SLP528 Neurology

The prefrontal cortex of the frontal lobe controls emotions, and the amygdala processes them; this statement explains the result of Phineas Gage’s accident, and why he ended up with a different personality. Furthermore, there are several cortical and subcortical structures which control emotion as well as some memory function. The cingulate gyrus, the amygdala, and the hippocampus are a few structures involved in the limbic lobe of the brain. The Papez Circuit, developed by James Papez (1937), is known as the pathway to process emotion in the limbic system:

 

 

 

 

 

 

 

 

 

 

 

 

 

 

The cingulate gyrus makes associations between stimuli to result in an emotion; for example, smelling cookies leads to a happy feeling due to a prior experience where cookies made you feel happy.

 

Robust associations may be present for a long time:

 

Next, the amygdala fear conditioning circuit has to do with emotions being taught and associations that may be linked with these particular emotions:

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

The hippocampus controls declarative memory. This includes memories that are formed, and later retrieved.

 

Real Life Situation: Henry Gustav Molaison (HM) had his hippocampus removed in the hopes of diminishing his epilepsy. Post operation, he was seizure free, however something peculiar happened. He was no longer able to create new memories. He was diagnosed with anterograde amnesia, or the inability to make new memories. HM was able to remember motor skill, or procedural memory, however he was completely unable to produce declarative, or semantic memory of facts and knowledge. (Anterograde amnesia is not to be confused with dementia, a progressive neurological disease.)