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Functional neuroimaging is the use of neuroimaging technology to measure an aspect of brain function, often with a view to understanding the relationship between activity in certain brain areas and specific mental functions. It is primarily used as a research tool in cognitive neuroscience and neuropsychology. Neuroimaging includes the use of various techniques to either directly or indirectly image the structure, function, or pharmacologyof the brain. ...
Comparative brain sizes In animals, the brain, or encephalon (Greek for in the head), is the control center of the central nervous system. ...
The field of Cognitive neuroscience concerns the study of the neural mechanisms underlying cognition and is a branch of biological psychology which, in turn, is part of the wider field of neuroscience, the most comprehensive interdisciplinary discipline studying the brain . ...
Neuropsychology is a branch of psychology that aims to understand how the structure and function of the brain relate to specific psychological processes. ...
Common methods include Positron Emission Tomography (PET), Functional Magnetic Resonance Imaging (fMRI), multichannel Electroencephalography (EEG) or Magnetoencephalography (MEG), and Near Infrared Spectroscopic Imaging (NIRSI). PET, fMRI and NIRSI can measure localized changes in cerebral blood flow related to neural activity. These changes are referred to as "activations". Regions of the brain which are activated when a subject performs a particular task may play a role in the neural computations which contribute to the behaviour. For instance, widespread activation of the occipital lobe is typically seen in tasks which involve visual stimulation (compared with tasks that do not). This part of the brain receives signals from the retina and is believed to play a role in visual perception. Sample fMRI data This example of fMRI data shows regions of activation including primary visual cortex (V1, BA17), extrastriate visual cortex and lateral geniculate body in a comparison between a task involving a complex moving visual stimulus and rest condition (viewing a black screen). ...
Sample fMRI data This example of fMRI data shows regions of activation including primary visual cortex (V1, BA17), extrastriate visual cortex and lateral geniculate body in a comparison between a task involving a complex moving visual stimulus and rest condition (viewing a black screen). ...
Image of a typical positron emission tomography (PET) facility Positron emission tomography (PET) is a nuclear medicine medical imaging technique which produces a three dimensional image or map of functional processes in the body. ...
Functional magnetic resonance imaging (fMRI) is the use of MRI to measure the haemodynamic response related to neural activity in the brain or spinal cord of humans or other animals. ...
Electroencephalography is the neurophysiologic measurement of the electrical activity of the brain by recording from electrodes placed on the scalp or, in special cases, on the cortex. ...
Magnetoencephalography (MEG) is the measurement of the magnetic fields produced by electrical activity in the brain, usually conducted externally, using extremely sensitive devices such as SQUIDs. ...
Computational neuroscience is an interdisciplinary field which draws on neuroscience, computer science and applied mathematics. ...
The occipital lobe is the visual processing center of the mammalian brain. ...
Vision can refer to: Visual perception is one of the senses. ...
Human eye cross-sectional view. ...
Visual perception is one of the senses, consisting of the ability to detect light and interpret (see) it as the perception known as eyesight, sight or naked eye vision. ...
The measure used in a particular study is generally related to the particular question being addressed. Measurement limitations vary amongst the tecnniques. For instance, MEG and EEG record the magnetic or electrical fluctuations that occur when a population of neurons is active. These methods are excellent for measuring the time-course of neural events (on the order of miliseconds,) but generally bad at measuring where those events happen. PET and fMRI measure changes in the composition of blood near a neural event. Because measurable blood changes are slow (on the order of seconds,) these methods are much worse at measuring the time-course of neural events, but are generally better at measuring the location.
Traditional "activation studies" focus on determining distributed patterns of brain activity associated with specific tasks. However, we are able to more thoroughly understand brain function by studying the interaction of distinct brain regions, as a great deal of neural processing is performed by an integrated network of several regions of the brain. An active area of neuroimaging research involves examining the functional connectivity of spatially remote brain regions. Functional connectivity analyses allow the characterization of interregional neural interactions during particular cognitive or motor tasks or merely from spontaneous activity during rest. fMRI and PET enable us to create functional connectivity maps of distinct spatial distributions of temporally correlated brain regions called functional networks.
A direct method to measure functional connectivity is to observe how stimulation of one part of the brain will affect other areas. This can be done noninvasively in humans by combining Transcranial magnetic stimulation with one of the neuroimaging tools such as PET, fMRI, or EEG . Massimini et al. (Science, Sept. 30, 2005) used EEG to record how activity spreads from the stimulated site. They reported that in non-REM sleep (REM = Rapid eye movement), although the brain responds vigorously to stimulation, functional connectivity is much attenuated from its level during wakefulness. Thus, during deep sleep, "brain areas do not talk to each other". Transcranial magnetic stimulation (TMS) is the use of powerful rapidly changing magnetic fields to induce electric fields in the brain by electromagnetic induction without the need for surgery or external electrodes. ...
Rapid eye movement (REM) is the stage of sleep during which the most vivid (though not all) dreams occur. ...
Functional neuroimaging studies have to be carefully designed and interpreted with care. Statistical analysis (often using a technique called statistical parametric mapping) is often needed so that the different sources of activation within the brain can be distinguished from one another. This can be particularly challenging when considering processes which are difficult to conceptualise or have no easily definable task associated with them (for example belief and consciousness). Statistical parametric mapping or SPM is a statistical technique for examining differences in brain activity recorded during functional neuroimaging experiments using neuroimaging technologies such as fMRI or PET. It may also refer to a specific piece of software created by the Wellcome Department of Imaging Neuroscience (part of University College...
Wiktionary has related dictionary definitions, such as: belief Belief is usually defined as a conviction to the truth of a proposition. ...
Consciousness is a quality of the mind generally regarded to comprise qualities such as subjectivity, self-awareness, sentience, sapience, and the ability to perceive the relationship between oneself and ones environment. ...
Functional neuroimaging draws on data from many areas other than cognitive neuroscience, including biological sciences (such as neuroanatomy and neurophysiology) and fields such as physics and maths, to further develop and refine the technology. The field of Cognitive neuroscience concerns the study of the neural mechanisms underlying cognition and is a branch of biological psychology which, in turn, is part of the wider field of neuroscience, the most comprehensive interdisciplinary discipline studying the brain . ...
Neuroanatomy is the anatomy of the nervous system. ...
Neurophysiology is a part of physiology as a science, which is concerned with the study of the nervous system. ...
Physics is the science of Nature. ...
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