University of Twente Student Theses
Computational models to investigate the effect of weak electric fields on the (de)synchronization of neurons
Bosman, M. (2024) Computational models to investigate the effect of weak electric fields on the (de)synchronization of neurons.
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| Abstract: | Deep brain stimulation (DBS) is effective in treating the motor symptoms of Parkinson’s disease (PD), however, its therapeutic mechanism is still under discussion. We hypothesized that weak electric fields desynchronize cortical neurons in the motor cortex, thereby contributing to the therapeutic mechanism of DBS. For low-frequency brain stimulation (i.e. TACS), experimental and computational studies showed desynchronization by low-amplitude electric fields. In this study, we used computational models to investigate under which conditions neurons synchronize and desynchronize when an alternating weak electric field is applied. We simulated a simple oscillator model (Stuart-Landau model) to predict the behaviour and synchrony of a neural population. The effect of an external drive on the amplitude of this oscillator was investigated. To study the effect on single cells we used morphologically realistic neural models and simple two-compartment models with a synaptic input and an applied external electric field. The effect of stimulation settings on the entrainment to this applied electric field and synaptic input was studied. The Stuart-Landau model showed that desynchronization can occur at high stimulation frequencies, similar to those used in DBS. For specific parameter settings, weak fields decreased entrainment, and strong fields increased entrainment. However, the relationship between stimulation amplitude and (de)synchronization is very sensitive to variations in stimulation frequency, intrinsic frequency and their ratio. The two single-cell models showed synchronization with respect to the stimulation frequency. They also showed constant synchrony with respect to the beta frequency, except for the two-compartment model with a constant input, where a desynchronization to the beta frequency was found. However, this was likely due to a very unrealistic neuron model that is very susceptible to noise. The hypothesis cannot be rejected or accepted using these models. The single-cell models in their current form are insufficient to model the baseline state (oscillatory synchrony that is not due to external inputs). However, including network interactions in this model enables future research to more accurately investigate (de)synchronization dynamics. |
| Item Type: | Essay (Master) |
| Faculty: | TNW: Science and Technology |
| Subject: | 44 medicine |
| Programme: | Biomedical Engineering MSc (66226) |
| Link to this item: | https://purl.utwente.nl/essays/103752 |
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