Infographic 6.2: Tracking Memory in the Brain

The introduction reads as follows: Whether with lab rats or case studies, psychologists have spent decades tracking the location of memory in the brain. What they’ve found so far should be no surprise: Memory is a complex system involving multiple structures and regions of the brain. Memory is formed, processed, and stored throughout the brain, and different types of memory have different paths. So to find memory in the brain, it helps to know your way around the brain’s structures. Remembering the amygdala’s role in processing basic emotion, for instance, can help you understand its role in processing the emotional content of memories. A frame at the left is titled, “Forming New Memories.” The text reads as follows: After his death, H.M.’s brain was cut into over 2,000 slices that were preserved and digitized for research. In an attempt to control the disabling seizures of a man named Henry Molaison (H.M.), doctors surgically removed portions of his brain, including the hippocampus. The surgery affected H.M.’s memory. He had profound anterograde amnesia: He could tap into old memories, but he could no longer make new explicit memories. However, he could still create implicit memories. Using information gathered about H.M.’s brain, scientists have been able to directly connect the hippocampus to the creation of new explicit memories. An image shows a digital slice of a brain and the hands of a worker wearing gloves and holding a brush. The caption reads, “After his death, H.M.’s brain was cut into over 2,000 slices that were preserved and digitized for research.” A frame at the bottom is titled, “Storing Memories. The text reads as follows: Through his experiments slicing the cortices of rats that had learned to navigate mazes, Karl Lashley concluded that complex memories are not localized to a particular region in the cortex, but are instead widely distributed. Later research has established the interrelated roles of specific structures in the process of encoding, storing and retrieving memories. In a process called memory consolidation, which occurs in the hippocampus, memories are moved to other parts of the cerebral cortex for long-term storage. Research on this topic is ongoing. For instance, scientists have been able to link explicit memory storage to areas of the brain where the original sensation was processed (see Harris, Petersen, & Diamond, 2001). The graphic shows three sketches of a rat brain, with areas marked at the back and bottom of the sketches. The callout reads, “Lashley kept a careful record of the sizes and locations of lesions made in each rat as part of his experiments.” A graphic of the brain facing left shows callouts to different areas. Three callouts are to areas involved in memory creation, and include the following:

  1. Amygdala—implicit memory formation, emotional memory formation
  2. Hippocampus—explicit memory formation
  3. Cerebellum—implicit memory formation

Six callouts are to areas involved in memory storage, and include the following:

  1. Visual cortex—visual memory storage
  2. Temporal lobes—spatial memory storage
  3. Prefrontal cortex—working memory essential for retrieval
  4. Hippocampus—memory consolidation
  5. Cerebral cortex—memory storage distributed throughout
  6. Auditory cortex—auditory memory storage