Physiology and behavior: Localization of function

• Explain one study related to localization of function in the brain.

The Brain

Explain one study related to localization of function in the brain.

Studies• Scoville and Milner• Maguire et al.

Terms• Phrenology• Tan• Broca’s Area• Broca’s Aphasia• HM• Wernicke’s Aphasia• Hippocamous

Early investigation of localization of function

Phrenology• The attempt to make

inferences about ones personality and intelligence by examining skull formation.

• Done by manually searching for bumps and indentations. Franz Joseph Gall

In general….• If there is a bump or

protrusion in that area it indicates MORE of that ability or trait.

• If there is an indentation it indicates a deficiency of that ability or trait.

Phrenology?

• Do you think it is a valid science?

• Work was picked up by Cesare Lombroso

• These ideas, although dangerous, are still the basis behind modern day criminal profiling.

Case studies of people with naturally occurring brain damage

Phineas Gage

Paul Broca• Worked with a patient

he called “Tan”• “Tan” could only say the

word “Tan”• “Tan” died

Broca’s Area

• In post-mortem autopsy, Broca found damage in the left frontal area of Tan’s brain.

• Broca discovered the area of our brain that is responsible for making our mouth move during speech.

Broca’s Aphasia

• Aphasia means damage to a speech area of our brain.

• Very common in TBI or stroke patients.

Sarah Scott

Studies of individuals who have undergone brain surgery

Damage to the hippocampus and memory(The HM Study)

Scoville and Milner (1957)

• HM fell off his bicycle when he was 7, injuring his head.

• He began having epileptic seizures when he was 10.

• By the time he was 27 he had so many seizures he could not live a normal life.

The HM StudyScoville and Milner (1957)

• Scoville performed experimental surgery on HM to stop the seizures.

• Seizures did stop, but HM had amnesia for the rest of his life.

• We learned a whole lot from HM’s issues.

HM

• They removed parts of his temporal lobe.

• They took out a little too much and removed part of his hippocampus.

• Experienced both Retrograde and Anterograde Amnesia.

Memories and the Hippocampus

Retrograde Amnesia• Forget past.• It can be time period, event

or select person.

Anterograde Amnesia• Cannot form new

memories.

HM’s Memory• He could not transfer new

episodic or semantic memories (explicit memories) into his LTM.

• He COULD form new long-term procedural memories (implicit memories).

• He could carry on a normal conversation (working memory) but would forget it almost immediately.

OK…what actually happened to HM’s brain?

• Corkin (1997) gave an old HM an MRI

• He found missing parts of the temporal lobes and hippocampus and surrounding areas.

• These areas tend to be pathways for memory (highways for ACH).

What can be learned about the relationship between brain and memory with HM?

• Our memory system is specialized and complex.

• The hippocampus plays a critical role in converting memories of experience from STM to LTM.

• HM retained some memories, so hippocampus does not store the memories, but processes them.

Maguire et al. (2000)

• Aim: To investigate whether or not the hippocampus plays a role in human spatial memory

Maguire et al. (2000)Method:• London taxi drivers with a range of

age and experience were the participants because their work requires the extensive use of spatial navigational skills

• Matched pairs design: participants were age and gender matched with a control group

• Two different types of MRI scanning were used to assess how the brains of the taxi drivers differed from the control group

• Quasi experiment

Maguire et al. (2000)

• showed significantly more grey matter in both left and right hippocampi of the taxi drivers compared to the control group

Maguire et al. (2000)Evaluation:• No ethical implications• Only observed males• Only observed 16 matched

pairs• Nature vs. Nurture debate:

did the driving influence the change in the hippocampus, or did their larger than average hippocampus lead them to become taxi drivers?