Functional Magnetic Resonance Imaging (fMRI),which is one of the most exciting recent developments in biomedical magnetic resonance imaging, allows the non-invasive visualisation of human brain function(1).
Functional MRI is a measurement technique based on ultrafast MR imaging sequences that are sensitive to the physiological changes of cerebral blood flow (CBF) and cerebral blood volume (CBV).These allow the researcher to measure changes in brain function typically via increases or decreases in blood oxygenation during the scanning(2).
The detection of neural activation in fMRI relies on perturbations of the water magnetization that are associated with the hemodynamic change (3).
Advantage and Disadvantage of fMRI
One of the greater advantages of fMRI is the spatial resolution (millimeters), so we can say MR imaging has outstanding spatial resolution but has a short coming with respect to temporal resolution of less than a second (4).
EEG
Electroencephalography is a cheap non-invasive technique which has become widely used in studying brain activity to measure the electric potential differences on the scalp produced by the active cortical neurons (5).
Moreover, EEG provides a direct and real time measurement of neural activity. The temporal resolution is of the order of a few milliseconds, which allow rapid changes in cortical function to be followed. On the other hand the spatial resolution is relatively low (6, 7).
MEG
Magnetoencephalography (MEG) is a non invasive technique for studing neuronal activity in the brain. Unlike electrophysiological methods that depend on volume currents, MEG depends on the primary current (2, 8).
MEG is closely related to EEG. MEG is a more expensive method and provides be...
... middle of paper ...
...ram Recordings. Journal of Magnetic Resonance Imaging 27:607-616 (2008).
11-Karen J. Mullinger, Simultaneous EEG and fMRI at high fields. PhD Thesis 2008.
12-Matthew J. Brooks. Jiri Vrba, Karen J. Mullinger, Geroa Bjork Geirsdottir, Winston X. Yan, Claire M. Stevenson, Richard Bowtell, Petter G. Morris. Source Ilcalisation in concurrent EEG/fMRI: Application at 7T. NeuroImage 45(2009) 440-452.
13-Christos E. Vasios, Leonardo M. Angelone, Patrick L. Purdon, Jyki Ahveninen, John W. Belliveau, and Giorgio Bonmassar. EEG/(f)MRI measurements at 7 Tesla using a new EEG cap (''InkCap''). NeuroImage 33 (2006) 1082-1092.
14-Marcus A. Gray, Ludovico Minati, Neil A. Harrison, Peter J. Gianaros, Vitaly napadow, and Hugo D. Critchley. Physiological recording: Basic concepts and implemntation during functional magnetic resonance imaging. Neuroimage. 2009; 47(3-8): 1105-1115.
...son, M.A., Lainhart, J.E., Anderson, J.S. (2013) An Evaluation of the Left-Brain vs. Right-Brain Hypothesis with Resting State Functional Connectivity Magnetic Resonance Imaging. PLoS ONE 8(8). E71275, DOI:10.1371/journal.pone.0071275
Kanske, P., Heissler, J., Schönfelder, S., Forneck, J., & Wessa, M. (2013). Neural correlates of
Neuroimaging is a multidiscipline science and experts from the field of psychology, statistics, physics and physiology all contribute to its further development (Poldrack et al., 2007). In the last 20 years the imaging techniques developed from single proton emission tomography (SPET) to positron emission tomography (PET) and finally to functional magnetic resonance imaging (fMRI) (Page, 2006). Their applications are numerous in experimental and cognitive psychology. However, at one level they can constitute another dependent variable (brain activity) as a response to an independent variable (stimulus manipulation) and at the other level, understanding the structure and processes of the brain can shed light on ‘normal’ cognitive functioning (Kaye, 2010). Therefore, this essay will argue that imaging techniques not only tell us about the brain structure but also try to explain its cognitive functions. Two non-invasive imaging techniques will be put forward, namely, electroencephalogram (EEG) that measures electrical activity and gives excellent temporal resolution and fMRI that is based on changes in blood supply and provides excellent spatial resolution. The claim will be evaluated in the light of their basic assumptions, methodology and contribution to examining the brain function. Relevant evidence of studies with healthy adults will be provided. Finally, technologies that can only show the brain structure will be introduced.
In both clinical care and research, the use of brain imaging, also known as “neuroimaging”, is becoming an increasingly important technique. New technologies such as Functional Magnetic Resonance Imaging, or FMRI, allow researchers to study the brain at a level which was never thought possible. This noninvasive procedure allows researchers to visualize brain structure and function, at both the molecular and whole brain level (A.) Scientists are now able to better understand neural networks and a variety of other cognitive processes. For the first time in human history, extremely complex wonders of the brain are being uncovered. Psychiatric diseases, human emotion, personality traits, and many other phenomena that were once mysteries are now being deeply analyzed and understood. Each day new doors are being opened...
The least invasive method of BCI uses a set of electrodes attached to the scalp (Figure 3) to read brain signals however, to get a higher resolution, a chip can be inserted into the grey matter of the brain. (Grabianowski, n.d.) . The use of BCI has great implications for people with limited mobility and ghpeople who have lost limbs and has been used to control prosthetic arms. (Neurogadget,
Sullivan, S. J., Hammond-Tooke, G. D., Schneiders, A. G., Gray, A. R., & McCrory, P. (2012). The diagnostic accuracy of selected neurological tests. Journal of Clinical Neuroscience, 19. 423-427. doi:10.1016/j.jocn.2011.09.011
The diagnosis of epilepsy is usually made after the patient experiences a second unprovoked seizure (Leppik, 2002). Diagnosis is often difficult, however, since it is unlikely that the physician will actually see the patient experience and epileptic seizure, and therefore must rely heavily on patient’s history. An electroencephalography (EEG) is often used to examine the patient’s brain waves, and some forms of epilepsy can be revealed by a characteristic disturbance in electrical frequency (Bassick, 1993). The variations in frequency can take form as spikes or sharp waves (Fisher, 1995). The variations are divided into two groups, ictal electrograph abnormalities, which are disturbances resulting from seizure activity, and interictal electrograph abnormalities, or disturbances between seizures. The EEG can also give clues as to which region of the brain the disturbances arise from. Interictal temporal spikes will predict the side of seizure origin in 95% of patients if three times as ...
According to Russell Poldrack’s article, what fMRI can tell us is often overrated despite its powerful impact on the study of the human brain. fMRI is a useful technique that allows us to image brain activities by measuring blood flow in the brain. It expanded our understanding of mental disorders from a biological perspective and helped us understand structures and functions of the brain. However, there are several limitations on what neuroimaging can tell us because it is difficult to determine how our brain works or how we can diagnose and treat mental disorders from them.
...owell, E. R., Thompson, P. M., & Toga, A. W. (2004). Mapping changes in the human cortex
In persons suffering from epilepsy, the brain waves, electrical activity in the part of the brain called the cerebral cortex, have a characteristically abnormal rhythm produced by excessive electrical discharges in the nerve cells. Because these wave patterns differ markedly according to their specific source, a recording of the brain waves, known as an electroencephalogram (EEG) is important in the diagnosis and study of the disorder. Diagnosis also requires a thorough medical history describing seizure characteristics and frequency.
Since the brain is extremely fragile and difficult to access without risking further damage, imaging techniques are used frequently as a noninvasive method of visualizing the brain’s structure and activity. Today's technology provides many useful tools for studying the brain. But even with our highest technology out there we do not know everything definitely. We do have fallbacks at times and these fallbacks can lead to serious problems.
The best way for someone to see the brain activity and how it is functioning to tell future decisions, is a PET scan. A PET scan is short for positron emission tomography which shows how the brain and tissues are working. It is a radioactive substances that tracks injuries or diseases within the brain. Another scan that can be used is an MRI. An MRI is short for magnetic resonance imaging which is a scan in the head to be able to see trauma to the brain which shows as bleeding or
The technologies used by the researchers range from functional magnetic resonance imaging (fMRI) that measures the changes in the different parts of the brain, to Steady state topography (SST) an...
Brain-computer interfaces provide a wide array of possibilities for people with physical disabilities. This could change the lives of thousands, think of all the people suffering from illnesses or complications such as paralysis, locked in syndrome, stroke or severe brain trauma. B...
The biological perspective looks at how the environment and physical causes influences behavior. In the biological perspective, neuroscience plays a crucial role in explaining how the brain and the nervous system influence behaviors. Neuroscientist describes how the brain process thoughts, emotions, feelings, and how the physical body is driven by these mental processes. This branch of psychology, engages in a variety of research such as the study of genetics, brain cells, and the function of the brain across a period of time. This is done using positron emission tomography (PET). This technique is used with radio active glucose to indicate areas of activity in the brain. Another technique that is done to conduct brain research is functional magnetic resonance imaging (IMR). It uses powerful magnets and radio equipment that provides comprehensive pictures of soft tissues of the brain.