August 11, 2011
When You Can Recite A Poem But Not Remember Who Asked You To Learn It A Few Days Earlier
Damage to hippocampus very early in life hinders recollection of specific events but spares acquisition of general knowledge
Memory is not a single process but is made up of several sub-processes relying on different areas of the brain. Episodic memory, the ability to remember specific events such as what you did yesterday, is known to be vulnerable to brain damage involving the hippocampus. The question is, what happens when damage to the hippocampus occurs very early in life? In a case study published in the September 2011 issue of Elsevier's Cortex, clinical neuropsychologists have reported that a child can develop normally despite severe damage to the hippocampus resulting from lack of oxygen in the first days of life. This supports the theory that the different aspects of memory rely on distinct areas of the brain.
Analysing MRI scans of VJ's brain, Dr. Philippe Maeder found very severe atrophy (wasting away of brain tissue) in the hippocampi, while the adjacent area of the brain, known as the perirhinal cortex, was relatively spared from damage. This latter area is hypothesised to be important for the acquisition of semantic memory. These findings lend support to the idea that episodic memory (but not semantic memory) depends on the hippocampus.
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