The human brain consists of more than 100 billion neurons, which pass elec- trochemical signals to process and transmit information. Neurons communicate with each other at the structure called ”synapse”.
Impairments in neuronal communication can provide a framework for un- derstanding the brain disorders. Defects in synaptic functions might yield to neurological or psychiatric disorders such as schizophrenia, Parkinson’s disease, Alzheimer’s disease, addiction, compulsive disorder and autism spectrum disor- ders (ASDs).
This paper investigates some of the diseases respectively Schizophrenia, Autism and Addiction by discussing the recent evidence of malfunctions in synaptic transmission.
Literature Review
Schizophrenia
Pathophysiology
There is evidence from literature that shows reduced connectivity in schizophre- nia (Friston 2002). This may be the result of malfunctions in synaptic plasticity as LTP (Long Term Potentiation) is responsible for the development of dendrites and spine (Stephan, Baldeweg, and Friston 2006).
Altered function of the gene NRG1 that encodes neuregulin-1 and its receptor ErbB4 are also associated with the disease. High levels of NRG1 is observed in forebrain regions of patients with reduced activity of glutamate and GABA. Lin Mei and Wen-Cheng Xiong were able to observe behavioral deficits when they increased the levels of NRG1 of genetically engineered adult mice and they were also able to reduce the deficits as they decrease the levels of NRG1 by feeding them antibiotics (Yin, Chen, Lu, Bean, Sathyamurthy, Shen, Liu, Lin, Smith, Xiong, et al. 2013).
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N-methyl-d-aspartate receptors (NMDARs) has an essential role in synaptic plasticity and it is implicated in schizophrenia. Impaired NMDA receptor func- ti...
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..., Horan, Gardner, and Ashby 1999) and Brodie et al. were able to provide 80% reduction of cocaine administration in human subjects as well as reducing the cravings (Brodie, Figueroa, and Dewey 2003). These results shows that GABA concentration successfully reduces addictive behaviors and intake of addictive substances. Furthermore, GVG might even be used to to treat other diseases like schizophrenia to regulate dopamine levels and help with the symptoms.
Summary
Psychiatric and neurological disorders stresses the importance of synaptic func- tions and plasticity. With animal and human studies, progress has been made and knowledge about synapse pathology has been established. With growing technologies, it is essential to combine different research methods such as brain imaging methods and genetic studies to gain more information on the diseases and produce treatments.