Functional Brain Imaging Summary

Imagine a football player is tackled and hits the back of his head. As a result, his brain has hit the back of the cranium, then the front.

Due to this, it has been deemed difficult to determine which deficit is the consequence of which part of a lesion. To overcome this problem, other methods are being used to aid in the visualisation of memory processes in the healthy parts of the brain. These come in the form of functional neuroimaging studies using Positron Emission Tomography (PET) and Functional Magnetic Resonance Imaging (fMRI). These studies have allowed researchers to target specific memory processes using targeted psychological experiments. However, with all psychological experiments, there are limitations to using neuroimaging equipment. PET and fMRI attain their signals from local changes in blood flow or metabolism correlated with neural activity rather than from brain waves (or signals). The local vascular changes affect the distribution of an injected radionuclide (e.g. O15) in PET or magnetic properties that are blood-oxygen level dependent (BOLD) in fMRI. The indirect measure of neural activity limits the temporal and spatial fidelity of activations.

Ischaemic stroke is a serious neurological condition in which a blood clot stops blood flow to the brain and for which immediate action is required. It is the fourth cause of death in Western society, causing 87% of all strokes, and also results in long-term disability among survivors (Bunevicius et al., 2013). In the United States, about 800,000 strokes occur each year, and approximately six million Americans are living with neurological deficits caused by ischaemic strokes (Duong, 2012). Therefore, neuroradiological imaging has become a major section in radiology departments.

Heyman states, “In a most impressive display of brain technology, scientists have used scanning technologies to observe metabolic activity of the brain in action. In a typical

Plummeting the load of dishonesty has been the crucial goal of the cohort for ages to melt off the hassle of suspicion and increase the competency of human beings. The multitude of all ages has tried their best to wipe out deception and regain trust with the available technologies. Still the fundamental nature of humanity to deceive can’t be altered. Recently, fMRI imaging has come forth as a Protector of the mental capacity to assess deception and discriminate dishonesty from actuality. The future of the courtroom seems endangered with the over persuasiveness of this neuroscience data. How does fMRI work? Functional magnetic resonance imaging (fMRI): is a technique that directly evaluates the blood flow to the brain, thereby providing information

Medical imaging, how interesting is that, it’s a tool that helps go into depth about how the brain is functioning, and how it has developed. Medical imaging has many great and useful resources. Imagine how great it will be if medical imaging would develop even more than we have it today, we can find many new ways of discovering---BEYOND what we have already discovered. According to Kunio Doi in his article titled, “Diagnostic Imaging over the Last 50 years: Research and Development in the Medical Imaging Science and Technology,” indicates “In the last 50 years imaging has grown to a high state of high level;” as a matter of fact technology we have today can become an even more successful resource in a matter of years. Mary Lou Jepsen in her

Neuroimaging is a tool employed by neuroscientists who look to analyze specific regions of activity. Often, delineating these regions of activity is difficult: brain anatomies vary from person to

MRP can provide a valuable tool in initial diagnosis as well as staging of different brain diseases and pathologies. Following that, MRP can also aid in differentiate between the true and pseudo progression, differentiate between high and low grade Glioma, differentiate between infectious and neoplastic focal brain lesion, and detect the efficacy of anti-angiogenic cancer therapy, identifying the real tumor margin as well as guiding stereotactic

In this essay I will be discussing how the reporter used fMRI imaging techniques to measure the brain activity while playing violent M- rated video games. Their theory was that violent video games can produce violent tendencies in people that play M-rated games. In contrast, I feel as if the reporters didn’t go into detail about the control groups and how they were detected whether they were desensitized to emotions. I personally believe that violent video games cause violent tendencies because you are what you do repeatedly. These men spend at least two hours daily playing these violent games like Grand Theft Auto, Call of Duty and other extreme games. What is that really teaching them?

First, the standard DWI measurement shows the average molecule displacements among each imaging voxel without differentiating the diffusion from different tissue sub-compartment within the voxel. Furthermore, DWI cannot show enough tissue geometric information because, to avoid T2 signal overlay the DWI signal, DWI does not take advantage of T2 information during the signal acquisition. Finally, conventional DWI images are subject to significant distortion from magnetic field inhomogeneities.

Apparent diffusion coefficient (ADC) value, which is dependent on the material being imaged, then can be determined to show the amount of water movement. Because molecules diffuse in three dimensions, diffusion weighted images can be obtained along the X, Y, and Z planes. These images then can be averaged to produce a more accurate measurement. In each of the three planes, two strong dephasing and rephasing gradient pulses are added to a standard MRI pulse sequence at varying degrees of strength. The bright areas show the volume of the brain that may be damaged. Strong magnetic field gradients are used to separate fast and slow moving water molecules. The strength and duration of these gradient pulses are much stronger than those used with standard imaging sequences. The degree of diffusion weighting depends on the region of interest as well as the time between the diffusion gradients.

Keywords: Positron emission tomography, single photon emission computed tomography, magnetic resonance imaging, ultrasound, bioluminescent, fluorescence

The pathological changes of the carotid artery can affect the brain and on another hand the hemodynamic changes at the heart, aorta and brain can be detected at carotid artery. For example, if the narrowing of the carotid arteries becomes severe enough to block blood flow, or a piece of atherosclerotic plaque breaks off and obstructs blood flow to the brain, a stroke may develop. Therefore, this is a strong rationale to consider that cardiovascular event may ultimately be more closely related to carotid artery rather than brachial artery [5]. Carotid arteries, the major vessels supplying the brain are directly connected to aorta closer than peripheral arteries such as brachial and radial artery (Figure 1). Currently research is more focused on non-invasive determination of pressure waveform measured at carotid artery [12].

Diffusion-tensor (DT) imaging allows measurement of the random motion of water molecules and provides information about cellular integrity and pathology. In a highly ordered white matter tract, water molecules diffuse faster in the direction parallel to the tract than in the perpendicular direction, thats because the transverse diffusion is restricted by axonal membranes and myelin sheaths [21]. In contrast to isotropic diffusion where diffusion is equal in all directions, diffusion with a strong directional preference is called anisotropic diffusion [8]. DT imaging is useful for identification and estimation of neural tracts integrity at the subcortical level [7]. Also, the new technique of DT tractography allows the visualization of the integrity of the corticospinal tract (CST), which is the major neuronal pathway that controls voluntary movements and is the most important motor pathway for predicting motor outcome in the human brain [22].

The neurons in the brain tissue communicate with each other via electrical signals, generating measurable action potential activity. Electrophysiological techniques have been developed to measure this electrical activity. Electrophysiological techniques are some of the classic methods of brain research, partly because they are very sensitive and accurate. They provide quite a number of insights into the subject’s mind as well as allow for study of how the brain works. They can be used during brain surgery as well as when the patient is awake and conscious, as the brain itself does not sense pain during the measurements. Although electrophysiology has been around for close to half a century, it has attained appreciable advances only in the last two decades. These advances have revolutionized the study of brain structure and functions, allowing neurophysiologists to monitor the brain’s activities directly during experiments (Sutler et al., 1999). Even with its significant impact in neurology, however, its presence has been so commonplace that many people no longer realize its ubiquity. This essay explores three electrophysiological techniques namely patch clamp, sharp electrodes, and brain slice recording. It describes how each of these techniques works as well as how advances in the techniques have