Sebastian Seung: I am my connectome. Diffusion MRI image of the brain. VS Ramachandran on your mind. VS Ramachandran: The neurons that shaped civilization. Susan Savage-Rumbaugh on apes. Oliver Sacks: What hallucination reveals about our minds. Charles Limb: Your brain on improv. Christopher deCharms looks inside the brain. Functional magnetic resonance imaging. Researcher checking fMRI images Functional magnetic resonance imaging or functional MRI (fMRI) is a functional neuroimaging procedure using MRI technology that measures brain activity by detecting associated changes in blood flow. This technique relies on the fact that cerebral blood flow and neuronal activation are coupled.
When an area of the brain is in use, blood flow to that region also increases. The primary form of fMRI uses the Blood-oxygen-level dependent (BOLD) contrast, discovered by Seiji Ogawa. The procedure is similar to MRI but uses the change in magnetization between oxygen-rich and oxygen-poor blood as its basic measure. This measure is frequently corrupted by noise from various sources and hence statistical procedures are used to extract the underlying signal.
FMRI is used both in the research world, and to a lesser extent, in the clinical world. Overview History Diffusion MRI. Diffusion MRI (or dMRI) is a magnetic resonance imaging (MRI) method which came into existence in the mid-1980s. It allows the mapping of the diffusion process of molecules, mainly water, in biological tissues, in vivo and non-invasively.
Molecular diffusion in tissues is not free, but reflects interactions with many obstacles, such as macromolecules, fibers, membranes, etc. Water molecule diffusion patterns can therefore reveal microscopic details about tissue architecture, either normal or in a diseased state. The first diffusion MRI images of the normal and diseased brain were made public in 1985. Since then, diffusion MRI, also referred to as diffusion tensor imaging or DTI (see section below) has been extraordinarily successful. Its main clinical application has been in the study and treatment of neurological disorders, especially for the management of patients with acute stroke. Tan Le: A headset that reads your brainwaves. Electroencephalography. Simultaneous video and EEG recording of two guitarists improvising.
Electroencephalography (EEG) is the recording of electrical activity along the scalp. EEG measures voltage fluctuations resulting from ionic current flows within the neurons of the brain. In clinical contexts, EEG refers to the recording of the brain's spontaneous electrical activity over a short period of time, usually 20–40 minutes, as recorded from multiple electrodes placed on the scalp.
Diagnostic applications generally focus on the spectral content of EEG, that is, the type of neural oscillations that can be observed in EEG signals. EEG is most often used to diagnose epilepsy, which causes obvious abnormalities in EEG readings. It is also used to diagnose sleep disorders, coma, encephalopathies, and brain death. History Hans Berger. Henry Markram builds a brain in a supercomputer.
Kwabena Boahen on a computer that works like the brain. Gero Miesenboeck reengineers a brain. Jeff Hawkins on how brain science will change computing. Dan Dennett on our consciousness. Michael Merzenich on re-wiring the brain. Pawan Sinha on how brains learn to see. Beau Lotto: Optical illusions show how we see. Jeff Hawkins. Episodes - Brain Science Podcast. Neuron. All neurons are electrically excitable, maintaining voltage gradients across their membranes by means of metabolically driven ion pumps, which combine with ion channels embedded in the membrane to generate intracellular-versus-extracellular concentration differences of ions such as sodium, potassium, chloride, and calcium.
Changes in the cross-membrane voltage can alter the function of voltage-dependent ion channels. If the voltage changes by a large enough amount, an all-or-none electrochemical pulse called an action potential is generated, which travels rapidly along the cell's axon, and activates synaptic connections with other cells when it arrives. Neurons do not undergo cell division. In most cases, neurons are generated by special types of stem cells. A type of glial cell, called astrocytes (named for being somewhat star-shaped), have also been observed to turn into neurons by virtue of the stem cell characteristic pluripotency. Overview Anatomy and histology Neuron viewed with an electron microscope. Neuron's cobweb-like cytoskeleton (its interior scaffolding) Brain from top to bottom.
Weighing about 3 pounds (1.4 kilograms), the brain consists of three main structures: the cerebrum, the cerebellum and the brainstem. Cerebrum - divided into two hemispheres (left and right), each consists of four lobes (frontal, parietal, occipital and temporal). The outer layer of the brain is known as the cerebral cortex or the ‘grey matter’. It covers the nuclei deep within the cerebral hemisphere e.g. the basal ganglia; the structure called the thalamus, and the ‘white matter’, which consists mostly of myelinated axons. – closely packed neuron cell bodies form the grey matter of the brain. Cerebellum – responsible for psychomotor function, the cerebellum co-ordinates sensory input from the inner ear and the muscles to provide accurate control of position and movement.
Dick Swaab Wij zijn ons brein - UitgeverijContact. Hersenletsel achtergronden en aanpak / druk 1, H.J. Eilander.
Medical imageing. Kasper's neurology neighbours.