* It was believed earlier that the brain was only influenced by genes and was unchangeable. We know now that the idea of environmental enrichment vs. deprivation can modify the brain. There are two effects of the environment on physiological processes. They are brain plasticity and environmental stressors and damage in the hippocampus region. *
* Effect 1: Environmental effects on dendritic branching (brain plasticity) *
Environmental stimulation refers to the way the environment provides stimulation in the form of social interaction and learning opportunities for animals and humans.
Experiences are processed in the brain's nervous system, and stimulating environments will result in increased numbers of synapses (brain plasticity). *
* An enriched environment is characterized by multiple opportunities to learn new things. Researchers have used animal models to study synaptic changes in the brain because it is not possible to use humans in deprivation experiments. *
* Instead researchers use case studies of children who have grown up in total neglect, i.e. with little or no experience of language, touch and interaction with other humans. The brains of neglected children are often smaller and there is scientific evidence of altered brain function (e.g. in intelligence and emotions) *
* Empirical Evidence:
* Aim: To investigate whether environmental factors affect development of neurons in cerebral cortex. * Method: Rats were placed in either an enriched environment (EC) or an impoverished condition (IC). In the EC, 10-12 rats were in a cage where they were provided with different stimulus objects to explore and play with. They also had maze training. In the IC, all of the rats were put in isolation and had no stimulation. They spend 30-60 days in their respective environment before they were killed so they can study brain changes in brain anatomy. * Results: The anatomy of the brain was different for rats in the EC and the IC. The brains of EC rats had increased thickness and higher weight of the cortex and developed more acetylcholine receptors in the cerebral cortex. This neurotransmitter is important for learning and memory. * Evaluation: Since this experiment was rigorously controlled lab experiment it is possible to think to establish a cause-effect relationship. The use of animals for research is an ethical issue but since its not ethical to conduct this experiment on humans this is a better choice. There is also a problem with generalization because this was conducted on animals it’s difficult to generalize to humans unless there was research with human which provided similar results. The research challenged the belief that brain weight cannot change <-- important finding. *
* Effect 2 : Environmental stressors and hippocampal damage in PTSD patient *
* A stressor is any event that threatens to disrupt the body's normal balance and starts a stress response such as secretion of stress hormones and activation of the 'fear sensor' in the brain, the amygdala. * A stressor may be an acute stressor (e.g. being assaulted, having an accident) or it could be a chronic stressor (e.g. anticipation of violence or worrying). * The fight or flight response (coping mechanism) is a pattern of physiological responses that prepares the body to deal with emergency. Sapolsky (1996) has shown in animal studies that long-term stress and a prolonged flow of cortisol can influence the size of the hippocampus, which plays a major role in memory. *
* Trauma and PTSD
* Traumatic episodes (i.e. frightening situations from which a person cannot escape) produce intense fear. In about 5% of the population this may lead to PTSD (post-traumatic stress disorder) with effects that can last for a brief period or a lifetime. * Combat veterans and survivors of childhood sexual abuse who suffer from PTSD tend to have a number of...
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