Think Science: Memory - Dr. Isabel Muzzio

Editor's Notes

• #3: Why is the study of learning and memory is so important and so interesting? Diseases that impair memory: Alzheimer’s, Korsakoff’s syndrome…many millions every year in our ever-aging population. About 4-5 million with AZ just in the united states….. Developmental: Down’s syndrome, mental retardation too much memory? PTSD, other maladaptive behaviors that are learned philosophical issues: But besides all of these undeniably important clinical considerations, the study of memory is philosophically very interesting. Most of what we know is not innate, but must be learned through experience, and it is this capacity for learning (combined with the language that lets us share what is learned with others both today and in the future), that makes civilization and culture possible. Now, maybe some of you don’t think that’s a good thing, and I’d be happy to discuss that position with anyone who lives in a cave and hunts with pointed sticks. But not just civilization but our own sense of self is inconceivable without memory. Who we are consists largely of what and who we know. As Alzheimer’s disease so heartbreakingly demonstrates, to lose one’s memory is, in a very real sense, to lose one’s self. Even more fundamentally, the study of memory is important because this is one of two or three areas where we are most likely to finally bridge the gap between minds and molecules, to actually find what cells and connections correspond to a learned idea. What I’m telling you is, if the age-old philosophical problem known as the mind-body problem is to be solved, it is likely that it will be solved by a neuroscientist studying learning and memory.
• #5: The hippocampus is comprised by two regions. A dorsal region region receives most of the visual and preprocessed spatial information and A ventral region that connects to brain areas involve din anxiety and emotion. Most electrophysiological studies have been conducted in the dorsal area. These studies supported the role of the hippocampus in spatial coding. However, it is still not clear how emotions affect these spatial representations. Moreover, it is not know how the hippocampus conveys contextual gating of aversive events when the ventral area, which shows less precise spatial cells, is the one that connects to the emotional centers of the brain. In the first part of the talk, I will talk about findings that show how emotions modulate dorsal representations. In the final part of the talk I will show evidence that the ventral region can also provide contextual information.
• #7: What is known about declarative memory in mammals like us? A major clue for the field came from the study of the effects of brain injuries or surgery for epilepsy, and in particular, on one such case- the case of H.M. After removal of both of his hippocampi (and a part of the medial temporal lobes) as a treatment for his severe epilepsy, H.M. remained seizure free ever since. He has also remained “memory-free”: he never formed another new long term declarative memory again. His old memories are intact- that is, he does not have retrograde amnesia. But he does have severe anterograde amnesia. Other forms of learning, such as classical conditioning and other forms of procedural learning, are unaffected in H.M. Animal experiments damaging the hippocampus cause highly selective learning deficits. Showed that the hippocampus is important for storing declarative memories in humans, and for several types of learning in other vertebrates.
• #8: HM has what we call anterograde amnesia: the inability to form new memories. This is contrasted with what is termed retrograde amnesia: the loss of old memories, without an impairment of the ability to form new ones. Amnesia can be caused by accidents, strokes, or degenerative diseases like Alzheimer’s. In most cases, you don’t see pure anterograde or pure retrograde amnesia, but a mixture of the two- again, AZ is a good example of this. HM is usually described as having anterograde amnesia, but in fact he also has some retrograde amnesia too.
• #13: The hippocampus is comprised by two regions. A dorsal region region receives most of the visual and preprocessed spatial information and A ventral region that connects to brain areas involve din anxiety and emotion. Most electrophysiological studies have been conducted in the dorsal area. These studies supported the role of the hippocampus in spatial coding. However, it is still not clear how emotions affect these spatial representations. Moreover, it is not know how the hippocampus conveys contextual gating of aversive events when the ventral area, which shows less precise spatial cells, is the one that connects to the emotional centers of the brain. In the first part of the talk, I will talk about findings that show how emotions modulate dorsal representations. In the final part of the talk I will show evidence that the ventral region can also provide contextual information.
• #14: IN COLLABORATION WITH ROBIN YUAN!