June 21, 2017 By Dana Foundation in Books, Dana Alliance for Brain Initiatives, Neuroeducation Tags: A Day in the Life of the Brain, anxious, Behave The Biology of Humans at Our Best and Worst, Cerebrum, DABI, Dana Alliance, Elena Cattaneo, Gordon Shepherd, Joseph LeDoux, Kay Redfield Jamison, Mark Schatzker, Neuroenology: How the Brain Creates the Taste of Wine, New York Times, NPR, Patricia Bosworth, Robert Lowell Setting the River on Fire, Robert Sapolsky, Summer Reading, Susan Greenfield
A New York Times profile earlier this week on Brenda A. Milner, Sc.D., credited her with changing “the course of brain science for good as a newly minted Ph.D. in the 1950s by identifying the specific brain organ that is crucial to memory formation.”
Milner, a Dana Alliance for Brain Initiatives member, identified the hippocampus and other areas of the brain that process memory while working with Henry Molaison, more commonly known as H.M., who developed amnesia at age 29 from the removal of tissue from both his medial temporal lobes, a surgery that was supposed to alleviate his epilepsy.
With the help of H.M., Milner discovered that memory was processed in the medial temporal lobes, which was why he could no longer form new long-term memories. He was, however, able to learn new tasks, meaning he must remember the actions in another part of the brain. His ability to acquire new skills proved to Milner there are two types of memory that occur in different parts of the brain – explicit memory, which recalls describable details like facts and events, and implicit memory, for unconscious memories such as actions and procedures. Milner described this finding in a 2010 Dana Foundation interview:
I went to the McGill psychology department and borrowed learning tasks to give him [H.M]. I took down a maze task, which I was sure he wouldn’t learn, and he didn’t. It was a nice control test, because he showed absolutely no progress over three days. Then I gave him the mirror drawing task. H.M. did 30 trials over three days and at the end of the last trial, his performance was absolutely perfect. I can still remember him looking at what he had drawn, saying: “This is strange. I thought this would be difficult, but it looks as though I’ve done it rather well.” I was very excited because it showed that he could have this excellent performance without any awareness that the reason he was doing so well was that he had had the chance to practice the task over three days.
When I saw that H.M. had this beautiful learning of something he had no memory of having acquired, I then speculated that this task, which involved motor learning, depended on a different system in the brain. His surgeon had damaged his medial temporal system, but this was a kind of learning that was unaffected by this operation, so therefore it must involve other structures.
“Suppose you were to go back to the place where you lived as a child,” neuroscientist Richard Morris prompts, “You could probably go back to the exact spot where the house was, but it may have changed dramatically…It may be a whole different kind of neighborhood. But you would know that was the place where you had grown up.”
So what happens in our brains to give us this innate sense of place? Morris has devoted the last 50 years to researching and understanding the mechanisms in our brain that power this “internal GPS” and offered some insight on Tuesday’s episode of BBC Radio’s “The Life Scientific.” His work focuses on how brain connections change, strengthen, and weaken in response to patterns of activity that correspond to everyday life experiences.
Many factors weigh into how we perceive the world, and last night we tapped into two areas: hearing and memory, at a “Pint of Science” gathering at DROM in the East Village. Beer in hand, attendees packed the venue, eager to learn more from hometown scientists James Hudspeth of Rockefeller University and Paula Croxson of Mount Sinai.
Hudspeth, a Dana Alliance member and hearing expert, spoke about how hearing works, and the role of tiny hair cells in the cochlea. As explained on his Howard Hughes Medical Institute page, “Each cochlea normally contains about 16,000 hair cells, which convert mechanical inputs derived from sounds into electrical signals that the brain can interpret.”
It is the loss of these hair cells, which don’t regenerate in humans, that leads to the most common form of hearing loss, said Hudspeth. Lucky for us, other species can regenerate these cells (amphibians and reptiles, for example). Dr. Hudspeth is using zebra fish in his lab to study this ability; he hopes new therapies can be produced for people in the next five to ten years. In the meantime, cochlear implants are being used by more than 300,000 people in the US.
Our body is regulated by an invisible clock that influences our wakefulness, sleep, thoughts, and emotions. The circadian clock is an important regulatory feature, yet neuroscientists still don’t completely understand it. Although cognitive tests can be performed, it was difficult to monitor brain cells over the course of a day until neuroscientist and Dana Alliance member Huda Akil, M.D., designed an experiment that gave a new perspective on circadian clocks.
“Maybe it’s simple-minded, but nobody had thought of it,” she said to The New York Times in a recent article. Her team examined the healthy brains of 55 donors who had died suddenly at different times of the day. As reported by the Times:
As each person died, his brain cells were in the midst of making proteins from certain genes. Because the brains had been quickly preserved, the scientists could still measure the activity of those genes at the time of death.
Most of the genes they examined didn’t show any regular pattern of activity over the course of the day. But they found that more than 1,000 genes followed a daily cycle. People who died at the same time of day were making those genes at the same levels.
The findings were so consistent that they even enabled the scientists to determine the time of death within the hour.