In this post, we’re going to talk a little about how memory loss happens and how you can stay safe. 

Keeping old memories, but not being able to make new ones (anterograde amnesia)

This includes things like: 

(1) Not remembering a person even if they left for only a short time.
(2) Not being able to learn anything new. 
(3) Not being able to form new relationships with people. 

To stop this from happening to you, you need to protect the midline of the region highlighted in the figure below:

This region is called the temporal lobe, and the midline is called the medial temporal lobe. You can imagine some physical ways to cause trauma to the medial temporal lobe. Things such as a hard hit around the ears, or a bad fall on the side or back of your skull. Other ways to cause damage to the medial temporal lobe includes strokes, tumors and alcoholism. 

Losing old memories, but keeping ability to make new memories (retrograde amnesia)

Well, losing old memories again involves damage to the temporal lobe, but not the midline or medial region. The medial region is only for new memories. For old memories, the damage has to be in the anterior and lateral regions, i.e. the front and sides. You would be dealing with things such as:

(1) Forgetting your name, loved ones and life, in the worst case
(2) Forgetting memories of the last 1 or more decades, in the “not so bad” case. 

Again, this damage could result from physical trauma or medical trauma. 

Newer findings

Although scientists agree that the lateral and anterior temporal lobe regions store most old memories, newer studies have shown that some older memories may be stored throughout the top part of the skull, a region called the neocortex. This region is highlighted in the image below:

As you can tell from the label – feel-remember –  most memory-related activity happens in the temporal lobe. Another thing to note is that the anterior and lateral sections (front and sides) of the temporal lobe are actually more a part of the neocortex, than they are part of the mid brain. 

Anyway, as I was saying, some older memories get stored in parts of neocortex that are not even that close to the anterior or lateral temporal lobe. Of course, these are isolated memories that are thought to have remained in the area where they first formed. So don’t be surprised if damage to the top part of your skull (the neocortex in general) has you forgetting certain old memories while being able to recall others.   

Summary of what you shouldn’t do to stay safe from memory loss 

(1) Always protect the outer regions of your skull
(2) Protect the area around your ears
(3) Protect the back of your skull
(4) Don’t increase the risk of stroke or tumors, and
(5) Don’t cause degernation of brain areas through substance intoxication. 

There are, of course, many more details than this, but we’re not here to expound the ins and outs of neurobiology. For the purpose of this post, this level of detail is plenty. Thanks for reading!