Discuss two effects of the environment on physiological processes Flashcards
Name two effects of the environment on physiological processes (2)
- Effect 1: Environmental effects on dendritic branching (brain plasticity)
- Effect 2: Environmental stressors and hippocampal damage in PTSD patients
Effect 1: What does environmental stimulation refer to? (1)
- the way the environment provides stimulation in the form of social interaction and learning opportunities for animals and humans
Effect 1: Where are experiences processed? What does this mean? (2)
- in the brain’s nervous system
- stimulating environments = increased numbers of synapses (brain plasticity)
Effect 1: What is an enriched environment characterised by? What have researchers used animal models for? Why? (3)
- multiple opportunities to learn new things
- to study synaptic changes in the brain
- because it is not possible to use humans in deprivation experiments
Effect 1: “ it is not possible to use humans in deprivation experiments” What do researchers use instead? (1) What do these show? (2)
- 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
- brains of neglected children are often smaller and there is scientific evidence of altered brain function (e.g. in intelligence and emotions)
Effect 1: AMFCE Rosenzweig, Bennet and Diamond (1972) the role of environmental stimulation on brain plasticity (14)
Aim: to investigate whether environmental factors such as a rich or an impoverished environment affect development of neurons in the cerebral cortex
Method:
- rats placed in either enriched environment (EC) or impoverished condition (IC)
- EC: 10-12 rats in a cage provided with different stimulus objects to explore and play with. Also received maze training
- IC: each rat in an individual cage (isolation and no stimulation)
- spent 30-60 days in their respective environments before they were killed so the researchers could study changes in brain anatomy
Findings:
- anatomy of brains = different for EC v IC
- brains of EC rats increased thickness and higher weight of cortex
- EC rats had developed more acetylcholine receptors in cerebral cortex = imp neurotransmitter in learning and memory
Conclusion:
- 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:
- rigorously controlled lab experiment = possible to establish a cause-effect relationship
- experiment used animal models = difficult to generalise to humans unless research with humans provides same results
- research justified by findings in spite of harm
- follow-up research indicated that just 2 hours/ day in EC produced same results as when rats had constantly been in EC = brain can change/ adapt to new situations
- research challenged belief that brain weight cannot change = important finding
Effect 2: What is a stressor? (1)
- 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
Effect 2: What are the 2 types of stressor (2)
- acute stressor: being assaulted
- chronic stressor: anticipation of violence/ worrying
Effect 2: What is the fight or flight response? (3)
- coping mechanism
- a pattern of physiological responses that prepares the body to deal with emergency
- Sapolsky (1996) has shown in animal studies that LT stress = prolonged flow of cortisol = atrophy of hippocampus which plays a major role in memory
Effect 2: What are trauma episodes? What do they produce? (3)
- frightening situations from which a person cannot escape
- produce intense fear
- in bout 5% of population this = PTSD which can last for a brief period or a lifetime
Effect 2: Who might suffer from PTSD? What do they tend to have? What has been observed in the brain of these patients? (3)
- combat veterans, survivors of childhood sexual abuse
- a number of stress related problems such as forgetfulness and difficulty learning
- stress-related physiological changes have been observed, esp in the hippocampus, which plays an important role in integrating different aspects of a memory at the time of recollection
Effect 2: AMFCE Environmental stressors and hippocampal damage in PTSD patients (12)
Aim: to measure the volume of the hippocampus based on the theory that prolonged stress may reduce the volume of the hippocampus due to increased cortisol levels
Method:
- MRI scans made of brains of participants and participants completed memory test (e.g. remembering a list of words)
- participants were veterans and female adults who had experience early childhood sexual abuse
- some had developed PTSD but not all
Findings:
- researchers found that there were deficits in STM and then performed MRI scans of the participants’ brains
- found that hippocampus was smaller in PTSD patients than in control group
- veterans with smallest hipp = worst memory problems
- findings showed clear correlation between number of years of abuse as measured by a trauma test, memory problems and hippocampal volume
- sufferers of PTSD often suffer from other psychological disorders (e.g. depression) which could perhaps also play a role in the observed changes in the brain
Evaluation:
- sample size very small = difficult to say anything definite about relationship between trauma and hippocampal volume
- could be alternative explanations to differences in hippocampal volume (e.g. PTSD sufferers often suffer from depression as well + depression is associated with reduction of hippocampus)
- however, findings of a large reduction of hippocampal volume in combat-related PTSD has been replicated many times
Discuss two effects of the environment on physiological processes
- Effect 1: Environmental effects on dendritic branching (brain plasticity) (10)
- AMFCE Rosenzweig, Bennet and Diamond (1972) the role of environmental stimulation on brain plasticity (14)
- Effect 2: Environmental stressors and hippocampal damage in PTSD patients (12)
- AMFCE Environmental stressors and hippocampal damage in PTSD patients (12)
