SU234605A1 - MICROELECTRODE HOLDER - Google Patents

Description

Microelectrode holders comprising a housing with a microelectrode fixed in it and equipped with a shaped washer threaded bushing for trepanning the opening of the skull are known.

However, these holders do not provide sufficiently stable and accurate fixation of the microelectrode required for recording the electrical activity of an individual neuron for a long time. There is also no provision for adjusting the GoTubin of screwing in the sleeve to prevent pulsation of the exposed portion of the cortex, which degrades the quality of recording in a chronic experiment.

The proposed microelectrode holder is distinguished from the known ones in that a removable sleeve is installed in the threaded sleeve, the distal part of the orifice of which is filled with a soft plastic substance, for example, clay. This ensures accurate fixation of the microelectrode in a given position and at the same time isolates the exposed brain region from the external environment, as a result of which the accuracy and reliability of recording the electrical activity of individual brain neurons is increased and the maximum duration of the experiment is increased.

a trigger 1 with a microelectrode 2 fixed in it . A sleeve made of a material that is neutral to living tissue, such as organic glass, is screwed into the burr hole in the skull 8 of the experimental animal. To increase the tightness, the sleeve 6 is additionally rigidly fixed with a layer of insulating material 9, for which self-hardening plastic can be used, for example, styracryl.

The lower end of the microelectrode is inserted through the through-hole of the sleeve into the thickness of the cerebral cortex 10; the upper end is attached to contact 11 in any convenient way, for example, by means of an elastic rubber tube 12, tensioned on the microelectrode 2 and the contact.

In the upper (not shown in the drawing) part of the housing is a known mechanism for remotely moving the microelectrode. The wire 13, which connects the contact with the recording device, is led out of the housing 1 at any convenient place, for example through a gap between the housing and the ring 3.

An optional removable sleeve 14, which is screwed into the threaded sleeve 6 with a thread cut into its thickened part 15 (head). The lower part of the opening 16 of the removable sleeve 14 is filled with a layer 17 of a plastic substance, which can be used as agar, clay, paraffin and other neutral substances. Microelectrode 2 passes through this layer, which, having elasticized the microelectrode, ensures its very accurate fixation both in the initial position and when moving deep into the cortex. Layer 17 also serves to tightly close the opening 16 and prevent the opening of the detachable sleeve 14 into the exposed area of the brain and thereby allowing the same animal to be tested without worsening the condition of the examined cortical tissue for 9-10 days. Longer registration is impossible due to the formation of a dense connective tissue film under the sleeve, which prevents the passage of the microelectrode.

The proposed microelectrode holder allows one to perform long-term chronic experiments on the type of sharp on the same animal and to avoid several complicated operations on craniotomy.

To suppress the pulsation of the studied area of the brain, which reduces registration accuracy due to the displacement of the microelectrode tip from the detected cell, it is sufficient to screw the removable sleeve 14 deeper into the threaded sleeve 6.

In order to conduct research, it is necessary to repeatedly remove the microelectrode from the animal's skull (for example, when it is replaced). In the intervals between the experiments, it is also necessary to remove the microelectro 2 along with the body / in order to provide the animal with rest and feeding. To do this, simply lower the screws 4 and remove the housing with the microelectrode. Upon subsequent installation of the housing into the working position, it, together with the ring 3, is rotated relative to the initial position. In this case, due to the eccentricity of the ring hole, the microelectrode is displaced relative to the initial position and fixed by a layer 17 of a plastic substance.

After repeated installation of the microelectrode, the tightness of the layer is broken. To restore it, it is necessary to refill the guide hole 16 with a plastic substance. Due to the use of the removable sleeve 14, this operation is very simple: the removable sleeve is unscrewed from the threaded sleeve 6 and removed from it

elastic material. Then, under aseptic conditions, the lower part of the opening 16 is again hermetically filled with plastic material, after which the removable sleeve is installed in its original place.

To speed up this operation, you can prepare in advance the same detachable sleeve and quickly replace the first sleeve with it. When unscrewing the removable sleeve through the hole 7 of the sleeve 6, you can observe a magnifying glass using a magnifying glass

for the physiological state of the investigated area of the brain. Through the same hole, you can enter (apply) various pharmacological agents. When the removable sleeve 14 is unscrewed, a cork is screwed into its place, tightly closing the opening of the sleeve 6.

Subject invention

A microelectrode holder containing a threaded sleeve equipped with a shaped washer

under the trepanation opening of the skull and the body with a microelectrode fixed in it, characterized in that, in order to increase the accuracy and reliability of recording the electrical activity of individual neurons of the brain

the brain by fixing the electrode in a predetermined position and increasing the maximum duration of the experiment, a removable sleeve is installed in the threaded bushing, the distal opening of which is filled with a soft plastic substance, such as clay.