CK120 Psychology : Functional Magnetic Resonance Imaging

Answer:

Functional magnetic resonance imaging (FMRI) is an advanced neuroimaging mechanism using MRI techniques that analyzes and measures brain activity depending on the blood flow. This technique mainly focuses its basic idea on the information that neural activities are connected to the cerebral places. When a part of the brain is in use, blood flow to that place increases.

This essay focuses on the characteristics of physiological, psychological and main functioning of the brain by use of an FMRI system. The characteristics so defined will lead to a large-scale use of FMRI in many sectors.

This essay further focuses on the aspects of human sleep in early childhood. The main neurological signals that are measured by the FMRI systems are used to determine the psycho physiological aspects of human behavior.

The FMRI uses blood oxygen level dependent (BOLD) concept, which is used to scan the brain or body depending on the change in blood flow. From the early ages, FMRI has been used because it replaces the need of human surgery or ingestion of chemicals to provide experiments (Clark et al., 2012). FMRI is used in both research work and clinical work. It can also be applied with existing technologies to make it even better like the EEG. Some companies have already made its applications like the lie detectors. However, it has not been proved yet about the efficiency of the device but still it provides a concept (Le Bihan, 2012).

Human behavior refers to the array of emotions and physical actions associated with an individual or people. However, specific aspects of one’s personality remains constant through their lives, many traits change with time as the individual progress their way from childhood to adulthood. The behavior of individuals lies between common, unusual, acceptable or highly unacceptable. Human behavior is experienced throughout a person’s lifetime. This behavior is affected by various factors like genetics, social life, faith and attitude (Seligman & Csikszentmihalyi, 2014).

Average sleep is needed throughout childhood. There is difference in every child and every child has different sleep patterns. Experts believe that there is wide variation in sleep patterns in children but the needs for sleep are especially shown in the first age of birth (Henderson et al., 2012). Most children between 2 to 5 years go to sleep between 7 to 9 pm and wakes up at around 6.30 to 8 am. Many children start to let go of their napping schedules during daytime, but a report shows that 15% of children usually sleeps once during the day (Maski & Kothare, 2013).

FMRI is built on the early concepts of MRI technologies and discovery of the properties of blood rich in oxygen. The tube of an MRI scanner is cylindrical in shape and houses a powerful magnet. A typical magnet in a research facility has a magnetic strength of 3 Teslas. The resulting magnetic field affects the atomic nuclei and aligns them in the direction of the field. The degree of alignment depends on the strength of the magnet (Clark et al., 2012). When pointing in equal directions, tiny magnetic signals from individual nuclei adds up coherently, this results in a large enough signal to measure. Signal from hydrogen nuclei in water is measured in case of FMRI. The key for effective measurement is that the signal varies in structure with respect to surroundings. This process is mainly used in case of grey matter, white matter or other cerebral space. The neurons receive oxygen through the hemoglobin in red blood cells. When neural activities increase, blood flow also increases. Oxygenated hemoglobin is diamagnetic while de-oxygenated hemoglobin is paramagnetic. This difference in magnetic characteristics causes changes differences in the signals and thus provides the basis for measurement of capillary activities (Power, Schlaggar & Petersen, 2014).

Many experiments conducted for early childhood sleep lacks the complete spatial responses that are available in FMRI analysis. A novel experiment was conducted to know the brain functioning of early childhood sleep from FMRI analysis (Becker, 2013). In the experiment, stimulus- dependent as well as stimulus independent reactions were noted. Thirteen children were showed auditory signals (vocal or non-vocal) to study their responses whereas twelve children were showed 2.5 Hz flashlights. Direct comparisons in the auditory responses showed the activation of bilateral superior temporal gyri/sulci and right cerebellum. However, studies for direct response from non-vocal signals were greater than the vocal ones whose effect was shown in many cerebral regions including superior temporal gyri/sulci, medial frontal cortex and right lateral cerebellum. The occipital cortex showed the localization of the visual stimuli. In addition, the stimulus independent responses from the FMRI showed functional connectivity between the STG and other temporal regions. The functional connectivity was also fed from the occipital and parietal cortex. Thus, a 2-4 year old children showed differential FMRI response in both visual and auditory analysis. In addition, functional connectivity was shown in superior temporal regions along with several other cerebral regions (Lei et al., 2012).

There is no storage of glucose in the brain. When the ions are activated, bringing them back to their original state of polarization requires pumping of blood across the cerebral membranes. The energy required is provided by synthesis of glucose (Becker, 2013). More blood is pumped in to bring the required glucose to the brain. The amount of glucose brought in far exceeds the amount consumed in breaking the glucose, which results in reduction of de-oxygenated blood. This causes change in the magnetization property. The blood flow corresponds to different consumption levels of glucose in different regions like amygdala or the thalamus (Sheldon et al., 2014). In the parietal or frontal lobes, consumption is more than incoming flow. This causes changes in sensitivity in measurement. The hemoglobin differs in response to magnetism by the presence of a bound oxygen molecule. Attraction of the molecule is more, which results in distortion of the surrounding magnetic field made by the MRI scanner. The physiological characteristics determine the temporal sensitivity and the time resolution (TR) which determines the time required for a portion of the cerebra to get excited (Matricciani et al., 2012)

An important aspect of neurological brain imaging research is to show the varieties of brain connectivity in different regions. Functional connectivity of the brain refers to the undirected associations whereas effective connectivity shows directed relationships (Sheldon et al., 2014). A psychological interaction measures the activities as specified by the physiological variables without denoting the direction of influences. This process helps to determine the level of interactions between experimental variables (attention levels) and signal coupling from a particular area of the brain (source) and voxel signals from the rest of the brain. A psycho physiological interaction refers to the changes of one area of the brain to the area in context to the psychological interactions. This means that a regional response from a particular region for an experimental factor is modulated from distal cerebral regions. A research study conducted to a group of schizophrenic and healthy people were showed facial tests during screening. The analysis of FMRI responses showed that in cases of schizophrenic patients, perceptions were reduced in the right amygdala for fear perception as compared to the healthy ones (Becker, 2013).

The cerebral activities differ for all reactions. When a person is sleeping or when he/she is awake, several regions of the brain shows different mapping of the signals ranging from simple works like taking a cup or complex activities like learning a language. Thus, FMRI technique is used to study the mapping signals from the brain, which is non-invasive and safe. It is already being used in many research works and studies. Thus, it can be concluded that the use of FMRI for studying natural sleep in 2-4 years children might prove to be a valuable tool for research work.

References:

Becker, S. P. (2013). Topical review: Sluggish cognitive tempo: Research findings and relevance for pediatric psychology. Journal of Pediatric Psychology, 38(10), 1051-1057.

Clark, V. P., Coffman, B. A., Mayer, A. R., Weisend, M. P., Lane, T. D., Calhoun, V. D., ... & Wassermann, E. M. (2012). TDCS guided using fMRI significantly accelerates learning to identify concealed objects. Neuroimage, 59(1), 117-128.

Henderson, L. M., Weighall, A. R., Brown, H., & Gareth Gaskell, M. (2012). Consolidation of vocabulary is associated with sleep in children. Developmental science, 15(5), 674-687.

Le Bihan, D. (2012). Diffusion, confusion and functional MRI. Neuroimage, 62(2), 1131-1136.

Lei, D., Ma, J., Du, X., Shen, G., Tian, M., & Li, G. (2012). Spontaneous brain activity changes in children with primary monosymptomatic nocturnal enuresis: A resting?state fMRI study. Neurourology and urodynamics, 31(1), 99-104.

Maski, K. P., & Kothare, S. V. (2013). Sleep deprivation and neurobehavioral functioning in children. International Journal of Psychophysiology, 89(2), 259-264.

Matricciani, L. A., Olds, T. S., Blunden, S., Rigney, G., & Williams, M. T. (2012). Never enough sleep: a brief history of sleep recommendations for children. Pediatrics, 129(3), 548-556.

Power, J. D., Schlaggar, B. L., & Petersen, S. E. (2014). Studying brain organization via spontaneous fMRI signal. Neuron, 84(4), 681-696.

Seligman, M. E., & Csikszentmihalyi, M. (2014). Positive psychology: An introduction. In Flow and the foundations of positive psychology (pp. 279-298). Springer Netherlands.

Sheldon, S. H., Kryger, M. H., Ferber, R., & Gozal, D. (2014). Principles and Practice of Pediatric Sleep Medicine E-Book. Elsevier Health Sciences.