Evaluations - A03

• Strength of plasticity - evidence from animal studies for brain's ability to change as result of experience. Kempermann investigated whether enriched environment alter number of neurons in brain, found evidence of increased number of new neurons in hippocampus (bit of brain associated with formation of memories) of rats housed in complex environments compared to rats housed in lab cages. Demonstrates brain often changes structure in response to type of environment exposed to, therefore increases validity of plasticity.

  COUNTER - not generalisable to humans, more complex than animals
• Strength of plasticity - support for functional recovery, Hubel & Weisel sewn cats eyes shut in order to analyse brain cortical responses, found area of visual cortex that processes information from shut eye was not idle as predicted but continued to process information from open eye. Visual cortex for sewn eye should have remained idle in absence of visual stimulation but rewired itself to take on functioning of different part of brain supports functional recovery. Therefore, increases validity of FR in helping brain functioning.
• Strength of FR - support from animal studies. Tajiri evidence for role of stem cells in recovery from brain injury, randomly assigned rats with traumatic brain injury to one of 2 groups. One group received transplants of stem cells into region of brain affected, three months after brain injury brains of stem cell rats showed development of neuron like cells in injury area. Supports stem cells role in FR and healing brain recover from trauma, also applied to treatments shows stem cells implanted accelerate recovery from brain damage. Thus, increases validity.

  COUNTER - humans more complex
• Strength of plasticity & FR - practical applications, understanding FR help appreciate spontaneous recovery of brain fast initially, tends to slow down with time. Developed therapies improve rate of recovery when it slows down, eg electrical stimulation of damaged part of brain make up for lack of stimulation, activity in area; further accelerate rate of FR or other techniques such as physiotherapy help too. Shows unlike brain has ability to fix itself partly, accelerated through application of plasticity and FR research demonstrating usefulness improving lives. Therefore increases validity.