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<p>Clinical psychophysiology (also known as applied psychophysiology) aims to correlate the objective data with the subjective report, for example, linking EEG with behavior.&nbsp;Whereas the scientist-physician will link the EEG to neurological pathologies,
    the neurotherapist will link the EEG to psychopathology and sometimes to physical pathology.&nbsp; The neurotherapist uses psychophysiological measures, such as<b> EEG</b> and <b>quantitative EEG</b>, to assess the client, and later treats the client
    with applied psychophysiology (i.e. neurofeedback, neurotherapy, and biofeedback), while the neurologist looks at the neurophysiology for assessment purposes, alone, typically prescribing pharmaceuticals or surgery as treatment.&nbsp;&nbsp;</p>Neuroscientific
technology has exploded in the past 20 years, however, and the fields of applied psychophysiology, experimental psychology, and medical neuroscience are three separate fields&nbsp;that are accessing the tremendous advancements in viewing the brain and
its activity. Today, there is a proliferation of scientific psychological research involving brain imaging technology. The <b>MRI (magnetic resonance imaging)</b>—a 3D view of the brain from various cuts—has led to the <b>fMRI (functional magnetic resonance imaging)</b>,
which reveals every region’s activity and how much those parts of the brain are being used. <b>Diffusion tensor imaging (DTI)</b> has evolved to diffusion tensor magnetic resonance imaging tractography, which allows us to see and understand connections
in the brain. And <b>Positron Emission Tomography (PET)</b> scans have revolutionized our capability of viewing the activity of the brain by showing metabolic and vascular activity in real time.<br><p><br></p><p>The poor signal to noise ratio and expense of MEG make this technology impractical for most imaging situations. qEEG provides a much better signal to noise ratio and is far cheaper and easier to use. PET scans and SPECT scans require radioactive injections and SPECT scans have less spatial resolution than fMRI. The most popular imaging method for medical clinical imaging today is fMRI. At this point in time qEEG, using sLORETA analysis methods, has close to the same spatial resolution and superior temporal resolution with respect to MRI. It is also far cheaper and easier to use. The main drawback is its inability to image subcortical structures, however new methods of cortical analysis are being developed to make it possible to assess subcortical function based on cortical dynamics (Yehudit Meir-Hasson et al., 2013).</p><h5><b style="color: rgb(55, 71, 79); font-family: &quot;Open Sans&quot;; font-size: 1.715rem;"><b>Quantitative EEG</b>&nbsp;(qEEG)</b></h5>
<p><b>Quantitative EEG</b>&nbsp;uses fast fourier transform (FFT) and other algorithms to decompose EEG data into subsets of frequencies (integers) and connectivity measures. Sometimes these measures are displayed relative to a "normative database" of individuals
    who are healthy for their age (in these cases, the clinician can compare their patient's EEG to see how deviant it is from the same-aged "norm"). Other quantitative databases simply quantify EEG data, but do not compare the data to a norm in order
    to indicate standard deviations from the normal same-aged demographic. EEG and qEEG can only provide data from cortical sources of brainwaves. It cannot directly measure subcortical structures and activity. EEG is the sum of dipoles representing pyramidal
    cells oriented perpendicular to the surface of the scalp.&nbsp;</p>
<p><b>Below are two separate images from QEEGs</b></p>
<p><img src="@@PLUGINFILE@@/raw%20vs.%20QEEG.png" alt="raw vs. QEEG" width="700" height="422" class="img-responsive atto_image_button_left"><br></p>
<p><span><b style="font-weight: bold;"><img src="@@PLUGINFILE@@/QEEG.png" alt="QEEG" width="500" height="330" class="img-responsive atto_image_button_right"><br></b></span></p>
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<p><br></p><p></p><h3><b style="font-size: 1rem;">Magnetoencephalography (MEG) (see image below) i</b><span style="font-size: 1rem;">s a technique for mapping brain activity by recording magnetic fields produced by electrical currents occurring naturally in the brain, using arrays of SQUIDs (superconducting quantum interference devices).</span></h3><span style="font-size: 1rem;"><img src="@@PLUGINFILE@@/MEG%20%282%29.jpg" alt="MEG" width="300" height="452" class="img-responsive atto_image_button_left">Applications of MEG include localizing regions affected by pathology before surgical removal, determining the function of various parts of the brain, and neurofeedback. MEG</span><span style="font-size: 1rem;">&nbsp;is
    the sum of magnetic fields from dipoles of neurons parallel to the surface of the scalp located in the sulci of the cortex and is consequently complementary to EEG analysis. One measures perpendicular sources of electromagnetic activity and the other
    measures tangential sources of magnetic activity.</span><br><p></p>
<p><img src="@@PLUGINFILE@@/MeG.png" alt="MEG2" width="600" height="335" class="atto_image_button_middle"><br></p><p><b style="font-size: 1rem;"><b>Magnetic Resonance Imaging (MRI) (see image below)</b>&nbsp;</b><span style="font-size: 1rem;">uses a strong magnetic field to align the protons of hydrogen atoms in the water of the body, it generates a radio wave pulse that knocks them out of alignment and then measures the radio waves that the protons emit as they realign. Protons in different tissues realign at different rates or "relaxation times" and can be used to construct images of the tissue.&nbsp;</span><br></p><p><img src="@@PLUGINFILE@@/MRI%20Images.jfif" alt="MRI Images" width="600" height="336" class="img-responsive atto_image_button_left"><br></p><p><b><img src="@@PLUGINFILE@@/MRI2.jfif" alt="MRI2" width="500" height="333" class="atto_image_button_middle"><br></b></p><p><b style="font-size: 1rem;">Functional Magnetic Resonance Imaging (fMRI)</b><span style="font-size: 1rem;">&nbsp;uses this same technology but applies it to cerebral blood flow. It monitors changes in magnetization between oxygen rich and oxygen depleted blood which is then color coded graphically. When neurons become active, the oxygen rich blood increases within two seconds and reaches a peak in about 4 seconds. To generate 3D density distribution patterns, special mathematical image reconstruction methods are used.</span><br></p><p><img src="@@PLUGINFILE@@/fMRI%20%282%29.jfif" alt="fMRI" width="700" height="284" class="atto_image_button_middle"></p><p><span style="font-size: 1rem;">When a brain area is more active it consumes more oxygen and to meet this increased demand blood flow increases to the active area. FMRI can be used to produce activation maps showing which parts of the brain are involved in a particular mental process.</span></p><p>Oxygen is delivered to neurons by haemoglobin in capillary red blood cells. When neuronal activity increases there is an increased demand for oxygen and the local response is an increase in blood flow to regions of increased neural activity.</p><p>Haemoglobin is diamagnetic when oxygenated but paramagnetic when deoxygenated. This difference in magnetic properties leads to small differences in the MR signal of blood depending on the degree of oxygenation. Since blood oxygenation varies according to the levels of neural activity these differences can be used to detect brain activity. This form of MRI is known as blood oxygenation level dependent (BOLD) imaging.</p><p>One point to note is the direction of oxygenation change with increased activity. You might expect blood oxygenation to decrease with activation, but the reality is a little more complex. There is a momentary decrease in blood oxygenation immediately after neural activity increases, known as the “initial dip” in the haemodynamic response. This is followed by a period where the blood flow increases, not just to a level where oxygen demand is met, but overcompensating for the increased demand. This means the blood oxygenation actually increases following neural activation. The blood flow peaks after around 6 seconds and then falls back to baseline, often accompanied by a “post-stimulus undershoot”.<br></p>
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<iframe width="560" height="315" src="https://www.youtube.com/embed/rJjHjnzmvDI" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen=""></iframe>
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<p></p><p></p><img src="@@PLUGINFILE@@/PET%20scan.jpg" alt="PET Scan" width="1000" height="386" class="img-responsive atto_image_button_middle"><b>Positron Emission Tomography (PET)</b>&nbsp;scans are dependent on the injection of radioactive isotopes into the blood. Regions that use more blood as they are activated emit positrons that can be measured by special sensors placed around the head. The
    resolution is not as good as MRI.<p></p>
<p><b>Single photon emission computed tomography (SPECT, or less commonly, SPET)</b>&nbsp;is a nuclear medicine tomographic imaging technique using gamma rays. It is very similar to conventional nuclear medicine planar imaging using a gamma camera. However,
    it is able to provide true 3D information. This information is typically presented as cross-sectional slices through the patient, but can be freely reformatted or manipulated as required.<img src="@@PLUGINFILE@@/SPECT.jpg" alt="SPECT Scan" width="800" height="450" class="img-responsive atto_image_button_middle"></p>
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<p>The basic technique requires injection of a gamma-emitting radioisotope into the bloodstream of the patient. Occasionally the radioisotope is a simple soluble dissolved ion, such as a radioisotope of gallium(III), which happens to also have chemical properties
    which allow it to be concentrated in ways of medical interest for disease detection. However, most of the time in SPECT, a marker radioisotope, which is of interest only for its radioactive properties, has been attached to a special radioligand, which
    is of interest for its chemical binding properties to certain types of tissues. This marriage allows the combination of ligand and radioisotope to be carried and bound to a place of interest in the body, which then allows the ligand concentration
    to be seen by a gamma-camera because the properties of radioligand bind it to certain types of tissues.&nbsp;A gamma camera captures the emissions from several different angles which can be used to generate a 3D image of the tissue that the radioligand
    binds with.</p><p><b style="font-size: 1rem;"><img src="@@PLUGINFILE@@/SPECT%20scans.jpg" alt="SPECT Scan 2" width="500" height="335" class="img-responsive atto_image_button_right"></b></p><h3><b style="font-size: 1rem;">SPECT in Functional Brain Imaging</b></h3><p></p>

<p>Because blood flow in the brain is tightly coupled to local brain metabolism and energy use, an isotope is used to assess brain metabolism regionally, in an attempt to diagnose and differentiate the different causal pathologies of dementia. In meta analysis,
    SPECT was superior to clinical exam and clinical criteria in being able to differentiate Alzheimer's disease from vascular dementias. This latter ability relates to SPECT's imaging of local metabolism of the brain, in which the patchy loss of cortical
    metabolism seen in multiple strokes differs clearly from the more even or "smooth" loss of non-occipital cortical brain function typical of Alzheimer's disease.</p>

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