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Single Person: The unmarried man or woman.
 JoVE Medicine

A Method for Quantifying Upper Limb Performance in Daily Life Using Accelerometers

1Program in Physical Therapy, Washington University School of Medicine, 2Program in Occupational Therapy, Washington University School of Medicine, 3Department of Neurology, Washington University School of Medicine, 4Mallinckrodt Institute of Radiology, Washington University School of Medicine, 5Department of Biomedical Engineering, Washington University


JoVE 55673

 Science Education: Essentials of Experimental Psychology

The Factorial Experiment

JoVE Science Education

Source: Laboratories of Gary Lewandowski, Dave Strohmetz, and Natalie Ciarocco—Monmouth University

A factorial design is a common type of experiment where there are two or more independent variables. This video demonstrates a 2 x 2 factorial design used to explore how self-awareness and self-esteem may influence the ability to decipher nonverbal signals. This video leads students through the basics of a factorial design including, the nature of a factorial design and what distinguishes it from other designs, the benefits of factorial design, the importance and nature of interactions, main effect and interaction hypotheses, and how to conduct a factorial experiment.

 JoVE Medicine

Adapted Resistance Training Improves Strength in Eight Weeks in Individuals with Multiple Sclerosis

1Motion Analysis Laboratory, Kennedy Krieger Institute, 2Physical Medicine & Rehabilitation, Johns Hopkins University School of Medicine, 3Johns Hopkins University School of Medicine, 4Department of Neurology, Johns Hopkins University School of Medicine


JoVE 53449

 Science Education: Essentials of Sensation and Perception

Inattentional Blindness

JoVE Science Education

Source: Laboratory of Jonathan Flombaum—Johns Hopkins University

We generally think that we see things pretty well if they are close by and right in front of us. But do we? We know that visual attention is a property of the human brain that controls what parts of the visual world we process, and how effectively. Limited attention means that we can't process everything at once, it turns out, even things that might be right in front of us. In the 1960s, the renowned cognitive psychologist Ulrich Neisser began to demonstrate experimentally that people can be blind to objects that are right in front of them, literally, if attention is otherwise distracted. In the 1980s and 1990s, Arien Mack and Irvin Rock followed up on Neisser's work, developing a simple paradigm for examining how, when, and why distracted attention can make people fail to see the whole object. Their experiments, and Neisser's, did not involve people with brain damage, disease, or anything of the sort, just regular people who failed to see objects that were right in front of them. This phenomenon has been called inattentional blindness. This video will demonstrate basic procedures for investigating inattentional blindness using the methods of Mack and Rock.1

 Science Education: Essentials of Lab Animal Research

Sterile Tissue Harvest

JoVE Science Education

Source: Kay Stewart, RVT, RLATG, CMAR; Valerie A. Schroeder, RVT, RLATG. University of Notre Dame, IN

In 1959 The 3 R's were introduced by W.M.S. Russell and R.L. Burch in their book The Principles of Humane Experimental Technique. The 3 R's are replacement, reduction, and refinement of the use of animals in research.1 The use of cell lines and tissue cultures that originated from research animals is a replacement technique, as it allows for many experiments to be conducted in vitro. Harvesting tissues and organs for use in cell and tissue cultures requires aseptic technique to avoid contamination of the tissues. Sterile harvest is also necessary for protein and RNA analysis and metabolic profiling of tissues. This manuscript will discuss the process of sterile organ harvest in rats and mice.

 JoVE Medicine

Computerized Dynamic Posturography for Postural Control Assessment in Patients with Intermittent Claudication

1Discipline of Exercise and Sport Science, Faculty of Health Sciences, University of Sydney, 2Department of Sport, Health and Exercise Science, University of Hull, 3Academic Vascular Department, Hull Royal Infirmary, Hull and East Yorkshire Hospitals, 4Department of Vascular Surgery, Addenbrookes Hospital


JoVE 51077

 JoVE In-Press

The 4-vessel Sampling Approach to Integrative Studies of Human Placental Physiology In Vivo

1Department of Obstetrics, Oslo University Hospital, 2Institute of Clinical Medicine, University of Oslo, 3Norwegian Advisory Unit on Women's Health, Oslo University Hospital, 4Department of Fetal Medicine, Oslo University Hospital

Video Coming Soon

JoVE 55847

 JoVE In-Press

Improving Strength, Power, Muscle Aerobic Capacity, and Glucose Tolerance through Short-term Progressive Strength Training among Elderly People

1Åstrand Laboratory of Work Physiology, The Swedish School of Sport and Health Sciences, GIH, 2Department of Neuroscience, Karolinska Institutet, 3Department of Physiology and Pharmacology, Karolinska Institutet

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JoVE 55518

 Science Education: Essentials of Lab Animal Research

Blood Withdrawal II

JoVE Science Education

Source: Kay Stewart, RVT, RLATG, CMAR; Valerie A. Schroeder, RVT, RLATG. University of Notre Dame, IN

The collection of blood from mice and rats for analysis can be done through a variety of methods. Each method of collection has variations in the type of restraint required, the invasiveness of the procedure, and the necessity of a general anesthetic.1Historically, the use of the retro-orbital sinus cavity has been used, but not without debate. The controversy related to the potential tissue damage,or even blindness,caused by retro-orbital bleeds has led to the development of facial and submandibular vein bleeding methods in mice.Blood collection from the saphenous vein in both mice and rats is another technique that has been developed. These procedures do not require anesthesia and therefore are suitable when the use of anesthetics may confound blood results or other data.

 Science Education: Essentials of Cognitive Psychology

The Precision of Visual Working Memory with Delayed Estimation

JoVE Science Education

Source: Laboratory of Jonathan Flombaum—Johns Hopkins University

Human memory is limited. Throughout most of its history, experimental psychology has focused on investigating the discrete, quantitative limits of memory—how many individual pieces of information a person can remember. Recently, experimental psychologists have also become interested in more qualitative limits—how precisely is information stored? The concept of memory precision can be both intuitive and elusive at once. It is intuitive, for example, to think a person can remember precisely how their mother sounds, making it possible to recognize one’s mother immediately over the phone or in a crowd. But how can one quantify the precision of such a memory? Exactly how similar is the memory to the voice itself? To study the precision of memory and working memory, in particular, experimental psychologists have devised a paradigm known as delayed estimation. It has been used most often, thus far, to study the precision of visual memories, especially memory for color, and to understand how memory degrades the more one tries to remember at once. This video demonstrates standard procedures for investigating the precision of color working memory using delayed estim

 JoVE Neuroscience

Characterizing the Composition of Molecular Motors on Moving Axonal Cargo Using "Cargo Mapping" Analysis

1Department of Molecular and Experimental Medicine, Dorris Neuroscience Center, The Scripps Research Institute, 2Department of Cellular and Molecular Medicine, University of California San Diego, 3Department of Bioengineering, University of California San Diego, 4Department of Neurosciences, University of California San Diego School of Medicine


JoVE 52029

 Science Education: Essentials of Cognitive Psychology

Verbal Priming

JoVE Science Education

Source: Laboratory of Jonathan Flombaum—Johns Hopkins University

Human memory seems to work in two broad ways. Like modern computers, the human mind has explicit, or declarative, memory: ask a question, and a person gives the best answer they can. Input a query, and a computer program returns the contents of the relevant parts of its stored memory. Humans also have a second kind of memory system, one not really typical of computers, one that experimental psychologists call implicit. Implicit memory is a broad term that refers to the many ways past experiences influence present behavior. Pavlov’s famous dogs, for example, learned to associate the sound of a bell with mealtime. Eventually, they began salivating whenever they heard a bell, even if food was not delivered. Humans also possess implicit memory. Implicit memories, for example, are the reason it can be difficult to fall asleep in a new place; people associate their bedroom environment and their nighttime routines with sleepiness. Implicit memory is thought to guide human behavior in a wide array of circumstances. It is the kind of memory that guides manners and social behaviors, the kind of memory that puts relevan

 Science Education: Essentials of Neuropsychology

Decoding Auditory Imagery with Multivoxel Pattern Analysis

JoVE Science Education

Source: Laboratories of Jonas T. Kaplan and Sarah I. Gimbel—University of Southern California

Imagine the sound of a bell ringing. What is happening in the brain when we conjure up a sound like this in the "mind's ear?" There is growing evidence that the brain uses the same mechanisms for imagination that it uses for perception.1 For example, when imagining visual images, the visual cortex becomes activated, and when imagining sounds, the auditory cortex is engaged. However, to what extent are these activations of sensory cortices specific to the content of our imaginations? One technique that can help to answer this question is multivoxel pattern analysis (MPVA), in which functional brain images are analyzed using machine-learning techniques.2-3 In an MPVA experiment, we train a machine-learning algorithm to distinguish among the various patterns of activity evoked by different stimuli. For example, we might ask if imagining the sound of a bell produces different patterns of activity in auditory cortex compared with imagining the sound of a chainsaw, or the sound of a violin. If our classifier learns to tell apart the brain activity patterns produced by these three stimuli, then we can conclude that the auditory cortex is activated in a distinct

 Science Education: Essentials of Sensation and Perception

The Staircase Procedure for Finding a Perceptual Threshold

JoVE Science Education

Source: Laboratory of Jonathan Flombaum—Johns Hopkins University

Psychophysics is the name for a set of methods in perceptual psychology designed in order to relate the actual intensity of stimuli to their perceptual intensity. One important aspect of psychophysics involves the measurement of perceptual thresholds: How bright does a light need to be for a person to be able to detect it? How little pressure applied to the skin is detectable? How soft can a sound be and still be heard? Put another way, what are the smallest amounts of stimulation that humans can sense? The staircase procedure is an efficient technique for identifying a person's perceptual threshold. This video will demonstrate standard methods for applying the staircase procedure in order to identify a person's auditory threshold, that is, the minimal volume necessary for a tone to be perceived.

 Science Education: Essentials of Cognitive Psychology

Binocular Rivalry

JoVE Science Education

Source: Laboratory of Jonathan Flombaum—Johns Hopkins University

Why do people have two forward-facing eyes? By presenting the brain with two ever so slightly different images it becomes possible to comprehend visual problems that are far more difficult to process through a single eye. Chief among these is the problem of 3-D perception, seeing the world in three dimensions, despite retinal inputs in only two dimensions. What happens if each eye receives two completely different images? That does not happen in nature, to be sure, but it can be contrived in the laboratory in a set-up called binocular rivalry. Binocular rivalry is a common laboratory paradigm for investigating the ways that the brain integrates information from two eyes, and in recent years, the mechanisms responsible for producing conscious experience.

 Science Education: Essentials of Neuropsychology

Using TMS to Measure Motor Excitability During Action Observation

JoVE Science Education

Source: Laboratories of Jonas T. Kaplan and Sarah I. Gimbel—University of Southern California

Transcranial Magnetic Stimulation (TMS) is a non-invasive brain stimulation technique that involves passing current through an insulated coil placed against the scalp. A brief magnetic field is created by current in the coil, and because of the physical process of induction, this leads to a current in the nearby neural tissue. Depending on the duration, frequency, and magnitude of these magnetic pulses, the underlying neural circuitry can be affected in many different ways. Here, we demonstrate the technique of single-pulse TMS, in which one brief magnetic pulse is used to stimulate the neocortex. One observable effect of TMS is that it can produce muscle twitches when applied over the motor cortex. Due to the somatotopic organization of the motor cortex, different muscles can be targeted depending on the precise placement of the coil. The electrical signals that cause these muscle twitches, called motor evoked potentials, or MEPs, can be recorded and quantified by electrodes placed on the skin over the targeted muscle. The amplitude of MEPs can be interpreted to reflect the underlying excitability of the motor cortex; for example, when the motor cortex is activated, observed MEPs are larger.

 Science Education: Essentials of Cognitive Psychology

Dichotic Listening

JoVE Science Education

Source: Laboratory of Jonathan Flombaum—Johns Hopkins University

It is a well-known fact that the human ability to process incoming stimuli is limited. Nonetheless, the world is complicated, and there are always many things going on at once. Selective attention is the mechanism that allows humans and other animals to control which stimuli get processed and which become ignored. Think of a cocktail party: a person couldn’t possibly attend to all of the conversations taking place at once. However, everyone has the ability to selectively listen to one conversation, leading all the rest to become unattended to and nothing more than background noise. In order to study how people do this, researchers simulate a more controlled cocktail party environment by playing sounds to participants dichotically, i.e., by playing different sounds simultaneously to each ear. This is called a dichotic listening paradigm. This experiment demonstrates standard procedures for investigating selective auditory attention with a paradigm called dichotic listening.

 JoVE Cancer Research

A Syngeneic Mouse Model of Metastatic Renal Cell Carcinoma for Quantitative and Longitudinal Assessment of Preclinical Therapies

1Department of Urology, University of Minnesota, 2Masonic Cancer Center, University of Minnesota, 3Microbiology, Immunology, and Cancer Biology Graduate Program, University of Minnesota, 4Department of Medical Microbiology, Immunology and Cell Biology, Southern Illinois University School of Medicine, 5Simmons Cancer Institute


JoVE 55080

 Science Education: Essentials of Sensation and Perception

The Ames Room

JoVE Science Education

Source: Laboratory of Jonathan Flombaum—Johns Hopkins University

The most difficult challenge of visual perception is often described as one of recovering information about three-dimensional space from two-dimensional retinas. The retina is the light-sensitive tissue inside the human eye. Light is reflected from objects in the world, casting projections on the retina that stimulate these light sensitive cells. Objects that are side-by-side in the world will produce side-by-side stimulations on the retina. But objects that are more distant from the observer cannot produce more distant stimulations, compared to nearby objects that is. Distance-the third dimension-is collapsed on the retina. So how do we see in three dimensions? The answer is that the human brain applies a variety of assumptions and heuristics in order to make inferences about distances given the inputs received on the retina. In the study of perception, there is a long tradition of using visual illusions as a way to identify some of these heuristics and assumptions. If researchers know what tricks the brain is using, they should be able to trick the brain into seeing things inaccurately. This video will show you how to build an Ames Room, a visual illusion that illustrates one of the assumptions applied by the hum

 JoVE In-Press

Modified Terminal Restriction Fragment Analysis for Quantifying Telomere Length Using In-gel Hybridization

1Departments of Pathology and Infectious Diseases and Microbiology, University of Pittsburgh, 2University of Pittsburgh Cancer Institute, 3Department of Environmental and Occupational Health, University of Pittsburgh, 4Departments of Psychiatry, Psychology, Behavioral & Community Health Sciences, University of Pittsburgh

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JoVE 56001

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