Discuss the use of brain imaging technologies in investigating the relationships between biological factors and behaviour.

Introduction

State what you are doing in the essay

• This essay will attempt to offer a balanced review of the use of brain imaging technologies in investigating the relationships between biological factors and behaviour 
  

State the different types of brain imaging technologies used at the BLA

• PET: Positron Emission Topography
  
• MRI: Magnetic Resonance Imaging 
• fMRI: functional Magnetic Resonance Imaging 
• EEG: Electroencephalogram
  
• CAT: Computerised Axial Tomography 
  
• Each method has its own advantages and disadvantages and are appropriate in varying situations

• Explain why Brain imaging technologies are used at the BLA
  
• Brain imaging technologies are methods used in psychology to examine the human brain. 
• They are particularly useful in neuropsychology
• As it provides an opportunity to study the active brain
• Allows researchers to see where specific brain processes take place
• Enables researchers to study localisation of function (specific areas of the brain are responsible for different functions) in a living human brain
• It also provides correlations between brain activity and behaviour – though it does not necessarily detail a cause-effect relationship.
  
  
• State the brain imaging technology being discussed
  
• In the following essay, the brain imaging technologies that will be discussed are MRI and PET scans, which will be investigated in terms of its role in investigating the correlations/relationships between biological factors and behaviour.

Body

Biological Factor 1: Neuroplasticity; Brain Damage Brain Imaging Technology 1: MRI Scans

• Introduce the physiological process of neuroplasticity 
  
• The first brain imaging technology, MRI scans, will be firstly investigated in its relation to the biological process of neuroplasticity. 
• Describe the MRI brain imaging technology 
  
• This technique uses magnetic fields and radio waves to produce 3D computer-generated images.
• MRI scans involve people to remove all metal objects and clothing where they lie within an MRI machine.
• It can distinguish among different types of soft tissue and allows researchers to see structures within the brain. 

Supporting Study: Maguire et al. (2000)

Introduce StudyConnection of study to question:

• An example of a study which utilizes MRI scans to investigate the relationships between biological factors and behaviour is a study conducted by Maguire et al. (2000). 
  

• Maguire hypothesised that full licensed taxi drivers in London would have a different hippocampi structure in their brains compared to “normal? people. 
  

• This was based on the knowledge that London taxi drivers must do a two-year training course where they end up being able to find their way around the city without a map. 
  
• MRI scans were used to scan the structure of their hippocampi, which were compared to already existing MRI scans of healthy males who did not drive taxis. 
  

Results: 

• Taxi drivers? left and right hippocampi had a larger volume compared to the non-taxi drivers. 
  
• Some parts of the hippocampi were smaller in the taxi drivers. 
  

Conclusions:

• Maguire concluded that there was probably a redistribution of grey matter in the hippocampi of taxi drivers due to the regular use of the spatial memory skills required to remember roads; the neurons are stronger in areas of the brain which are used most. 
  

• By using an MRI, Maguire was able to observe the structures in the brain and find a correlation between environmental enrichment on neuroplasticity, a physiological process occurring in the brain, particularly around the hippocampi region which then affects behaviour in terms of memory. 
  
• Maguire used MRI scans to investigate the structure of the hippocampi, which would not be able to be seen using other technologies such as an EEG or a PET scan. 
  
• Biological Factor: Brains areas, hippocampi 
  
• Behaviour: Remembering, Memory 
  

Supporting Study 2: HM - Milner and Scoville (1957)

Introduce StudyConnection of study to question: 

• Another study which utilizes MRI scans to investigate a physiological process is a study conducted by Milner and Scoville (1957). 

• HM suffered epileptic seizures after a head injury at age 9 
  
• Doctors performed surgery to stop seizures 
  
• Tissue from temporal lobe, and hippocampus was removed 
  
• HM suffered anterograde amnesia 
  
• He could recall information from early life but could not form new memories 
• HM was studied using an MRI in 1997 
  

Findings: 

• The brain scan showed that there was damage to the hippocampus, amygdala, and areas close to the hippocampus 
  

• By using MRI scanning technology, researchers were able to investigate the effects of biological factors on behaviour and make a correlation between certain brain areas and memory and other behaviour. 
  
• MRI scans were used to see the structures of the brain to determine the extent of brain damage 
  
• The structures would not be able to be clearly seen using other technologies such as EEGs or CTs. 

Biological Factor 2: Localization of Function/Brain Damage Brain Imaging Technology 2: PET Scans 

• Introduce the cognitive process of language
  
• The next biological factor which will be discussed with the brain imaging technology of PET Scans are brain interactions and functions.
• Describe PET brain imaging technology 
  

• PET scans require patients to be injected with a radioactive glucose tracer which shows the areas where glucose is absorbed in the active brain.
• More glucose metabolism means more brain activity.
• PET scans show a coloured visual display of brain activity; where radioactive tracer is absorbed
• Red indicates areas with the most activity 
• Blue indicates areas with the least activity 

Supporting Study 3: Tierney et al (2001)

Introduce Study --> Connection of study to question:

• An example of a study which utilizes PET scans to investigate the result of brain damage is a study conducted by Tierney et al. (2001). 
  

• To evaluate, using PET scans, the bilingual language compensation following early childhood brain damage 
  

• 37 year old man (known as MA) with normal speech functions who was participating in a normal speech study 
  
• It was discovered that he had a lesion in his left frontal lobe 
  
• Probably as a result of encephalitis he suffered at the age of 6 weeks 
• He had no significant long-term, clinically consequences 
• Both his parents were deaf and he used sign language at home from a very young age. 
  
• Researchers were curious to know if this might have had something to do with his ability to speak despite the brain damage (that should have prevented him from doing so. 
  

Methods: 

• Researchers compared MA to 12 control participants, who were fluent in sign language 
  
• PET scanning technologies were used while the participants produced narrative speech or signs 
  

Results: 

• MA's right hemisphere was more active than the controls' during the production of both speech and sign language