Case Studies and Their Implications

Question 1

Phineas Gage

Answer 1

• Phineas Gage was a railway worker, who suffered an accident in which an iron rod was propelled through his skull by an explosion - causing significant damage to his frontal lobe. His case is credited with significant contributions to our understanding of the localization of certain brain functions and the relationship between the brain and behaviour.
• (Damasio, 1994) - The popular account of the behavioural changes that followed his accident were that he used to be a reliable and well-liked individual, and became a reckless, unreliable, irresponsible and sexually promiscuous individual afterwards. He no longer showed respect for social convention - attributed solely to damage to the vMPFC.
• It may be unwise to attribute these changes solely to damage to the vMPFC - when they were likely influenced by a diverse range of other factors (e.g., additional brain damage due to surgery, degenerative epileptic fits, shock/trauma, stigmatization because of disfiguration etc.,).
• (Harlow, 1848) - Gage’s physician, Inclined to phrenology. Described his personality as permanently changed.
• (Bigelow, 1850) - Anti-localizationist and a Harvard professor. Described Gage as fully recovered, both psychologically and physically.
• A modern understanding would suggest that Gage was unlikely to have been irrevocably changed into a psychopath or refined to psychopathy-like behaviours (e.g., brain plasticity, neurorehabilitation)

Question 2

Patient H.M.

Answer 2

• Possibly the best known case study in the history of neuroscience. Helped to establish fundamental principles about how memory functions are organized in the brain (Squire, 2009)
• Developed amnesia at age 27 after undergoing brain surgery to treat epilepsy. Large parts of the hippocampus in both hemispheres were removed (a lesion of the medial temporal lobe) - the result being that he was almost entirely unable to store any new information in long-term memory (only almost - Corkin, 2002)
• Extremity of his deficits challenged the thinking at the time - because the popular perspective was that memory was distributed throughout the cerebral cortex.
• (Scoville & Milner, 1957) studied him - this original paper: (1) informed neurosurgeons that a bilateral lesion of medial temporal lobe structures placed recent memory functions at risk, (2) suggested that the establishment of memory had a distinct neural substrate (memory for new experiences was disturbed, but other cognitive functions and sensory capacities were unimpaired).
• The animal models of human amnesia and human studies that followed demonstrated that medial temporal lobe structures are critical for establishing long-term declarative memory (type of memory that involves consciously recalling facts and events - sometimes called explicit memory)