Reliable chronic neural
recording from focal deep brain structures is impeded by insertion injury and
foreign body response, the magnitude of which is correlated with the mechanical
mismatch between the electrode and tissue. Thin and flexible neural electrodes
cause less glial scarring and record longer than stiff electrodes. However, the
insertion of flexible microelectrodes in the brain has been a challenge. A
novel insertion method is proposed, and demonstrated, for precise targeting
deep brain structures using flexible micro-wire electrodes. A novel electrode guiding system is designed
based on the principles governing the buckling strength of electrodes.
The proposed guide significantly increases the critical buckling force of the
microelectrode. The electrode insertion
mechanism involves spinning of the electrode during insertion. The spinning
electrode is slowly inserted in the brain through the electrode guide. The
electrode guide does not penetrate into cortex. The electrode is inserted in the brain without stiffening it by coating
with foreign material or by attaching a rigid support and hence the method is
less invasive. Based on two new mechanisms, namely spinning and guided
insertion, it is possible to insert ultra-thin micro-wire flexible electrodes in
rodent brains without buckling. I have demonstrated
successful insertion of 25 µm platinum micro-wire electrodes about 10 mm
deep in rat brain. A novel
micro-motion compensated ultra-thin flexible platinum microelectrode has been
presented for chronic single unit recording. Since manual insertion of the
proposed microelectrode is not possible, I have developed a
microelectrode insertion device based on the proposed method. A low power low
noise 16 channel programmable neural amplifier ASIC has been designed and used
to record the neural spikes. The ability to record neural activity during
insertion is a unique feature of the developed inserter. In vivo implantation process
of the microelectrode has been demonstrated. Microelectrodes were inserted in
the Botzinger complex of rat and long term respiratory related neural activity
was recorded from live rats. The developed microelectrode has also been used to
study brain activity during seizures.
In-vivo experimental
results show that the proposed method and the prototype insertion system can be
used to implant flexible microelectrode in deep brain structures of rodent for
brain studies.
| Identifer | oai:union.ndltd.org:purdue.edu/oai:figshare.com:article/11320169 |
| Date | 05 December 2019 |
| Creators | Muhammad Abdullah Arafat (8082824) |
| Source Sets | Purdue University |
| Detected Language | English |
| Type | Text, Thesis |
| Rights | CC BY 4.0 |
| Relation | https://figshare.com/articles/METHOD_OF_THIN_FLEXIBLE_MICROELECTRODE_INSERTION_IN_DEEP_BRAIN_REGION_FOR_CHRONIC_NEURAL_RECORDING/11320169 |
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