Explain how environmental processes can affect one physiological process.

PSYCHOLOGY IB RSA Academy DR. Higgs-Allen Hassan AlSaffar

(With reference to empirical research studies)

Brain plasticity, also called neuroplasticity, is a common term used by neuroscientists, referring to the brain's ability to constantly change, grow, and remap itself over the course of a lifespan at any age – for better or worse. That such distinctive attribute makes the brain a quite even more valuable organ, as it can regularly adapt itself to deal with new inputs such as knowledgeable phases (gaining knowledge) and / or real life phases (environmental demands). Majorly there are several different types of brain plasticity. The first occurs when new-born babies are born and start developing into children. Studies have shown that the immature brain grows and creates at an unparalleled frequency, as the brain is submerged with new sensual contribution from the outside world.

Identified in 1965, that human brain structure was thought to be determined by genetics and thus fixed and unchangeable. But an experiment carried out by Hubel and Wiesel 1965, demonstrated that the brain could change in structure as a response to an environmental impact. The results of experimental studies were based on laboratory experiments with rats but it is now generally accepted that environmental enrichment can adjust the brain, particularly in the cerebral cortex, known as the area of higher cognitive functioning. It appears that the human brain is constantly changing as a result of experience throughout lifetime, as the brain changes with age to reflect new experiences and actions. In addition, the brain demonstrates tremendous plasticity in the wake of injury.

Neuroplasticity functions in two directions; basically it is responsible for deleting old connections as frequently as it enables the creation of new ones. This particular progression called “synaptic pruning” connections that are inefficient or occasionally used are allowed to be removed away, while neurons that are highly routed with information will be preserved, strengthened, made even more synoptically dense. Closely tied in with the pruning process, then on, is the ability to learn and to memorise, While each neuron acts independently, learning new skills may require large collections of neurons to be active simultaneously to process neural evidence; the ...

This is a preview of the whole essay

Mainly there are two effects of the environment, the environmental effects on dendritic branching (development of connections between neurons in the brain), and (2) the role of environmental stress on the hippocampus in prolonged stress (PTSD). The environment (e.g. access to toys or the company of other humans) provides opportunities and challenges to the brain. The brain is formed by all experiences, whether positive or negative. Brain plasticity refers to the brain’s ability to develop and form new connections as a result of experiences. Stimulation (or the lack of it) is known to influence number of neurons in the brain (dendritic branching) in the developing brain. Environmental stressors may influence the body’s stress system and contribute to structural changes in the hippocampus, e.g. in relation with PTSD.

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 nervous system of the brain, and stimulating environments will result in increased numbers of synapses (brain plasticity). Gopnick et al. (1999) that 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. little or no experience of language, touch and interaction with other humans. This is observed in children who were adopted from Romanian orphanages in the early 1990s. The brains of neglected children are often smaller and there is scientific evidence of altered brain function, such as intelligence and emotions.

Prior to Rosenzweig, Bennet & Diamond (1972) research, the role of environmental stimulation on brain plasticity. Investigating if environmental factors such as a rich or an

Impoverished environment affect development of neurons in the cerebral cortex. Rats were placed in either an enriched environment (EC) or impoverished condition (IC). Within enriched condition: 10-12 rats in cage provided with different stimulus objects to explore and play with. This group also received maze training. While impoverished condition, each rat in individual cages (isolation and no stimulation). The rats typically spent 30 to 60 days in their respective environments before they were put down so the researchers could study changes in brain anatomy. The research shows results that the anatomy of the brain was different in the EC and the IC. The brains of EC rats had (1) increased thickness and higher weight of the cortex in EC rats. (2) EC rats had developed more acetylcholine receptors the cerebral cortex important neurotransmitter in learning and memory.

Further discussing the results, the thickness of the cortex increased as a result of an enriched experience and it appeared that brain weight could change. This was an important finding. Follow-up of this research indicated that just 2 hours a day in an enriched environment produced same plastic changes in the brain as in rats that had been constantly within an enriched condition. This shows that the brain can change and adapt to new inputs that surrounds it. Since brain plasticity is assumed to follow the same pattern in animals and humans the implications of the study are that the human brain will also be affected by environmental factors such as intellectual and social stimulation.

Evaluation and Conclusion

The experiment was a thoroughly controlled and well organised laboratory experiment so it was possible to establish a cause-effect relationship. This experiment uses animals and therefore it might be difficult to generalize it on humans unless research with humans provides the same results. The research results have been replicated many times so it is now a well-established fact that an enriched environment provides a much better background for brain development than a poor environment. There are other ethical issues, such as in the use of animals in research like this. The rats in the IC were perhaps suffering from boredom but they were not harmed. The rats were killed after the test period in order to study changes in the brain. Since the results contributed to a much better understanding of the role of environmental factors in brain plasticity it can be argued that the research was justified in unkindness of the ethical issues.

References