This pathophysiology diagram displays a Hodgkin-Huxley type simulation of neuronal network activity over a 1000 ms duration. The visual illustrates the periodic membrane potential (mV) oscillations of different neuronal types and compartments. The traces represent: regular spiking (RS), fast-spiking (FS), slow inhibitory (SI), and four compartments of an intrinsically bursting (IB) neuron (apical dendrite, basal dendrite, soma, and axon). Membrane potentials fluctuate between approximately -70 mV and +50 mV. Key educational concepts include firing patterns and synchronization. The RS and SI traces exhibit single spikes in phase with each other at approximately 15 Hz. In contrast, the FS neuron fires at double this frequency (30 Hz). The IB compartments demonstrate complex spatial dynamics; while the apical and basal dendrites, soma, and soma-proximal structures show single periodic spikes, the IB axon specifically exhibits characteristic high-frequency bursts of multiple spikes. The diagram serves as a model for understanding neural rhythms, such as parietal beta1 oscillations, and the influence of cellular architecture on action potential morphology.

This pathophysiology diagram illustrates the simulated electrophysiological response of a chemosensitive neuron from the Locus Coeruleus (LC) to electrical stimulation. Panel A displays the membrane potential (V, mV) responding to a hyperpolarizing pulse (-0.5 nA) and subsequent depolarizing pulse (0.6 nA). The trace shows an initial decrease in potential followed by a rapid burst of action potentials and spike frequency adaptation. Panel B details the postinhibitory rebound phase (3.0-4.5 s), highlighting the roles of the A-type potassium current (A) and T-type calcium current (T), the latter showing a significant influx correlating with a sharp rise in intracellular calcium concentration ([Ca2+]i). Panel C focuses on post-stimulation recovery, demonstrating the activation of M-type (M) and small-conductance calcium-activated potassium (SK) currents. The accumulation and gradual decay of [Ca2+]i modulate the firing frequency, showing that these ionic currents regulate the neuron's repetitive firing dynamics and recovery toward resting states.

Educational neurophysiology diagram illustrating current source density (CSD) and membrane potential (Vm) dynamics in a neuron model across three input scales (N=1, N=5, N=50). The figure is organized into four columns representing specific synaptic input locations: basal dendritic, perisomatic, oblique apical dendritic, and stratum lacunosum moleculare. Each row (A, B, C) depicts the increasing number of synaptic inputs. The top sub-panels show heat maps of CSD over time (X-axis) and spatial Y-position, where red indicates current sources and blue indicates current sinks (scale in pA). The bottom sub-panels show line graphs of membrane potential (Vm in mV) over a 30 ms duration. The data demonstrates that while intracellular potentials (Vm) summate with more inputs, extracellular signals (CSD) tend to cancel out and weaken for non-perisomatic inputs as N increases. This visual resource is used to teach concepts of bioelectricity, synaptic integration, and the biophysical principles underlying local field potentials in neurobiology and clinical neurophysiology.

This pathophysiology diagram provides a comparative visualization of neurons under 'Healthy neuronal function' versus 'Neurodegenerative conditions'. The upper panel depicts healthy neurons with intact morphology, functional autophagy, and healthy mitochondria, which facilitate 'Normal synapse firing'. Signal transmission is represented by continuous yellow arrows labeled 'Action potential propagation', indicating efficient neurotransmission. In contrast, the lower panel illustrates the impact of neurodegenerative disease on cellular physiology. The affected neuron exhibits structural changes, including a discolored (purple) soma and fragmented axon terminals. Key pathological features highlighted include depolarized mitochondria, the accumulation of soluble protein oligomers, and deacidified lysosomes. These cellular dysfunctions result in 'Decreased synapse firing' and 'Interrupted propagation', visually represented by a broken action potential arrow with a red burst symbol and a terminal block. The diagram serves as an educational summary of how impaired proteostasis and mitochondrial health lead to the breakdown of neuronal circuits in diseases such as Alzheimer’s, Parkinson’s, and Huntington’s.

This composite educational image illustrates the design and function of a flexible MXene-based electrochemical synaptic (FMES) device for neuromorphic computing and implantable prosthetics. Panel (a) presents a biological pathophysiology diagram of a synapse, showing neurotransmitter transmission from a presynaptic to a postsynaptic neuron. Panel (b) translates this into an anatomical/electronic diagram of the FMES device, featuring MXene electrodes on a PET substrate with an electrolyte medium; an inset shows the dynamic diffusion of hydrogen and sulfate ions. Panel (c) is a clinical/technical photograph showing the physical device—a small, flexible circular chip with labeled presynaptic and postsynaptic electrodes—held between fingers for scale (10 mm). Panel (d) provides circuit algorithms comparing high-resistance and low-resistance states, with corresponding voltage-distance plots for ionic 'read/write' operations. Panel (e) is a comparison chart showing the potentiation and depression behaviors of artificial synapses, plotting voltage against pulse number across various resistance states. This content demonstrates how bio-inspired electronics can simulate synaptic plasticity for advanced medical engineering applications like neural electrode arrays.

This pathophysiology diagram illustrates the role of magnesium in migraine pathogenesis and synaptic transmission. The top section compares a synapse under 'NORMAL Mg2+' conditions with one in 'HYPOMAGNESEMIA'. In the normal state, the NMDA receptor is shown with a magnesium block, regulating calcium (Ca++) entry. In the hypomagnesemia state, the block is absent, leading to 'NMDA-r Dysfunction' and increased ion flux. The diagram depicts key synaptic components including the presynaptic membrane with neurotransmitter vesicles, the postsynaptic membrane with AMPA and NMDA receptors, and glutamic acid signaling. The central flow shows how hypomagnesemia contributes to Cortical Spreading Depression (CSD), indicated on a brain illustration. Additional contributory factors shown include CGRP release, oxidative stress, neuroinflammation, and other trigger factors. The culmination of these processes is linked to 'migraine aura/attack,' represented by a facial illustration and a brain with focal excitatory waves. This diagram is designed for neurology and biochemistry education to explain the molecular mechanisms of magnesium deficiency in migraine development.

Educational scientific illustration and clinical micrograph set detailing cholinergic neurotransmission and its measurement via scanning electrochemical microscopy (SECM). (A) Pathophysiology diagram of a synapse showing a <100nm synaptic cleft, neurotransmitter vesicles, and postsynaptic receptors. (B) Light micrograph of cultured Aplysia ganglion neurons (Cell 1 and Cell 2). (C, D) Schematic of a nanoITIES pipette electrode and associated cyclic voltammogram demonstrating acetylcholine (ACh+) detection through ion transfer across a nanoscale interface. (E) Diagram of the experimental SECM setup, including a nano-positioning controller, potentiostat, and side-view optical microscope. (F) Real-time optical microscope image showing the spatial orientation of a stimulating pipette and nanoelectrode relative to a target synapse. (G) High-resolution scanning electron microscope (SEM) image of the nanoelectrode tip with a 15 nm radius. The composite illustrates high-precision electrochemical monitoring of neurotransmitter release dynamics at the single-synapse level, relevant to neurophysiology and diagnostic imaging research.

This anatomical diagram provides a lateral view of the human brain, specifically illustrating the cortical regions associated with the mirror neuron system. The line drawing highlights three key functional areas using shaded gray overlays and text labels: the premotor area in the frontal lobe, the primary motor cortex (M1) along the precentral gyrus, and the inferior parietal lobule in the parietal lobe. The diagram clearly depicts the complex surface anatomy of the cerebral cortex, including its gyri and sulci, which define the boundaries of these functional regions. The cerebellum is also visible inferiorly to the occipital and temporal lobes. This illustration is designed to teach the neuroanatomical basis of action-observation processing, demonstrating how the brain bridges visual perception of others' actions with its own motor representation. It is an educational resource suitable for neuroscience and clinical neurology, focusing on sensory-motor integration and the physiological mechanisms of social cognition.

Anatomical diagram of the human brain from a lateral view, illustrating the four major lobes of the cerebral cortex and their functional localizations. The frontal lobe (tan) is shown at the anterior aspect, containing the prefrontal cortex (decision making), Broca's area (speech), and the frontal eye field. Posterior to the central sulcus is the parietal lobe (green), which houses the primary sensory area. The temporal lobe (yellow) is situated inferior to the lateral sulcus, highlighting areas for language, olfaction, and hearing. The occipital lobe (purple) is located at the posterior pole, containing the primary visual area. Key neuroanatomical landmarks labeled include the central and lateral sulci, which define lobar boundaries. The diagram also identifies the primary motor area (red) for movement, Wernicke's area for sensory speech at the temporal-parietal junction, and subcortical structures including the cerebellum (coordinate movement) and brain stem (body basics), transitioning into the spinal cord.

This anatomical diagram provides a color-coded distribution map of the functional areas of the human cerebral cortex, viewed from a lateral perspective. The image illustrates the localization of key neurological functions across the four major lobes: frontal, parietal, temporal, and occipital. The frontal lobe (orange/green) includes the prefrontal area, pre-motor zone, primary motor cortex, and Broca's area (motor speech center). The central sulcus (labeled 'Central ditch') serves as the boundary between the motor areas and the somatosensory regions of the parietal lobe (blue), which contains the primary somatosensory cortex, taste zone, and somatosensory joint zone. The occipital lobe (yellow/orange) at the posterior pole depicts the visual cortex and visual union (association area). The temporal lobe (tan/red) highlights the primary auditory cortex, auditory complex, and Wernicke's area (sensory language area). This educational diagram is used to demonstrate the specialized topographical organization of the brain, facilitating the study of neuroanatomy and the clinical correlation between cortical lesions and specific functional deficits.

This multimodal anatomical and functional diagram illustrates the human 'autonomic connectome,' detailing the neural infrastructure of sympathetic and parasympathetic regulation. The central element is a circular network graph partitioned into two hemispheres: the upper represents the sympathetic nervous system and the lower the parasympathetic nervous system. Surrounding the center are colorful lines (edges) representing network-based statistics from functional MRI, gray matter morphometry, and white matter tractography. Edge width indicates connection effect size. The outer perimeter contains nodes corresponding to specific brain regions, such as the anterior cingulate cortex (ACC), insula (Ins), amygdala (Amg), and brainstem (BrStem). Node size is proportional to the Z-statistic importance of the region. Surrounding the central connectome are several 3D cortical surface reconstructions displaying color-coded parcellations that visualize hierarchical community structures. A color scale at the bottom indicates hierarchical community coherence (ranging from red to blue), while a size legend defines the regional Z-statistics. This educational visual explains the high-dimensional integration of disparate cortical and subcortical structures involved in autonomic homeostasis and sympathovagal balance.

This medical illustration depicts the Autonomic Nervous System (ANS) pathways connecting the brainstem to the heart. A sagittal section of the human brain shows the medulla oblongata as the origin for both parasympathetic and sympathetic innervation. The Vagus nerve (parasympathetic), color-coded in purple, is shown descending from the brainstem to the heart, where it branches to innervate the atria and ventricles; text annotations indicate its role in decreasing heart rate. The sympathetic cardiac nerves, color-coded in red, originate from the same region and follow a parallel descending path, branching across the cardiac tissue; text labels specify their role in increasing both heart rate and the force of contraction. The diagram illustrates the functional antagonism between the two branches of the ANS in cardiac regulation, highlighting the primary innervation sites at the sinoatrial node, atrioventricular node, and the myocardium.

This Comparison Chart illustrates the autonomic nervous system response in horses across different transport conditions. The figure consists of four line graphs (a-d) showing physiological modulations during three phases: pre-transport, during transport (up to 240 minutes), and post-transport (up to 90 minutes). Graph (a) depicts mean RR intervals (ms), showing a gradual increasing trend over time across all conditions. Graph (b) shows mean heart rate (HR in beats/min), generally reflecting an inverse relationship to RR intervals with a slow decline during transport. Graph (c) displays the Parasympathetic Nervous System (PNS) index, while Graph (d) shows the Sympathetic Nervous System (SNS) index. The study compares four experimental groups: air-conditioned full load (ATF), air-conditioned space load (ATS), non-air-conditioned full load (N-ATF), and non-air-conditioned space load (N-ATS). Statistical significance is indicated by Greek letter annotations (e.g., η, κ, λ, μ, γ) representing specific time-point differences and interactions between air conditioning, loading density, and time.

This diagnostic image shows a cross-sectional view of the L5 spinal cord segment, typical for neuroanatomical research. The section displays the characteristic butterfly-shaped central grey matter, demarcated by a yellow border, surrounded by peripheral white matter. The image demonstrates retrograde tracing of alpha-motoneurons (α-MNs) using True Blue fluorescence tracer, which was injected into the lateral gastrocnemius (LG) muscle. Two blue rectangular frames in the ventral horns highlight the bilateral distribution of labeled motoneurons. Below the main section, magnified inset views (100 µm scale) reveal the detailed morphology of these motoneurons, characterized by bright, fluorescent somata against a dark background, showing irregular polygonal shapes and emerging cellular processes. These α-motoneurons are essential components of the lower motor neuron system, and their visualization allows for the study of synaptic connectivity, such as glutamatergic VGLUT1 and cholinergic VAChT terminal density. The main section includes a 500 µm scale bar for anatomical orientation. This material is designed for advanced neuroanatomy and physiology education, focusing on spinal cord circuitry and motor unit innervation.

This medical visual consists of two parts: an anatomical diagram and a series of diagnostic images demonstrating spinal cord segmentation. Panel (a) is a schematic cross-section of the cervical spinal cord illustrating the segmentation protocol. Red regions of interest (ROIs) define the White Matter (WM) masks, located in the dorsal (D), ventral (V), and bilateral lateral (L, R) funiculi. Blue ROIs define the Grey Matter (GM) masks, positioned within the characteristic central 'butterfly' structure. Panel (b) presents Fractional Anisotropy (FA) maps derived from Diffusion Tensor Imaging (DTI) for nine human subjects (S1–S9). Each grayscale axial map is overlaid with the manually defined GM (blue) and WM (red) masks. The images demonstrate the variability in spinal cord morphology and pixel intensity across different individuals. The educational focus is on the localization of specific neural tracts and the application of quantitative MRI metrics to differentiate between spinal cord substructures. This material is relevant for neuroimaging research and the clinical assessment of pathologies like multiple sclerosis or spinal cord injury.

Anatomical diagrams illustrating the components of the monosynaptic stretch reflex arc in two experimental states. Both panels show a transverse section of the spinal cord (white and gray matter) connected to the gastrocnemius muscle via the sciatic nerve. Panel (a), labeled 'With stretch reflex', depicts an intact neural circuit: a sensory (afferent) pathway, colored green, carries signals from the muscle spindle to the dorsal horn, while a motor (efferent) pathway, colored orange/brown, carries impulses from the ventral horn back to the muscle. Black arrows indicate the direction of signal flow. Panel (b), labeled 'Without stretch reflex', demonstrates a disrupted circuit where the sciatic nerve has been severed, indicated by a red 'X' and the text 'Cut off'. This visualization highlights how the interruption of the peripheral nerve abolishes the reflex arc between the spinal cord and the effector muscle, commonly used in physiological studies to compare muscle response forces with and without neural feedback.

This pathophysiology diagram illustrates the glymphatic pathway and the structure of the blood-brain barrier (BBB) within the human brain. The main image shows a mid-sagittal section of the brain, color-coded to represent volume distribution: brain parenchyma (yellow, 80%), blood vessels (red, 10%), and cerebrospinal fluid (blue, 10%). Blue arrows indicate CSF flow from the subarachnoid space into the ventricles and along perivascular spaces. An inset provides a magnified cross-section of the BBB surrounding a central capillary. Key anatomical components identified in the inset include the endothelial cell layer with tight junctions, the basal lamina, and embedded pericytes. The outer layer consists of astrocyte endfeet, which are explicitly labeled as expressing aquaporin 4 (AQP4) water channels. The diagram demonstrates the physiological relationship between the vascular system and CSF movement, highlighting the cellular interface responsible for fluid transport and metabolic waste clearance in the central nervous system.

Educational composite figure demonstrating targeted drug delivery across the blood-brain barrier (BBB). Part A consists of a pathophysiology diagram and an in vitro model illustration. The diagram depicts the BBB structure, including astrocyte feet, tight junctions, the basement membrane, and the capillary lumen. Adjacent is a schematic of lactoferrin (Lf)-functionalized Fe3O4 magnetic nanoparticles interacting with receptors for transcytosis. Part B displays in vivo diagnostic imaging using axial T2* Magnetic Resonance Imaging (MRI) of rat brains. The images compare contrast enhancement between Fe3O4-Lf and non-functionalized Fe3O4 groups at pre-injection and 15-minute post-injection intervals. In the Fe3O4-Lf post-injection scan (image b), several brain blood vessels are highlighted with red dashed circles, showing significant signal darkening (hypointensity) due to the T2* shortening effect of the accumulated iron oxide nanoparticles. In contrast, the post-injection image for the bare Fe3O4 group (image d) lacks specific vascular enhancement, illustrating the efficacy of Lf-tagging for receptor-mediated transport across the BBB into the central nervous system.

This diagnostic comparison chart displays four panels of synchronized Electromyography (EMG) and Electroencephalography (EEG) tracings, illustrating different physiological states in a sleep-wake cycle. The panels represent: (a) Waking stage, (b) Slow-Wave Sleep 1 (SWS1), (c) Slow-Wave Sleep 2 (SWS2), and (d) Rapid Eye Movement Sleep (REMS). Each panel contains an EMG trace in the upper half and an EEG trace in the lower half. In the Waking stage, the EMG shows moderate tonic activity while the EEG is relatively low-amplitude. Transitions into SWS1 and SWS2 demonstrate a progressive increase in EEG amplitude and irregularity, characterized by higher voltage and slower waves (peaks and valleys), while the EMG maintains some activity. The REMS stage is marked by a distinctive EMG 'flatline' or muscle atonia (quiescence), contrasted with a desynchronized, lower-amplitude EEG signal. These visual biomarkers are critical for neurophysiological sleep staging, polysomnography research, and evaluating the effects of pharmacological interventions on sleep architecture and central nervous system activity.

This diagnostic graphic illustrates a 24-hour continuous EEG monitoring profile of a patient, likely in a state of disordered consciousness. The data is presented in six stacked subplots (a-f) representing different EEG components over time (in hours). Subplots (a), (b), (c), and (e) quantify the number of alpha, theta, and beta waves, and sleep spindles per 3-minute epoch, respectively. Subplot (d) indicates discrete markers for K-complex occurrences. Subplot (f) displays the percentage of slow-wave activity (SWA) per 20-second epoch, with horizontal thresholds at 20% and 50% corresponding to classical criteria for sleep stages 3 and 4. The profile demonstrates a lack of normal circadian rhythm, characterized by the absence of nocturnal concentration of sleep spindles and slow waves. There is no clear inverse correlation between sleep spindles and SWA, suggesting an atypical sleep-wake architecture. This method of continuous parametric assessment provides educational value in distinguishing between vegetative states (UWS) and minimally conscious states (MCS) through objective temporal analysis of electroencephalographic features.