The following essay will define the terms ‘epigenetic’, ‘sensing pathways’ and ‘stress pathways’ and also explain the role they each play in brain development. Epigenetic can be defined as the effect of environmental factors on genes (Appalachia 2010, p. 5). We are all born with a set of genes which act as a blueprint for development. It is the environmental factors that we experience which alter how, where, when and even if genes are expressed (McCain Mustard & Swanker 2007, p. 20).
The study of epigenetic has revealed that our DNA Is not our destiny; nurture affects nature (University of California Television 2011). Our genes can be turned on or off dependent on environmental factors, without actually altering our DNA or genetic code (McCain Mustard & Swanker 2007, p. 30). These alterations can be passed on to other generations, with our descendents not only inheriting our genes, but the way they were expressed (Incentive 2008). There are many environmental factors which influence the way our genetic code is read, or which switches are turned on or off (McCain Mustard and Swanker 2007, p. 0). The experiences we have pre and post-notably with nutrition, teratology (including stress), family and members of the immunity interact with each person’s genetic potential, influencing not only long term brain function but also our physical and mental health (Router 2012; Trembler 2010, p. 1). The brain is a use-dependent organ which responds to patterned, regular experiences; the more a neural network Is activated, the more that part of the brain will change (Luda-Dobson ; Perry 2010, p. 27).
Early brain development Is particularly vulnerable to the environment be it positive or negative, impacting favorably or not on the processes of improvement’s (Perry 2002). The role epigenetic plays in brain development can be exemplified through the lives of identical twins. Identical twins have the same DNA but will encounter deferent experiences causing differences In gene expression (Mustard 2010, p. 1). Their genetic blueprint Is the same but the way It Is read Is different due to epigenetic leading to differences In behavior, learning and physical and mental health (Mustard 2010).
Epigenetic influences are vital to brain development. Many functions of our brains, including those that relate to sensing pathways such as vision, hearing ND touch, expect to receive sensory input for normal development to occur (Beer cited in Carlson 2006, p. 11; Mustard 2006, p. 1). Sensory input accounts for majority off humans learning In the first two years of life (Carlson 2006, p. 11) A sensing pathway can be defined as a ‘pathway for Impulses for a sensation’ connecting the brain to the body (McCain, Mustard camp; Swanker 2007 p. 2; Scandal & Sanders 2010, p. 234). Sensory pathways consist of receptors which detect changes in stimuli; sensory neurons which send this information to the central nervous system ND sensory tracts which transmit impulses to specific brain parts (Scandal & Sanders 2010, p. 34). Sensory stimulation Is vital in ensuring neurons form synapses development (McCain, Mustard & Swanker, 2007, p. 22). The importance of timing in relation to sensory input is made clear through studies of the relationship between cognitive development and nurturing care-giving.
Observation of Romania orphans who were not given early experiences through loving two-way interactions such as touch, talking, singing and gazing have shown that this type of emotional and social neglect can have severe life-long consequences on brain development. The Romania orphan babies are now adults who have brain damage and are unable to meet their own basic needs Innings 2005, p. 23). This example demonstrates that ‘an absence of nurturing during the first three years of life can lead to disorientation of neural systems that mediate social-emotional functioning (Luda- Dobson ; Perry 2010, p. 2). This line of research also reveals that the social environment we experience during the early years of life can have genetic implications on the formation of stress pathways within the brain (National Scientific Council on the Developing Child 2005, p. 2). Stress pathways can be defined as circuits and hormonal systems which generate reactions to sensory input which is threatening or unfamiliar. Early life experiences which promote a chemical and neural stress response influence the formation of the brain’s adaptive stress pathways (National Scientific Council on the Developing Child 2005).
Stress is a normal part of life, and learning to respond to stress is important in healthy development. ‘Positive stress’ which refers to responses which are mild and short in oration and feature the support of positive, caring and safe adult relationships supports normal development (National Scientific Council on the Developing Child 2005, p. 1). Starting preschool for the first time surrounded by warm and nurturing educators is an example of positive stress for a child. Tolerable stress also features the support of caring adults and is short-lived, but involves more serious experiences such as death and divorce.
While this type of stress can affect brain architecture, there is the potential for positive effects, dependent on the presence of supportive relationships. When stress is strong, and occurs regularly for a long period of time without the buffer of a caring adult relationship it becomes toxic. Toxic stresses such as neglect, emotional, physical or sexual abuse can cause changes to the architecture of the brain resulting in unhealthy patterns of stress regulation (National Scientific Council on the Developing Child 2010, p. 1).
