brain structures using focused ultrasound pulses, characterized in that, in order to identify the nature of functional changes when the structures turn off during the behavioral act, the animals are oriented along the coordinates of the formations to be turned off and implanted on the skull of the animal, a fixation device, including an ultrasonic emitter, and at the time the animal performs a behavioral act, azvukom. 2. A device for carrying out the method according to claim 1, comprising a housing filled with a sound-conducting fluid and an ultrasonic emitter, characterized in that it is equipped with a fixture for securing the Table 1 T Number of reflex responses 10 10 table 2 Table 3 The presence or absence of a reflex response THERE IS there is there is there is the body on the skull of the animal and the pressure cap to limit the vertical movement of the radiator, and the body is made in the form of a hollow cylinder, the inner diameter of which corresponds to the outer diameter of the ultrasonic radiator. , Sources of information taken into account in the examination 1.Karpenter M.V., Whittier J. R. "Study for methods for producing experimental system reference to stereotaxic technique. J. Compar. Neurol. 1952, v. 97.1, pp. 73-117. 2.Avir, V.M., Adrianov, O.S., Vykhodtseva, NI, Gavrilov, L.R., Mehring, T.A., Syrotyuk, M.G. Destruction of deep brain structures using focused ultrasound. Journal of Higher Nervous Activity. 1971, t. XXI, no. 5, s. 1110-1113. (prototype).