Emma Krivoshein
Major/Minor: Psychology/Neuroscience
Title: The Relationship Between Norepinephrine Neuromodulation and Stability of Global Brain States Studied Using Electroencephalography and Trans-cranial Magnetic Stimulation
Abstract: Recent research investigating the neural dynamics of consciousness has emphasized that stability of brain states is important for revealing both the contents and overall level of consciousness (Wang, 2008). However, the underlying neural mechanisms that modulate stability are not well understood (Perl et al., 2020). Norepinephrine, a slow-acting neurotransmitter, modulates the excitability of neural networks and thus may play a role in controlling stability of specific brain states (O’Donnell et al., 2012). Norepinephrine levels can be reliably indexed by pupil diameter because the primary source of norepinephrine, the locus coeruleus, projects directly to the pupil dilator muscles (Joshi et al., 2016). Past studies in this topic have involved correlating neuromodulator activity with tasks, but not many studies have used perturbation of the brain to observe the effects of neuromodulation on stability. In this study, we perturbed the brain at resting state with trans-cranial magnetic stimulation and recorded the brain’s response to stimulation with electroencephalography. We also recorded pupil diameter to index norepinephrine levels directly before, during, and after stimulation. We aim to establish whether NE acts as a stability modulator by assessing whether stability covaries with pupil size. Such a relation would suggest that norepinephrine plays a crucial role in influencing neural dynamics that are relevant to consciousness.
