Developmental Disorders, Learning, and Memory. Critical improvements and milestones in the research in the field of biopsychology, seeking to establish ways through which the brain and nervous functions influence human behavior. Developments that have been made are far-reaching, demonstrating the importance of understanding whether defects in the brain and nervous systems could the reason behind some development disorders, their impact on working memory and learning. To narrow down the complex issue of biopsychology, two development disorders have been selected, hyperactivity disorder (ADHD) and dyslexia, which are assessed to establish how they are related to the brain and nervous system. Scholarly articles that have extensively covered select development disorders are reviewed, and research design developed.
Developmental Disorders, Learning, and Memory
According to Moreau and Waldie (2016), development learning disorders affect children, impairing their experience of learning in the classroom. Dyslexia and attention-deficit/hyperactivity disorder (ADHD) are two learning disorders that are evaluated by Moreau and Waldie (2016), where they claim they cannot be linked to the inadequate learning environment or the intellectual ability of the children but rather to the underlying brain function. Maturation of the prefrontal areas enables and support executive function such as reading and cognitive processes. In the early stages, neural activity may be disorganized and inefficient which eventually transit to a better efficient system but when the transition phase is defective, it leads to ADHD and dyslexia. Further, variation in the cerebral lateralization related to language processing and executive functions is another mechanism responsible for dyslexia and ADHD, which influences learning and working memory (Moreau & Waldie, 2016).
Applying a data-driven, and transdiagnostic approach, Holmes et al. (2020) assessed cognitive dimensions to the children aged 5-18 years that had been identified to have problems in attention, learning and working memory. It was established that learning-related problems and working memory was stronger and higher for the students with ADHD which are linked to defective executive function, controlled by the frontal lobes of the brain (Holmes et al, 2020). Ethical approval was granted to the researchers, and guardians were involved in providing written informed consent while verbal assent was obtained from the children. Therefore, Holmes et al. (2020) provide rich information demonstrating the influence of the brain and nervous system on human behaviors such as reading and learning.
In another study which entailed meta-analysis of voxel-based morphometry studies, it was established that the differences in the gray matter overlap are associated with dyslexia and ADHD, and particularly reduced gray matter in the right caudate which may be relevant to shared cognitive correlates in the executive functioning (McGrath & Stoodley, 2019). Gray matter in the brain is instrumental in information processing, where the neuropsychological level of analysis reveals that aspects of executive functioning which include working memory and deficit in the processing speeds are the risk factors for dyslexia and ADHD (McGrath & Stoodley, 2019). Technology advancement has been pivotal in biopsychology, noted by the fact data was visualized using MRIcroGL with ALE maps as an overlay and the MNI152 brain as the underlay (McGrath & Stoodley, 2019). Therefore, dyslexia and ADHD are not normal learning and memory difficulties but are neurodevelopmental disorders.
Ogundele (2018) outlines social, emotional and behavioral problems, which are experienced by children with developmental disorders such as ADHD and dyslexia responding to the question of behavioral and social influence of said disorders. Challenging behaviors exhibited by those suffering from developmental and mental health disorders, disruptive behavior patterns, etiology and risk factors to children behavioral disorders are also explored as well as management and treatment approaches that can be adopted by pediatricians, widening understanding of development disorders (Ogundele, 2018). Reduced gray matter volume in the amygdala, frontal cortex, temporal lobes, and the anterior insula is linked to the neurodevelopment disorders such as dyslexia and ADHD.
In further exploration to establish a connection between developmental disorders and brain functions through the framework of neuro-auditory systems, presenting adequate evidence on how different regions of the brain causes dyslexic and ADHD. Various regions of the brain such as the subcortical, prefrontal and parietal areas are connected to the auditory cortex, with sensorimotor synchronization affecting attentive behaviors (Serrallach et al, 2016). It noted that children diagnosed with ADHD do have altered brain recruitment for attention networks, and neural inefficiency contributes to ADHD and dyslexia disorders, which demonstrates that brain and nervous systems influence human behaviors such as learning and working memory, and are linked to developmental learning disorders. In the study, 147 children were the neuro-auditory profiles designed by means of structural MRI, MEG, and psychoacoustics tests (Serrallach et al, 2016). To meet ethical concerns, research was approved Medical Faculty of an institution while parents provided informed consent in the written and children informed assent (Serrallach et al, 2016). This shows that desired ethical principles in the research were observed.
Dyslexia origin is traced to the physical location in the brain, which denotes that developmental of dyslexia relates to the brain function. Less gray matter in the left parietotemporal area, and less white matter in the same area, are a notable feature on the brain that are associated with dyslexia (Hudson, High & Otaiba, 2007). Functional magnetic resonance imaging (fMRI), the method used for imaging brain function, shows a failure of the left hemisphere rear brain systems to function properly during reading (Hudson, High & Otaiba, 2007). The study by Munzer, Hussai and Soares (2020), digs deeper into neurobiology widening understanding of developmental learning disorders such as dyslexia are connected to the brain. Taking a closer look at the neural organization provides an understanding of neurological disorders. The left inferior frontal region, the dorsal temporoparietal region, and the ventral occipitotemporal region form the significant components of the left hemisphere of the brain, which is crucial for reading. Cognitive impairments based on the region that is affected, abnormal functioning of the hub region that connects information between different systems and RSNs, and global reduction in the neuroplasticity of the brain, are potential causes of dyslexia. Therefore, studies that have been reviewed demonstrate that the brain and nervous systems are the origins of dyslexia and ADHD.
In the reviewed literature, the bulk of the research has been on illustrating causes of ADHD and dyslexia, parts of the brain that are impaired and neural disorganization that lead to two neurodevelopmental disorders. However, the question that has not to be addressed is how failure in the identified brain parts and nervous systems influence human behavior. Therefore, from this research gap, a research question has been identified which is,” How ADHD and dyslexia disorders are linked to the brain and nervous system and, and how do they influence human behavior?”
Meta-analysis research design would be adopted, where results from previous research would be assessed which have used modern technologies such as fMRI, MRI, MEG system to study how brain function, and identify defective parts for those with ADHD and dyslexia. Additionally, social function, human activities and behaviors that cut across cognitive dimension, interpersonal relationships and learning behaviors would be identified which could have been adversely affected when areas of the brain and nervous systems cause ADHD and dyslexia. This will help to address a very important question on how ADHD and dyslexia influence human behavior.
Finally, since this research depends on previous research, it means that no human subjects would be included in the research. Instead, previous research from which information would be obtained and consolidated to conclude must have met ethical concerns. Notable ethical principles that previous research must meet include: approval from necessary review board where human subjects are used, informed consent from participants that are above 18 years, parent provide informed consent and subjects informed assent when subjects are lower than 18 years, and protection of subjects from harm. The sources that have been used in the literature review have been assessed and found to meet outlined ethical principles. Therefore, ethical concerns have been adequately addressed.
Holmes, J., Guy, J., Kievit, R. A., Bryant, A., Mareva, S., & Gathercole, S. E. (2020). Cognitive dimensions of learning in children with problems in attention, learning, and memory. Journal of Educational Psychology. https://psycnet.apa.org/fulltext/2020-85078-001.pdf
Hudson, R. F., High, L., & Otaiba, S. A. (2007). Dyslexia and the brain: What does current research tell us?. The reading teacher, 60(6), 506-515. https://www.readingrockets.org/article/dyslexia-and-brain-what-does-current-research-tell-us
McGrath, L. M., & Stoodley, C. J. (2019). Are there shared neural correlates between dyslexia and ADHD? A meta-analysis of voxel-based morphometry studies. Journal of neurodevelopmental disorders, 11(1), 1-20. https://jneurodevdisorders.biomedcentral.com/articles/10.1186/s11689-019-9287-8
Moreau, D., and Waldie, K. E. (2016). Developmental Learning Disorders: From Generic Interventions to Individualized Remediation. Frontiers in psychology, 6, 2053. https://doi.org/10.3389/fpsyg.2015.02053
Munzer, T., Hussain, K., & Soares, N. (2020). Dyslexia: neurobiology, clinical features, evaluation and management. Translational pediatrics, 9(Suppl 1), S36. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7082242/
Ogundele M. O. (2018). Behavioral and emotional disorders in childhood: A brief overview for paediatricians. World journal of clinical pediatrics, 7(1), 9–26. https://doi.org/10.5409/wjcp.v7.i1.9
Serrallach, B., Groß, C., Bernhofs, V., Engelmann, D., Benner, J., Gündert, N., … & Seither-Preisler, A. (2016). Neural biomarkers for dyslexia, ADHD, and ADD in the auditory cortex of children. Frontiers in neuroscience, 10, 324.https://www.frontiersin.org/articles/10.3389/fnins.2016.00324/full