This essay will discuss the different strengths and weaknesses of different neuroimaging techniques that cognitive neuroscientists use to understand different mental processes and different biological bases of behavior. These examples include fMRI (functional magnetic resonance imaging), PET (positron emission tomography), MEG (magnetoencephalography), and TMS (transcranial magnetic stimulation). Say no to plagiarism. Get a tailor-made essay on “Why Violent Video Games Should Not Be Banned”? Get the original essay MRI is a hemodynamic method that measures the amount of deoxygenated blood in certain parts of the brain (Ward, 2016). The amount of deoxygenated blood emits a BOLD (Blood-Oxygen-Level Dependent) signal and converts into voxels (in the form of pixels) which allow us to see a 3D image of the brain and track neuronal activity (Martin & Carlson, 2019). When the amount of neuronal activity increases, the amount of blood flow also increases, leading to increased glucose levels in the brain. In turn, this causes blood vessels to dilate; obviously increasing the volume of deoxygenated blood (Heeger & Ress, 2002). One of the strengths of this technique is that it is non-invasive, meaning we don't have to insert anything into the body or brain to track this neural activity. Additionally, fMRI scans have good spatial resolution: meaning that the precision with which we can see where a certain event occurs is good (Pinel & Barnes, 2017). It can even reach up to 1 millimeter of spatial resolution if the fMRI analysis is very high resolution, however the typical BOLD response will have around 3 to 6 millimeters of spatial resolution (XUE et al., 2010). Despite the positives of fMRI, however, it also has disadvantages, such as poor temporal resolution, which implies that the time required to take a single image of the brain is slow (Cabeza & Nyberg, 2000). Martin and Carlson (2019) stated that it takes approximately 3 seconds to complete an image of the brain, which is slower than other techniques, such as an MEG scan. In addition to having poor temporal resolution, fMRI scans show correlation rather than causation, because other physiological activities in the body can cause deoxygenated blood to flow to a certain area of ​​the brain; so it is difficult to tell whether the BOLD signal is measuring what it intends to measure. Overall, fMRI is a safe, non-invasive way to measure the brain's neuronal activity with astonishing spatial resolution. Despite the low temporal resolution, fMRI is a popular method of measuring neuronal activity in the brain due to its lack of invasiveness (XUE et al., 2010). Another hemodynamic analysis technique is PET. However, unlike fMRI, PET directly measures changes in blood flow, unlike bold signals that measure deoxyhemoglobin (Ward, 2016). PET scans work by inserting a radioactive tracer into the body – this is usually a form of glucose. For example, F-18-2-fluro-2-deoxyglucose (FDG) which travels to the brain to release positron. Positrons collide with electrons in the brain, releasing gamma rays 180° apart and the activity levels of the areas are indicated by the different concentrations (Martin & Carlson, 2019). For example, a higher level of FDG absorption is found in locations that might be affected by different infections (e.g. autoimmune disease) and therefore FDG concentrations will be higher in these areas. One ofStrengths of this technique is that it has good spatial resolution – around 5 to 6 millimeters. However, a major limitation of this scanning technique is that it is invasive because it requires the injection of a tracer into the bloodstream (Martin & Carlson, 2019). . In addition, the temporal resolution is poor since it is approximately 30 seconds (Cabeza & Nyberg, 2000). Additionally, due to the levels of radioactivity and the invasive nature of this technique, children are not allowed to have these types of scans, which therefore means that we cannot see how the brain develops throughout life. childhood with this technique and limits our knowledge in this area (Martin and Carlson, 2019). In conclusion, PET is an invasive technique that hampers our knowledge of brain development during early childhood. However, despite this, PET scans have astonishing spatial resolution and have helped us understand other mental processes such as speech perception, memory and reading (Martin & Carlson, 2019). A different technique from fMRI and PET is TMS which is an electromagnetic technique which, rather than recording neuronal activity in the brain, stimulates it (Ward, 2016). TMS works by placing a magnetic coil next to the head and inside the magnetic coil there is a changing electric current which creates an electromagnetic field (Kobayashi & Pascual-Leone, 2003; Pashut et al., 2011 ). The magnetic field of the coil causes neurons inside the brain to depolarize (more likely to fire an action potential) or hyperpolarize (less likely to fire an action potential) (Kobayashi and Pascual-Leone, 2003 ). A great advantage of this technique is that it is one of the only ways to measure causality rather than correlation (Walsh & Cowey, 2000). This means that, unlike fMRI or PET, the magnetic coil next to the skull directly affects neuronal activity, which then induces a change in behavior, for example hand movement (Pashut et al. , 2011). Like fMRI, it is a non-invasive technique because it is not necessary to inject a tracer into the body (Hallett, 2007; Kobayashi & Pascual-Leone, 2003). A limitation of this technique is that if the magnetic coil temperature increases, it could potentially harm the patient and/or damage the machine (Wassermann, 1998). However, this problem could be solved by the production of a water-cooled coil which could prevent this problem from occurring (Wassermann, 1998). Although single-pulse TMS is relatively safe, repeated-pulse techniques could induce seizures in patients with previous seizures (Sack and Linden, 2003; Ward, 2016). Patients who have been diagnosed with epilepsy (or who have a family history of epilepsy) are not allowed to use TMS due to the risk of causing a possible seizure. Additionally, patients should be informed before undergoing TMS that it may cause some discomfort, as it may cause involuntary contractions of facial muscles, giving them the right to withdraw at any time if discomfort becomes too extreme (Ward, 2016). In summary, TMS has dangers, but if participants are informed beforehand and do not have a history of epilepsy, this technique is effective because it establishes a direct cause and is used to treat several disorders such as depression and anxiety (Walsh & Cowey, 2000). The final scanning technique in this trial is MEG which measures the electrical activity of the brain with a superconducting quantum interference device (SQUID) (Martin & Carlson, 2019). The SQUID device must beimmersed in liquid helium, but they are sensors placed on the patient's head to measure the magnetic activity of neurons inside the brain. Once the SQUID is placed on the skull, the head must be scanned with small magnetic coils to ensure that the person's skull is relative to the SQUID device (Proudfoot et al., 2014). A major advantage of this technique is that it constitutes a good localization technique, because when neuronal activity is stimulated in a certain area by a specific stimulus, SQUID detects the magnetic field and then shows the area that was used (Martin & Martin, 2003). ). In addition, MEG is a non-invasive technique since it only measures the magnetic field of the electrical activity of neurons; therefore not requiring the insertion of a tracer. However during an MEG scan, if there is head movement, this immediately reduces the quality of the data and therefore the patient must remain extremely still during the scan (Boto et al., 2018). Additionally, MEGs are extremely expensive and, because they must be installed behind a magnetically protected room, they are extremely difficult to move (Stam, 2010). Overall, MEGs are a non-invasive test with an amazing localization technique and are safe for participants to use, unlike TMS which has the danger of causing epileptic seizures. However, because the SQUID must be immersed in liquid helium and the technique must take place in a magnetically protected room, MEG is an expensive technique and it is impossible to move it. Keep in mind: this is just a sample. Get a personalized article now from our expert writers. Get a personalized essay In summary, all neuroimaging techniques have their strengths and weaknesses; for example, fMRI, MEG, and TMS are all non-invasive techniques while PET scans are invasive because they require the injection of a tracer that enters the body. Hemodynamic techniques have better spatial resolution compared to their temporal resolution, while the opposite could be said for electromagnetic and magnetic techniques. PET, fMRI and MEG also allow us to see a correlation between brain activity and cognitive activity while TMS is one of the only techniques that can be used to establish clear cause and effect.ReferencesBoto , E., Holmes, N., Leggett, J., Roberts, G., Shah, V., Meyer, SS, Muñoz, LD, Mullinger, KJ, Tierney, TM, Bestmann, S., Barnes, GR, Bowtell , R. and Brookes, MJ (2018). Scaling magnetoencephalography to real-world applications with a portable system. Nature, 555(7698), 657-661. https://doi.org/10.1038/nature26147Cabeza, R. and Nyberg, L. (2000). Imaging Cognition II: an empirical review of 275 PET and fMRI studies. Journal of Cognitive Neuroscience, 12(1), 1–47. https://doi.org/10.1162/08989290051137585Eysenck, MW and Keane, MT (2020). Cognitive psychology: student manual. Taylor & Francis Group. http://ebookcentral.proquest.com/lib/edgehill/detail.action?docID=6130927 Hallett, M. (2007). Transcranial magnetic stimulation: an introduction. Neuron, 55(2), 187-199. https://doi.org/10.1016/j.neuron.2007.06.026Heeger, DJ and Ress, D. (2002). What does fMRI tell us about neuronal activity? Nature Reviews Neuroscience, 3(2), 142-151. https://doi.org/10.1038/nrn730 Kobayashi, M. and Pascual-Leone, A. (2003). Transcranial magnetic stimulation in neurology. The Lancet Neurology, 2(3), 145-156. https://doi.org/10.1016/S1474-4422(03)00321-1Martin, GN and Carlson, NR (2019). Psychology (sixth grade). Pearson. http://edgehill.summon.serialssolutions.com/2.0.0/link/0/eLvHCXMwdV3JCsIwEB1cLoIH9734A0qbpNuxiuJdkeJFkjQ5ePDkxb93prYqQo8hMCQhzPJmeQCcrd3Vn07QwrM80LFVkRQG7U5mAhEpdBc8L, 16(5), 1054-1065..1041.2010.00120