advanced biology

Advanced Biology

basic biology

Basic Biology

chemistry

Chemistry

clinical skills

Clinical Skills

engineering

Engineering

environmental sciences

Environmental Sciences

physics

Physics

psychology

Psychology

jove science education

JoVE Science Education

A video library dedicated to teaching the practice and theory of scientific experiments through engaging and easy-to-understand visual demonstrations.

Education

An Introduction to Neurophysiology

Neurophysiology is broadly defined as the study of nervous system function. In this field, scientists investigate the central and peripheral nervous systems at the level of whole organs, cellular networks, single cells, or even subcellular compartments. A unifying feature of this wide-ranging discipline is an interest in the mechanisms that lead to the generation and propagation of electrical impulses within and between neurons. This subject is important not only for our understanding of the fascinating processes driving human thought, but also for our ability to diagnose and treat disorders related to nervous system malfunction. This video will provide an introduction to the field of neurophysiology, beginning with a brief history of neurophysiological research that showcases landmark studies like Galvani&#8217;s observations of twitching frog legs and Eccles&#8217;s discovery of the chemical synapse. Next, key questions asked by neurophysiologists are introduced, followed by an overview of some prominent experimental tools used to answer those questions. The methods presented range from techniques used to investigate single cells, like patch clamping, to those that can measure activity across large regions of the brain, like electroencephalography (EEG). Finally, applications of neurophysiological research are discussed, including the development of brain-machine interfaces that allow for device control using thought.

Introduction to Neurophysiology: Methods &amp; Applications

 Neurophysiology is broadly defined as the study of nervous system function. In this field, scientists investigate the central and peripheral nervous ...

Patch Clamp Electrophysiology

Neuron cell membranes are populated with ion channels that control the movement of charge into and out of the cell, thereby regulating neuron firing. One extremely useful technique for investigating the biophysical properties of these channels is called patch clamp recording. In this method, neuroscientists place a polished glass micropipette against a cell and apply suction to form a high resistance seal. This process isolates a small &#8220;patch&#8221; of membrane that contains one or more ion channels. Using an electrode within the micropipette, researchers can &#8220;clamp&#8221; or control the electrical properties of the membrane, which is important for analysis of channel activity. The electrode also allows for changes in the voltage across the membrane, or the flow of ions through the membrane, to be recorded. This video begins with an overview of the principles behind patch clamp electrophysiology, an introduction to the necessary equipment, and descriptions of the various patch configurations, including whole cell, cell-attached, perforated, inside-out, and outside-out patches. Next, the key steps of a typical whole-cell patch clamp experiment are outlined, in which a current-voltage (IV) curve is generated. Finally, applications of patch clamp recording are provided to demonstrate how the biophysical properties of ion channels, cell excitability, and neuroactive compounds are evaluated in neurophysiology labs today.

Patch Clamp Electrophysiology: Principle &amp; Applications

Neuron cell membranes are populated with ion channels that control the movement of charge into and out of the cell, thereby regulating neuron firing. One ...

Calcium Imaging in Neurons

Calcium ions play an integral role in neuron function: They act as intracellular signals that can elicit responses such as altered gene expression and neurotransmitter release from synaptic vesicles. Within the cell, calcium concentration is highly dynamic due to the presence of pumps that selectively transport these ions in response to a variety of signals. Calcium imaging takes advantage of intracellular calcium flux to directly visualize calcium signaling in living neurons.This video begins with an overview of the key reagents used for this technique, known as calcium indicator dyes. The discussion includes an introduction to the commonly used dye Fura-2 and some basic principles behind how both ratiometric and non-ratiometric calcium indicators work. Next, a typical calcium imaging experiment is presented, from preparing the cells and dye to capturing and analyzing the fluorescent images. Finally, several experimental applications of calcium imaging are provided, such as the study of neuronal network activity and sensory processing.

Calcium Imaging in Neurons Using Fura-2

Calcium ions play an integral role in neuron function: They act as intracellular signals that can elicit responses such as altered gene expression and ...

An Introduction to Neuroanatomy

Neuroanatomy is the study of nervous system structures and how they relate to function. One focus of neuroanatomists is the macroscopic structures within the central and peripheral nervous systems, like the cortical folds on the surface of the brain. However, scientists in this field are also interested in the microscopic relationships between neurons and glia - the two major cell types of the nervous system. This video provides a brief overview of the history of neuroanatomical research, which dates back to the 4th century BC, when philosophers first proposed that the soul resides in the brain rather than the heart. Key questions asked by neuroanatomists are also reviewed, including topics like the role cytoarchitecture, or the arrangement of neurons and glia, plays in brain function; and how neuroanatomy changes as a result of experience or disease. Next, some of the tools available to answer these questions, such as histology and magnetic resonance imaging, are described. Finally, the video provides several applications of neuroanatomical research, demonstrating how the field lives on in today&#8217;s neuroscience labs.

Neuroanatomy and Cytoarchitecture

Neuroanatomy is the study of nervous system structures and how they relate to function. One focus of neuroanatomists is the macroscopic structures within ...

Rodent Stereotaxic Surgery

Stereotaxic (or stereotactic) surgery is a method used to manipulate the brain of living animals. This technique allows researchers to accurately target deep structures within the brain through the use of a stereotaxic atlas, which provides the 3D coordinates of each area with respect to anatomical landmarks on the skull. After the skull is exposed, anesthetized animals are mounted on a specialized instrument known as a stereotaxic frame, which enables the precise placement of experimental tools at the defined coordinates. Stereotaxic surgery is a versatile approach that can be used to generate lesions, manipulate gene expression, or deliver experimental agents to the brain.This video-article provides a general overview of the principles behind stereotaxic surgery, including instructions for using a stereotaxic atlas and the stereotaxic frame, and an introduction to reading the Vernier scale for measurement of probe movements. The subsequent discussion outlines the steps required to perform the surgical procedure. Lastly, a broad range of technical applications are presented, such as the insertion of electrical probes to measure brain activity and genetic manipulation of brain tissue.

Stereotaxic (or stereotactic) surgery is a method used to manipulate the brain of living animals. This technique allows researchers to accurately target ...

Histological Staining of Neural Tissue

In order to examine the cellular, structural and molecular layout of tissues and organs, researchers use a method known as histological staining. In this technique, a tissue of interest is preserved using chemical fixatives and sectioned, or cut into very thin slices. A variety of staining techniques are then applied to provide contrast to the visually uniform sections. In the study of neuroanatomy, histological techniques are frequently applied to visualize and study nervous system tissue. This video focuses on histological staining techniques for neural tissue. An overview of common brain stains is provided, including those that specifically mark neuronal cell bodies, like Nissl stains, and those that selectively highlight myelinated axons, like the Luxol Fast blue stain. Immunohistological techniques, which take advantage of the specific interaction between antibodies and unique cellular proteins, are also discussed. Next, the preparation of brain samples for staining is described, including the basic steps for fixation, embedding, sectioning, and rehydration of the tissue. The presentation also provides a step-by-step procedure for immunohistological staining followed by a Nissl stain, in addition to practical applications of these techniques.

Brain Stains: Histological Staining of Neural Tissue

In order to examine the cellular, structural and molecular layout of tissues and organs, researchers use a method known as histological staining. In this ...

An Introduction to Behavioral Neuroscience

Behavioral neuroscience is the study of how the nervous system guides behavior, and how the various functional areas and networks within the brain correlate to specific behaviors and disease states. Researchers in this field utilize a wide variety of experimental methods ranging from complex animal training techniques to sophisticated imaging experiments in human subjects. This video first offers a historical overview of some of the major milestones that lead to our current understanding of the brain&#8217;s control over behavior. Then, some of the fundamental questions asked by behavioral neuroscientists are presented, which all involve the study of neural correlates, or specific brain regions whose activation is responsible for a given function. Next, prominent methods used to answer those questions are reviewed for both human and animal subjects, such as operant conditioning and functional neuroimaging. Finally, experimental applications of these techniques are presented, including animal training using a Skinner box, and the use of electroencephalography to investigate human neurological disease.

Behavioral Neuroscience; Learning and Cognitive Processes

Behavioral neuroscience is the study of how the nervous system guides behavior, and how the various functional areas and networks within the brain ...

The Morris Water Maze

The Morris water maze is one of the most widely used behavioral tests for studying spatial learning and memory. In the initial phases of this task, rodents must swim to a platform to escape from a pool of water. The platform is then hidden under the water&#8217;s surface, so that the animal is required to remember it&#8217;s location in order to escape.This simple yet powerful maze design can be used to assay cognitive function, study animal models of neurodegenerative disease, and test potential drug therapies.
This video provides an introduction to the Morris water maze and the principles surrounding its use, including a discussion of the different types of memory tested in the maze, important points to consider when designing and conducting this experiment, and the procedures for setup and running of the test. Several applications of the maze are examined, such as investigating how radiation treatment may lead to memory impairment. Finally, other types of water mazes, such as the 8-arm radial maze, are introduced to show how this paradigm can be adapted to engage different types of memory.

The Morris water maze is one of the most widely used behavioral tests for studying spatial learning and memory. In the initial phases of this task, ...

fMRI: Functional Magnetic Resonance Imaging

Functional magnetic resonance imaging (fMRI) is a non-invasive neuroimaging technique used to investigate human brain function and cognition in both healthy individuals and populations with abnormal brain states. Functional MRI utilizes a magnetic resonance signal to detect changes in blood flow that are coupled to neuronal activation when a specific task is performed. This is possible because hemoglobin within the blood has different magnetic properties depending on whether or not it is bound to oxygen. When a certain task is performed, there is an influx of oxygenated blood to brain regions responsible for that function, and this influx can then be detected with specific MRI scan&#160;parameters. This phenomenon is termed the blood oxygen level ependent (BOLD) effect, and can be used to create maps of brain activity.
This video begins with a brief overview of how MRI and fMRI signal is obtained. Then, basic experimental design is reviewed, which involves first setting up a stimulus presentation that is specifically designed to test the function that will be mapped. Next, key steps involved in performing the fMRI scan are introduced, including subject safety and setting up at the scanner. Commonly used steps for data processing are then presented, including pre-processing and statistical analysis with the general linear model. Finally, some specific applications of fMRI are reviewed, such as investigations into abnormal function in psychological disorders, and combining fMRI with complimentary imaging modalities, such as diffusion tensor imaging (DTI).

Functional magnetic resonance imaging (fMRI) is a non-invasive neuroimaging technique used to investigate human brain function and cognition in both ...

An Introduction to Cellular and Molecular Neuroscience

Cellular and molecular neuroscience is one of the newest and fastest growing subdisciplines in neuroscience. By investigating the influences of genes, signaling molecules, and cellular morphology, researchers in this field uncover crucial insights into normal brain development and function, as well as the root causes of many pathological conditions.
This video introduction to the fascinating world of cellular and molecular neuroscience begins with a timeline of landmark studies, from the discovery of DNA in 1953 to more recent breakthroughs like the cloning of ion channels. Next, key questions in the field are introduced, such as how genes influence neuron activity and how the nervous system is modified by experience. This is followed by brief descriptions of some prominent methods used to analyze genetic material in neurons, manipulate expression of genes, and visualize neurons and their parts. Finally, several applications of molecular and cellular neuroscience are presented to demonstrate how cellular and molecular approaches can be used to profile neuron populations and explore their functions.

Cellular and Molecular Neuroscience Research

Cellular and molecular neuroscience is one of the newest and fastest growing subdisciplines in neuroscience. By investigating the influences of genes, ...

Primary Neuronal Cultures

The complexity of the brain often requires neuroscientists to use a simpler system for experimental manipulations and observations. One powerful approach is to generate a primary culture by dissecting nervous system tissue, dissociating it into single cells, and growing those cells in vitro. Primary cultures make neurons and glia easily accessible to the experimental tools required for techniques like genetic manipulation and time-lapse imaging. Furthermore, these cultures represent a highly controllable environment in which to study complex phenomena such as cell-cell interactions.
This video provides an overview of the major steps in producing primary neuronal cultures, which include selecting and dissecting the tissue of interest, mechanically and chemically breaking down the tissue to produce a single cell suspension, plating the cells, and maintaining the cultures in the appropriate media. Several example experiments are also presented to show how cultured cells can be used to investigate protein trafficking, morphological changes, and electrophysiology in living neurons.

Primary Neuronal Cultures and Electrophysiology

The complexity of the brain often requires neuroscientists to use a simpler system for experimental manipulations and observations. One powerful approach ...

Neuronal Transfection Methods

Transfection - the process of transferring genetic material into cells - is a powerful tool for the rapid and efficient manipulation of gene expression in cells. Because this method can be used to silence the expression of specific proteins or to drive the expression of foreign or modified proteins, transfection is an extremely useful tool in the study of the cellular and molecular processes that govern neuron function. However, mature neurons have a number of properties that make them difficult to transfect, so specialized techniques are required for the genetic manipulation of this cell type. 	This video reviews the principles and rationale behind transfecting neurons. Three common strategies for neuronal transfection are discussed, including nucleofection, gene-gun, and viral transduction. In addition to describing how each of these techniques overcomes the challenges associated with transfecting neurons, the presentation includes a description of how all three methods are performed. Finally, several applications of neuronal transfection are introduced, such as the expression of fluorescent tubulin proteins to visualize neuron morphology, and selective gene silencing to generate a cell culture model of Parkinson&#8217;s disease.

Neuronal Transfection and Nucleofection Methods

Transfection - the process of transferring genetic material into cells - is a powerful tool for the rapid and efficient manipulation of gene expression in ...

Explant Culture of Neural Tissue

The intricate structure of the vertebrate nervous system arises from a complex series of events involving cell differentiation, cell migration, and changes in cell morphology. Studying these processes is essential to our understanding of nervous system function as well as our ability to diagnose and treat disorders that result from abnormal development. However, neural tissues are relatively inaccessible for experimental manipulations, especially in embryonic mammals. As a result, many scientists take advantage of explant culture in order to study neurodevelopmental processes in an &#8220;organotypic&#8221; environment, meaning that the tissue is removed from the organism but its complex cellular architecture is maintained. Generally, explant cultures are created by careful dissection of neural tissue that is then submerged in carefully designed growth media and cultured in vitro.
This video will first provide a brief overview of neural explant culture, including its advantages over other in vitro methods and important considerations for maintaining healthy tissue. Next, a general protocol will be provided for setting up an explant culture from embryonic mouse brain, outlining the isolation of embryos from the mother and dissection of the brain. The presentation also includes an overview of slice culture, in which thin sections of nervous system tissue are generated for improved visual access to the developing cells. Lastly, a few applications of these techniques will be provided to demonstrate how they can be used to answer important questions in the neurodevelopmental field.

The intricate structure of the vertebrate nervous system arises from a complex series of events involving cell differentiation, cell migration, and ...

Murine In Utero Electroporation

In utero electroporation is an important technique for studying the molecular mechanisms that guide the proliferation, differentiation, migration, and maturation of cells during neural development. Electroporation enables the rapid and targeted delivery of material into cells by utilizing electrical pulses to create transient pores in cell membranes. Although electroporation has traditionally been used in in vitro studies, scientific advancements have now broadened its utilization to intact organs, such as those found in mouse embryos developing in utero. This video will introduce the key principles behind in utero electroporation in addition to reviewing the basic surgical techniques required to access developing embryos within a pregnant rodent. Details of the injection and electroporation steps are provided along with important considerations for directing gene delivery to specific brain regions. Finally, neurobiological applications of in utero electroporation are presented, such as investigating how specific genes contribute to neural development and how connections form between developing neurons.

Murine In Utero Electroporation

In utero electroporation is an important technique for studying the molecular mechanisms that guide the proliferation, differentiation, migration, and ...

An Introduction to Developmental Neurobiology

Developmental neuroscience is a field that explores how the nervous system is formed, from early embryonic stages through adulthood. Although it is known that neural progenitor cells follow predictable stages of proliferation, differentiation, migration, and maturation, the mechanisms controlling the progression through each stage are incompletely understood. Studying development is not only important for understanding how complex structures are assembled, but also for characterizing and treating developmental disorders. Since injury repair processes are similar to those that occur in development, this field is also a promising source of insight into when and how nervous system tissues regenerate.This video provides a brief overview of the field of developmental neuroscience, including some key experiments that have advanced our understanding of the mechanisms controlling the formation of early neural tissue and the further specialization of those cells into discrete subsets of neurons. The discussion focuses on prominent questions that developmental biologists are asking and then demonstrates some of the methods that they use to investigate these questions. Finally, applications of the techniques are presented to provide insight into what it means to be a developmental neuroscientist today. The range of experiments demonstrated includes genetic manipulation of intact embryonic brains, targeted differentiation of stem cells into nervous system cells, and staining techniques that allow for the quantification of specific developmental events, like the formation of new connections between neurons.

Developmental Neurobiology: Concepts and Techniques

Developmental neuroscience is a field that explores how the nervous system is formed, from early embryonic stages through adulthood. Although it is known ...

Science Education - Advanced Biology

Neuroscience