Technology in Brain Research September 25, 2017

Discuss the use of brain imaging technologies in investigating the relationship between biological factors and behavior

An Introduction to Brain Scanning What does Daniel Amen say that we have learned from brain scanning technology?

Studying the Brain

Early Studies on the Brain In the past the study of the brain was limited to people suffering from head injuries and the effects of accidental damage. It was only possible to study the brain by carrying out an autopsy. Laboratory research with animals eventually resulted in important discoveries about causes and possible treatments of neurological and mental disorders. Research using live animals must now follow ethical rules. Physiological psychologists have a range of research techniques to study the function of the brain and body that could not have been imagined just a few decades ago- for example, ways to identify neurotransmitters and taking pictures of particular ions entering neurons when the appropriate ion channels open. It is also possible to study the activity of the brain through neuro-imaging.

Broca and Wernicke (7 min, 30 sec) Broca (1861) found that people suffering from damage in an area that was eventually called the Broca’s area are unable to understand and make grammatically complex sentences. Their speech consists almost entirely of content words. Wernicke (1874) first described the area that appears to be crucial for language comprehension. People who suffer from damage to Wernicke’s area are unable to understand content words while listening, and they are unable to produce meaningful sentences. Both researchers used autopsies to study the brain in patients who had suffered from strokes.

Modern Brain Imaging

Contributions of Brain Imaging and Psychology We can study the living brain, rather than waiting for the individual to die so that we can do a post-mortem. Death changes the nature of the brain, as does the treatments of the individual prior to death. It also means that we don't have to wait. It is much more time efficient. Brain imaging is much more ethical than the killing of animals to see their brains.

Types of Brain Imaging

Structural Imaging: MRI Strengths and limitations of MRI Scans MRIs are non-invasive, unlike the PET scan. Less expensive than PET and better temporal resolution. This means that the image is taken several times and then made into a composite image. This composite image is often lacking in precision and clarity, but is better than the PET scan. Research is correlational. Causation cannot be established. IB Studies involving MRI Scans: Corkin's study of HM Maguire's study of London taxi drivers and the size of hippocampi Thompson's study of localized classically conditioned responses in the cerebellum. Ashtari et al (2009) on whether substance abuse can damage the developing brain in adolescents Structural Imaging: MRI The MRI (Magnetic Resonance Imaging) gives a three-dimensional picture of the brain structures. MRI detects changes in blood flow without using a radioactive tracer. It uses magnetic fields and radio waves. It exploits the fact that some substances that make up the body have intrinsic magnetic properties and respond to being in a magnetic field, rather as does a compass needle. When a magnetic field is passed over the head, reverberations are produced by hydrogen molecules, and these are picked up by the scanner which converts the activity into a structural image.

Structural Imaging: fMRI Strengths and limitations of fMRI Scans fMRIs are non-invasive, unlike the PET scan. Creates a 3D image of the brain. Research is correlational. Causation cannot be established. IB Studies Involving fMRI: Harris & Fiske (2006) on responses to extreme out-groups. Fisher et al (2003) study of neurobiological study of attraction Baumgarten et al. (2008) on the role of oxytocin on trust Ramachandran's research on neuroplasticity and phantom limb syndrome Kim & Hirsch on bilinguals Structural Imaging: fMRI Unlike the MRI which shows the structure of the brain, the fMRI (Functional Magnetic Resonance Imaging) indicates activity in the brain. In a sense, it works like a film. The fMRI scanner measures changes in blood flow in the active brain.

Structural Imaging: PET Scans Before a PET (Positron Emission Tomography) scan begins, a patient is given a safe dose of a radioactive tracer compound and a modified glucose molecule (FDG). The injected FDG enters the bloodstream, where it can travel to the brain. The PET scanner measures energy that is emitted when positrons (positively charged particles) from the radioactive material collide with electrons (negatively charged particles) in the person's brain. The result is a picture showing which parts of the brain were most active. PET scans provide precise localization of brain activity, which is of great interest to psychologists studying the correlations between brain activity and cognitive processing. Strengths and limitations of PET Scans PET can gain information about the brain structure and function of conscious patients who may be able to perform psychological tasks. The scans are reliable and provide quantitative as well as qualitative data for the researcher. The PET scan is very expensive The PET has relatively poor spatial resolution It also requires a small amount of radioactive material be injected into the participant. This in and of itself is not dangerous, but it is still radioactive and is a risk to which the participant would otherwise not be subjected. IB Studies Involving PET Scans: Raine et al study of murderers who had pleaded not guilty for reason of insanity. Found lower activity in the pre-frontal cortex; asymmetry in the amygdala and the hippocampus. Blair et al (1999) revealed impaired pathways between the amygdala and the frontal lobe in psychopaths. Research on Alzheimer's disease (eg. Mosconi, 2005)

Critical Issues with Brain Imaging The environment is unnatural and may influence the outcome of the research. Claustrophobia and obesity Colors exaggerate the effects of the brain. Argues for brain localization rather than neuroplasticity Brain images are compilations. Imaging takes place over time, rather than a specific moment Scanning is more ethical and more practical than past data gathering techniques. Emailing brain scans allows researchers around the world to collaborate on findings

For Tomorrow Read Oxford Pages 46-47 Read Pearson Page 49 Google Classroom Assignment on Brain Localization due Wednesday