This pathophysiology diagram illustrates the neural circuitry involved in tonic phase apnea during seizures, using a rodent brain model as a surrogate for human epilepsy research. The schematic identifies two primary seizure initiation sites: the Cortex (indicated by a lightning bolt for electrical/ictal activity) and the Inferior Colliculus (IC) (indicated by a speaker icon for audiogenic triggers). Both regions project downstream to an undetermined neural substrate in the brainstem, represented by a black box with a question mark. This brainstem region is shown to recruit motor neurons (MN) that directly influence the 'Breathing Muscles' (depicted as a rib cage), illustrating the final common pathway for seizure-induced apnea. A red arrow signifies a feedback loop or seizure spread from the brainstem/IC back to the cortex, which can reactivate cortical ictal activity. The diagram serves as an educational tool to distinguish between cortical-onset and brainstem-mediated seizure components and their respective roles in respiratory dysfunction and sudden unexpected death in epilepsy (SUDEP) research.

This pathophysiology diagram illustrates the interconnected pathways of epileptogenesis and cognitive deficits following seizure activity in the brain. The visual flow begins with a sagittal brain illustration highlighting a focal point of seizures, which triggers three primary cellular events: mitochondrial ROS increase, glial cell activation (microglia and astrocytes), and neuronal dysfunction. These events lead into three distinct pathophysiological cascades. The first cascade involves mitochondrial oxidative stress, mtDNA damage, membrane potential (ΔΨm) decline, and Ca2+ accumulation, resulting in mitochondrial dysfunction and neuronal apoptosis. The second cascade details neuroinflammation driven by pro-inflammatory mediators (IL-1β, IL-6, TNF-α), leading to neurodegeneration and neural death. The third cascade focuses on disbalanced neurotransmission, characterized by increased glutamate (Glu) and decreased GABA and acetylcholine (ACh), leading to excitotoxicity. These three pathways are shown to be bidirectional and mutually reinforcing, ultimately converging to drive the clinical outcomes of epileptogenesis and cognitive impairment. The diagram is intended for medical education on the molecular and cellular mechanisms of chronic epilepsy.

This pathophysiology diagram illustrates the neural circuitry and mechanisms of seizure-induced cardiorespiratory dysfunction leading to Sudden Unexpected Death in Epilepsy (SUDEP). The primary visual features a sagittal view of the human brain highlighting the cortex, striatum, hippocampus (HC), amygdala, and hypothalamus. Red (afferent) and green (efferent) pathways show connections between these higher cortical/limbic regions and the central autonomic network in the brainstem. A magnified inset of the brainstem details specific regulatory nuclei: the pontine respiratory group (PRG) in the pons, and the ventral respiratory group (VRG), dorsal respiratory group (DRG), nucleus ambiguus (NA), vagus nucleus, and nucleus tractus solitarii in the medulla. The diagram maps how seizure activity disrupts these cardioregulatory and respiratory centers, leading to peripheral autonomic failure. The lower section depicts the clinical outcomes of this dysfunction: apnea in the lungs, and asystole or arrhythmia in the heart, symbolized by a lightning bolt indicating acute cardiorespiratory collapse.

This pathophysiology diagram illustrates the progression of epilepsy through three stages: Normal, Epileptogenesis, and Epilepsy, focusing on neural network activity, dendritic spine morphology, and underlying molecular changes. The top row depicts the evolution of electrical activity from low-amplitude, irregular baseline fluctuations (Normal) to increased amplitude oscillations (Epileptogenesis, red) and finally to high-frequency, paroxysmal spike-and-wave discharges characteristic of seizures (Epilepsy, blue). The middle row shows anatomical changes in dendritic spines following an initial 'Injury'. The 'Normal' stage displays healthy mushroom-shaped and thin spines. 'Epileptogenesis' shows a reduction in spine density and morphological atrophy. The 'Epilepsy' stage demonstrates aberrant spine regrowth or remodeling, showing thickened, dysmorphic spines. The bottom section lists key molecular drivers of this progression within overlapping oval nodes, including neuroinflammation, increased BDNF and mRNA levels, alteration of the actin cytoskeleton, reduced alpha-actin-2, decreased fibronectin-integrin binding force, and loss of drebin. This illustration is intended for medical education regarding the neurobiological mechanisms of seizure development and synaptic plasticity.