Introduction to Neurophysiology Neurophysiology serves as a vital cornerstone of physiological science, focused specifically on decoding the multifaceted electrical and chemical dynamics of neurons and their communicative networks. This field aims to illuminate the precise biological mechanisms that govern all nervous system operations, spanning from elementary autonomic reflexes to the highly sophisticated cognitive landscapes of […]
Nociceptive Reflex: Neurophysiological Mechanisms and Clinical Implications Kieran A. Smith1*, Maria C. Corrêa2 and David E. Wigmore3 1Department of Neuroscience, University of Bristol, Bristol, UK 2Department of Neuroscience, University of São Paulo, São Paulo, Brazil 3Department of Neurology, University of Oxford, Oxford, UK Abstract Nociceptive reflexes are protective responses to potentially tissue damaging stimuli. They […]
Overview of the Ten-Twenty System The Ten-Twenty system, also frequently designated as the International 10-20 System, serves as the primary and most widely recognized protocol for the placement of electrodes on the human scalp during electroencephalography (EEG) procedures. This system provides a rigorous framework for neurophysiologists and clinicians, ensuring that the electrical activity of the […]
The Fundamental Nature of Texture Perception Texture perception represents a sophisticated cognitive and sensory process that enables humans and other biological entities to interpret and categorize the physical properties of environmental surfaces. This capability is not merely a secondary sensory function but is fundamentally critical for survival and daily functioning, influencing how we interact with […]
Introduction to Event-Related Potentials (ERP) In the field of cognitive neuroscience, Event-Related Potentials (ERP) represent one of the most vital methodologies for observing the human brain in action. An ERP is defined as a measured brain response that is the direct result of a specific sensory, cognitive, or motor event. More formally, as described by […]
Overview of Basket Cell Morphology and Classification The basket cell represents a fundamental class of GABAergic interneurons, primarily distinguished by its unique axonal architecture and its specialized role in providing perisomatic inhibition to principal neurons. Found predominantly within the neocortex and the hippocampus, these cells are named for the characteristic “baskets” their axonal terminals form […]
Introduction and Definition of Nerve Conduction Nerve conduction, fundamentally defined as the process by which electrical signals are transmitted along the length of a nerve cell, or neuron, represents the core mechanism of communication within the nervous system. This highly sophisticated biological process is essential for the rapid and accurate relaying of information, governing everything […]
Introduction and Core Definition of the Negative Afterpotential The Negative Afterpotential, a critical component of cellular excitability in neuroscience and muscle physiology, refers to the transient period of increased negative membrane potential that immediately follows the successful propagation of an Action Potential (AP). While the term itself might seem counterintuitive—a “negative” potential resulting in a […]
Introduction and Definition The Summating Potential (SP) is a critical electrophysiological measurement in auditory science, representing a sustained, slowly changing electric potential generated within the cochlea in response to acoustic stimulation. Unlike the rapidly oscillating Cochlear Microphonic (CM) or the transient Auditory Nerve Action Potential (AP), the SP is fundamentally a direct current (DC) shift […]
Introduction and Definition of Sensory Evoked Potential (SEP) The Sensory Evoked Potential, frequently abbreviated as SEP, represents a specialized class of electrical brain activity recorded in response to external sensory stimulation. Fundamentally, an SEP is a neurophysiological measure captured by highly sensitive recording electrodes precisely affixed to a person’s scalp, reflecting the brain’s immediate electrical […]
Introduction and Definition The Triune Brain model, a framework posited by the American doctor and neurophysiologist Paul D. MacLean in the mid-20th century, describes the human brain as having evolved sequentially in three distinct, layered structures. This view suggests that the architecture of the brain reflects three major evolutionary epochs, corresponding to the dominant vertebrate […]
Introduction to Axotomy: Definition and Significance Axotomy is a precise neurobiological term referring to the surgical or traumatic severing of an axon, the long, slender projection of a nerve cell, or neuron, that typically conducts electrical impulses away from the neuron’s cell body. This procedure results in immediate denervation of the target tissue, fundamentally altering […]
Introduction and Definitional Duality of Center The term center, within the realm of psychology and neurophysiology, carries a profound definitional duality, encompassing both a specific physical location responsible for control and an abstract psychological state denoting optimal integration and balance. In its most concrete application, particularly in neurophysiology, a center is defined as a specialized […]
The Fundamental Concept of Antidromic Conduction The concept of antidromic conduction stands as a critical, though specialized, topic within neurophysiology, describing a highly specific mode of action potential propagation that runs contrary to the natural, established physiological direction of nerve impulse travel. Normally, under standard conditions within the central and peripheral nervous systems, the nerve […]
Introduction and Definition of Extinction The term extinction, while commonly understood in biology to denote the irreversible loss of a species or genus, holds a highly specific and critical definition within the field of psychology, particularly behavioral science. In the context of learning theory, extinction refers to the procedure through which a previously learned behavioral […]
Defining the Phenomenon of Phase Locking Phase locking represents a fundamental and critical physiological mechanism observed within the nervous system, particularly pronounced in the auditory pathway, describing the propensity for a neuron, specifically an auditory nerve fiber, to generate an action potential at a precise and consistent temporal relationship relative to the phase of an […]
Introduction to the Concept of Refractoriness The term refractory is employed across medicine, pathology, and neurophysiology to describe a fundamental state of unresponsiveness or resistance. In its broadest application, it signifies an inability to react to a stimulus or treatment that would typically elicit a positive response. This concept is crucial for understanding the limitations […]
Defining the Positive Afterpotential The Positive Afterpotential (PAP), also referred to in some contexts as the after-depolarization or the period following the hyperpolarizing undershoot, represents a crucial phase in the recovery cycle of an excitable cell, typically a neuron or a muscle fiber, immediately following the conclusion of an action potential spike. It is characterized […]
Premotor Theory of Attention The Core Definition of the Premotor Theory The Premotor Theory of Attention (PTA) posits a profound and fundamental connection between the cognitive process of selecting information—what we call attention—and the systems responsible for preparing and executing physical movements. In its simplest form, the theory argues that shifting spatial attention is not […]
Dale’s Principle in Neurobiology Introduction and Core Definition Dale’s Principle, often referred to incorrectly as Dale’s Law, is a fundamental hypothesis in the field of neuroscience concerning the biochemical function of nerve cells. At its core, the principle asserts that a mature neuron releases the same primary chemical messenger—the same neurotransmitter—at all of its synaptic […]
Movement Chaining in Psychology and Neuroscience Core Definition of Movement Chaining Movement chaining is a foundational concept in the study of motor control, positing that complex, sequential motor actions are executed through a series of discrete, linked steps, where the successful completion of one step serves as the essential stimulus or cue for the initiation […]
Motor Evoked Potential The Core Definition of Motor Evoked Potential The Motor Evoked Potential (MEP) is fundamentally an electrophysiological signal generated in response to direct electrical or magnetic stimulation of the brain’s motor pathways, typically the motor cortex, and subsequently recorded from the peripheral muscles. It represents the functional integrity of the entire central motor […]
Tonotopic Organization Introduction and Core Definition Tonotopic organization is a fundamental and highly conserved principle governing the structure and function of the Auditory System, describing the spatial arrangement of neurons according to the frequency of sound they best respond to. Essentially, it functions as a highly precise frequency map, organized topographically across various structures of […]
Dream Stimulus: A Review of Neurophysiological Findings Abstract Dreams are a complex neurophysiological phenomenon in which mental images, emotions, and sensations are experienced during sleep. The role of external stimuli in the formation of dreams has been studied extensively, and research suggests that dream stimuli can alter dream content. This review outlines current knowledge of […]
Multiple-Spike Recording: A Review Introduction Multiple-spike recording is a technique for recording the electrical activity of neurons over a period of time. It is used to investigate the temporal relationship between neuronal firing and the behavior of an organism. This article reviews the history and current applications of multiple-spike recording, as well as the challenges […]
Event-Related Magnetic Field (ERF) Introduction to Event-Related Magnetic Fields (ERFs) An Event-Related Magnetic Field (ERF) represents a specialized neurophysiological technique employed to precisely measure the brain’s magnetic activity in direct response to a specific internal or external stimulus or event. This method provides an invaluable window into the dynamic workings of the human brain, allowing […]