AI-Based Learning Experiences of Nursing Students: A Qualitative Study.

Serotonin (5-HT) is a key neurotransmitter that plays a vital role in regulating both central and peripheral nervous system functions. Its depletion has been strongly associated with the pathogenesis of several debilitating neurological disorders, including Parkinson’s disease [], anxiety, major depressive disorder [], sleep disturbances [], and migraine []. In migraine patients, 5-HT levels are significantly reduced during attacks, and their restoration has been shown to mitigate pain [,]. Substantial evidence highlights the pivotal role of 5-HT in migraine pathophysiology, influencing both electrophysiological and molecular mechanisms through the peripheral [] and central sensitization [–] of the trigeminovascular pathway. However, the precise mechanisms by which 5-HT modulates this pathway remain incompletely understood. Migraine is a multifactorial disorder characterized by diverse clinical manifestations and variable susceptibility among individuals []. While genetic, environmental, and lifestyle factors [–] have been implicated, the intrinsic properties of primary sensory neurons that may underlie this variability remain poorly defined. In this context, we introduce the concept of of the trigeminovascular system, referring to the inherent excitability and responsiveness of TG neurons at the cellular level. This susceptibility reflects the baseline propensity of TG neurons to undergo sensitization, whereby 5-HT depletion may enhance overall neuronal susceptibility and predispose neurons to exaggerated responses to nociceptive stimuli. Therefore, we aimed to define intrinsic neuronal susceptibility at the cellular level by characterizing the electrophysiological properties of first-order TG neurons under 5-HT depleted conditions. The trigeminovascular pathway, a central component of migraine pathophysiology, involves multiple levels of processing, with TG neurons serving as first-order neurons. These neurons can be broadly classified into small-to-medium (SM) and large (L) subtypes, which differ in their functional roles in nociceptive and somatosensory signaling. While SM neurons are predominantly nociceptive [,], L neurons exhibit more heterogeneous functions, including both nociceptive and non-nociceptive properties []. Electrophysiological features, particularly action potential (AP) waveform characteristics, are widely used to distinguish these functional phenotypes [–]. Recent identification of large-sized Ah-type myelinated nociceptive neurons further highlights the complexity and dynamic nature of TG neuron involvement in pain processing [,].