Computational Study of Novel Thermal Effects on Neuronal Activity
Open Access
- Author:
- Kim, Tae Ken
- Graduate Program:
- Physics
- Degree:
- Doctor of Philosophy
- Document Type:
- Dissertation
- Date of Defense:
- October 05, 2020
- Committee Members:
- Steven Schiff, Dissertation Advisor/Co-Advisor
Reka Z Albert, Committee Member
Dezhe Jin, Committee Member
Carina Pamela Curto, Outside Member
Nitin Samarth, Program Head/Chair
Steven Schiff, Committee Chair/Co-Chair - Keywords:
- Neuroscience
Patch-clamp
Micromagnetic
Temperature
Sprague-Dawley rat
Transient suppression - Abstract:
- Many existing and novel neuromodulation techniques generate heat in the biological tissue. This can be from the electromagnetic wave depositing energy in the tissue, or from the joule heating of electrodes and coils placed near the neural tissue. The literature on the thermal effects is divided, with some reporting excitation, and some reporting inhibition. Most previous studies investigated the steady-state behavior of the neuron. As such, there is a lack of understanding of the transient response of neurons immediately following the environmental change, such as application and removal of external stimulation. I analyzed micromagnetic stimulation experiments on Layer 5 pyramidal neurons of rats in vitro, where detailed temperature measurements were recorded. Limiting the tissue's temperature increase to 1°C limited the coil's field strength, and no magnetic effects were detected. However, I observed a transient suppression of activity at the onset of stimulation and hyperactivity at the removal of stimulation. Through numerical modeling, I explored the biophysical mechanisms behind this transient phenomena and showed that thermal increases of pump rate and reversal potential can explain these effects. I also showed that an accurate model-based description of the transient effects is only possible using models that ensure particle conservation between intra and extracellular space. Using the same modeling framework, I also predicted the existence of high temperature silencing created by the Nernst potential's temperature dependence, and the role of chlorine cotransporters NKCC1 and KCC2 in the steady-state thermal response of neurons.