DOI: 110.5176/2251-3833_GHC19.155
Authors: Assoc. Prof. Paul A L S Hwang
Abstract: Neuroscience advances have exploded in the last 50 years since the Decade of the Brain in the USA, similar to prgrams in Canada and the European Union as well as the UK. Today’s advances range from single-unit recording of ion-cahnnels with microelectrodes, to animal models of physiological and pathological models, both KO and KI, for elucidation of functional channels in models and human brain slices, pertinent to brain development in the immature and growing individual.
The foetus in utero develops the central nervous system (CNS) from the notochordthat folds upon itself to formt he cerebral hemispheres at the cephald end, the spinal cord at the caudal end, and the compact brainstem and midbrain in between. Disorders in neural migration in the second trimester lead to neuronal migration disorders, including heterotopias, focal cortical dysplasia, and even hemimegalencephaly. These may be detected in utero by foetal ultrasound and detailed by foetal MRI during gestation.
Postnatal brain development proceeds rapidly, with luxurious neuronal growth in the first year, but a pruning back of excessive synapses in the second year, putting the infant at risk for developmental disorders of maturation such as autism, epilepsy and cerebral palsy. Genetic and congenital conditions include spina bifida, Arnold-Chiari malformation of various degreees, or hydrocephalus. Exogenous viruses affect cerebral maturation , to the classical TORCH (toxoplasmosis, rubella, cytomegalovirus and herpes) must be added the more recent Zika virus, resultting in microcephaly and global developmental delay. Epileptic encephalopathies due to genetic or chromosomal disorders include Down syndrome, Rett syndrome, Prader-Willi syndrome, and a host of Autistic spectrum disorders.
Childhood and adolescence are characterised by rapid brain growth and gyral formation, with neurogenesis until the midtwenties, as language develops with psychomotor advances, rapid gains in memory and judgement, as the adolescent matures to an adult. There is often a quiescent peroid in late adolescence in phenotypic expression of the epilepsies, but he electroencephalography remains a valuable biomarker throughout life: from infancy to childhood, adolescence to adulthood into seniority and senescence, to brain death.
Parallel the tremendous brain maturation and connectivity are diagnostic methods of neuroimaging the brain, in structure, in function and in connectivity, techniques including computed tomography (CT) and positrion emission tomography (PET) for functional neuroimaging, SPECT scan for cerebral perfusion
studies, NMR or popularly, MRI for structures, and MRS for chemical changes in situ, in the alert, behaving human noninvasively and safely. Temporal events may be mapped to the nearest tens of milliseconds for transients, such as epileptic spike discharges, changes in background activity with sleep-wake cycles and the effects of exogenous toxins and drugs.
In the developed countries faced with the tsunami of neurodegenrative disorders that require chronic care but no cures, with advances in neurosciences in gene-therapies including geneediting , the rapid implementation of novel technology to meet an aging population seeking stabilisation of the human condition, if not an outright cure, in the developed countries and the youth of developing countries, it would be necessary to avert a demographic perfect storm of conflicting demands for limited resources in the global healthcare of the 21st century. In this context, neuroscience becomes an indispensable vital component of the global healthcare strategy.
Keywords: neuroscience, foetal development, dysgenesis, epilepesy, autism, neurogenesis, barin maturation, neuroimaging
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