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Author:Turunen, Teemu
Title:Laitteisto ERG-signaalin samanaikaiseen rekisteröintiin näköaistinsolukerroksesta sekä verkkokalvon yli
Device for simultaneous measurement of ERG-signal from photoreceptor layer and across the retina
Publication type:Master's thesis
Publication year:2011
Pages:vii + 64      Language:   fin
Department/School:Lääketieteellisen tekniikan ja laskennallisen tieteen laitos
Main subject:Lääketieteellinen tekniikka   (Tfy-99)
Supervisor:Koskelainen, Ari
Instructor:Vinberg, Frans ; Heikkinen, Hanna
Electronic version URL: http://urn.fi/URN:NBN:fi:aalto-201207022758
OEVS:
Electronic archive copy is available via Aalto Thesis Database.
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Location:P1 Ark Aalto  1527   | Archive
Keywords:retina
photoreceptor
light response
CNG-channel
verkkokalvo
näköaistinsolu
valovaste
TERG
LERG
CNG-kanava
Abstract (eng): Absorption of light by photoreceptors in the retina causes a series of biochemical reactions where the information carried by light is transformed into electrical cell level signals.
The resulting changes in the voltage profile of the extracellular space can be measured with the electroretinogram technique (ERG).

The ERG signal originating in the photoreceptors can be registered from isolated retina with two different methods: By isolating the photoreceptor response pharmacologically and registering the potential difference across the whole retina (transretinal ERG) or by registering the potential difference with microelectrodes only from the desired cell layer (local ERG).

In this master's thesis, a setup was built for simultaneous measurement of LERG and TERG responses.
The device was tested with experiment protocol where the LERG-responses from the outer segment and the TERG responses from the photoreceptors were compared.

Based on the results it was stated that the LERG technique can be used for the quantitative studies of photoreceptor function.
When the TERG and LERG responses where compared, no significant differences were found in the rising velocity, recovery kinetics, time of the peak amplitude or in the relative amplitudes of the responses.
The most notable difference was the fast transient wave in the TERG responses to bright light stimulus.
The experiments conducted in this study confirm that it originates in the inner segment of the photoreceptors.
Abstract (fin): Valon absorptio verkkokalvon näköaistinsoluissa saa aikaan monivaiheisen biokemiallisten reaktioiden sarjan, jossa valon sisältämä tieto muunnetaan solutason sähköisiksi signaaleiksi.
Näiden signaalien aiheuttamia muutoksia verkkokalvon soluvälitilan jänniteprofiilissa voidaan tutkia elektroretinogrammi -tekniikalla (ERG).

Näköaistinsolujen ERG-signaalia voidaan rekisteröidä eristetystä verkkokalvosta kahdella tavalla: Erottamalla näköaistinsolujen vaste farmakologisesti ja rekisteröimällä potentiaalieroa koko verkkokalvon yli (TERG) tai rekisteröimällä potentiaalieroa mikroelektrodeilla vain tutkittavasta solukerroksesta (LERG).

Diplomityössä suunniteltiin ja rakennettiin laitteisto, jolla voidaan rekisteröidä samanaikaisesti LERG- ja TERG-vasteita.
Laitteistoa testattiin koeohjelmalla, jossa verrattiin ulkojäsenkerroksesta rekisteröityjä LERG-vasteita ja näköaistinsolujen TERG-vasteita.

Tulosten pohjalta todettiin, että LERG-tekniikka voidaan käyttää näköaistisolujen toiminnan kvantitatiiviseen tutkimukseen.
LERG- ja TERG-vasteita vertailtaessa huomattiin, etteivät vasteiden nousunopeus, katkaisukinetiikka, nousuaika huippuarvoon ja suhteelliset amplitudit poikenneet toisistaan merkittävästi.
Suurin eroavaisuus oli voimakkailla valostimuluksilla TERG-vasteisiin muodostuva nopea transientti aalto.
Tässä työssä tehdyt kokeet vahvistavat, että kyseinen komponentti syntyy näköaistinsolujen sisäjäsenkerroksessa.
ED:2012-02-02
INSSI record number: 43911
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