Small Animal EEG Electrode Unit with Vertical Insulating Tubes

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Solution Overview

Problem

Conventional electroencephalogram (EEG) and functional MRI (f-MRI) measurement techniques for small animals, such as rats, face challenges in detecting multiple EEG signals due to limited brain surface space and high impedance issues, limiting the effectiveness of simultaneous EEG and f-MRI measurements.

Innovation Solution

An electroencephalogram electrode unit for small animals featuring a base with multiple through holes, each housing a movable insulating tube with an electrode section and a conductive paste, minimizing metallic contact and allowing for increased electrode density, enabling simultaneous EEG, f-MRI, and other measurements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If conventional metal or carbon electrodes are placed and fastened to the brain surface of small animals, then the electrodes can be secured in position, but the number of electrodes is limited due to small brain surface area and impedance cannot be maintained low

Engineering Contradiction:
Improvenumber of electrodesVSAvoidbrain surface area
Core Design Contradiction:
Quantity of substanceVSArea of stationary object

Solution Approach 1:

The electrode structure transitions from a conventional planar configuration to a three-dimensional arrangement by inserting electrodes through holes in the base that contacts the brain surface. This vertical dimension allows multiple electrodes to be densely packed within a small footprint area, significantly increasing the number of electrodes that can be accommodated on the limited small animal brain surface.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The electrode assembly employs a nested structure where the electrode is inserted into the through hole of the base, with the electrode section positioned within the paste-filled hole. This nesting approach maximizes space utilization and allows for high electrode density while maintaining a compact overall structure suitable for small animal applications.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Reliability

If conventional electrodes are fastened to the brain surface, then the electrodes can be secured, but high impedance is generated between the scalp and the electrodes

Engineering Contradiction:
Improveelectrode contact stabilityVSAvoidimpedance
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

A conductive paste is introduced as an intermediary substance between the electrode section and the brain surface (scalp). This paste fills the through hole and creates an optimal conductive interface, reducing contact impedance and improving signal quality while maintaining stable electrode positioning.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The through holes in the base are pre-filled with conductive paste before electrode insertion. This preliminary preparation ensures that when the electrode is inserted, it immediately makes contact with the conductive paste, establishing low-impedance contact with the brain surface from the outset and ensuring reliable signal acquisition.

Inventive Principle:
Principle #10Preliminary action

3Device complexity

If a single electrode is used for EEG measurement, then the measurement system is simple, but electroencephalogram can be detected only partially and is not effective for entire brain study

Engineering Contradiction:
Improveelectrode configurationVSAvoidbrain activity coverage
Core Design Contradiction:
Device complexityVSLoss of information

Solution Approach 1:

The EEG measurement system is segmented into multiple independent electrode channels distributed across the base. Each through hole accommodates an individual electrode, allowing simultaneous recording from multiple brain regions. This segmentation enables comprehensive coverage of the entire brain surface while maintaining manageable system complexity through modular electrode design.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP2561806B1Electroencephalogram electrode unit for small animals and measurement system using same
Publication Date: 2019.06.12 TOHOKU UNIV
  • EP2561806B1 patent drawingFigure 1(A)~1(B)
  • EP2561806B1 patent drawingFigure 2(A)~2(B)
  • EP2561806B1 patent drawingFigure 3(A)~3(B)

AI summary

An electroencephalogram electrode unit for small animals for maximally detecting the EEG signals from the limited brain surface space of small animals is disclosed. The electroencephalogram electrode unit 1 for small animals includes: a base 2 that covers the scalp or brain surface of a small animal and has a plurality of through holes; and a plurality of electrodes 3. Each of the plurality of electrodes 3 is inserted into each of the plurality of through holes 2a, and each of the plurality of electrodes 3 is equipped with an insulating tube 4, an electrode section 6 disposed within the tube 4, an extraction conducting wire 7 that is connected to the electrode section 6 and extracts the EEG signal to outside, and a paste 8 that is filled within the tube. The tube 4 is installed in the through hole 2a in a manner of standing upright from the scalp or brain surface, and the electrode section 6 is formed in the form of a wire and is disposed, in a manner of standing upright from the scalp or brain surface, within the paste 8 filled within the tube 4.