Thursday, May 19, 2011

Brain Anatomy....Hippocampus


julieyumi:

The amygdala, named in Latin after its likeness to an almond, is located in the brain just in front of the hippocampus.  This is ideal because the amygdala attaches emotional significance to memories, which the hippocampus processes.
While the amygdala is best known and understood for emotional reactions (I.E., rage), when bitemporally lesioned (damaged in both hemispheres), patients tend to not only present with docility, but also hypersexuality with unusual objects and an odd tendency to put objects in their mouths.  This is known as Kluver-Bucy Syndrome.


The amygdala, named in Latin after its likeness to an almond, is located in the brain just in front of the hippocampus.  This is ideal because the amygdala attaches emotional significance to memories, which the hippocampus processes.
While the amygdala is best known and understood for emotional reactions (I.E., rage), when bitemporally lesioned (damaged in both hemispheres), patients tend to not only present with docility, but also hypersexuality with unusual objects and an odd tendency to put objects in their mouths.  This is known as Kluver-Bucy Syndrome.


The Hippocampus
This plays an important role in memory, as demonstrated by the famous case of H.M, a 27 year old patient who was suffering from severe temporal lobe epilepsy. As treatment, doctors surgically removed a region of both his medial temporal lobes which included the hippocampus. The treatment was successful in stopping most of the seizures. However, H.M. experienced a disastrous side-effect from the surgery; he became unable to form new memories.
 Damage to the hippocampus can produce both anterograde and retrograde amnesia but will not affect other aspects of memory, such as the ability to learn new skills (procedural memory) or to store information about meaning and facts (semantic memory).
The hippocampus is also believed to play an important role in storing information about the environmental (spatial) context of events that have happened in the past. Damage to this region is associated with difficulties in navigating through familiar places.


The Amygdala
This is often referred to as the "emotional brain" as it is believed to regulate a large number of emotional states. It is particularly associated with fear and anger.
The amygdala is also thought to be involved in emotional and autobiographical memory. It has the task of identifying the emotional significance of an event and making the event better remembered.


The Mammillary Bodies
These structures relay information from the amygdala and hippocampus to the thalamus. Damage here can impair memory.

The Olfactory Bulb
This controls the body's sense of smell and sends its signals back to the temporal lobes. It is involved in odor detection and discriminating between different smells. This structure also plays a role in emotional memory as distinctive smells are often associated with the memory of an event.

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