Teen Marijuana Users Have Poor Long-term Memory in Adulthood
Posted by on March 12, 2015 - 1:00pm

Teens who were heavy marijuana users – smoking it daily for about three years -- had an abnormally shaped hippocampus and performed poorly on long-term memory tasks, reports a new Northwestern Medicine study.  

The hippocampus is important to long-term memory (also known as episodic memory), which is the ability to remember autobiographical or life events.

The brain abnormalities and memory problems were observed during the individuals’ early twenties, two years after they stopped smoking marijuana.

Young adults who abused cannabis as teens performed about 18 percent worse on long-term memory tests than young adults who never abused cannabis.

“The memory processes that appear to be affected by cannabis are ones that we use every day to solve common problems and to sustain our relationships with friends and family,” said senior author Dr. John Csernansky, the Lizzie Gilman professor and chair of psychiatry and behavioral sciences at Northwestern University Feinberg School of Medicine and Northwestern Memorial Hospital.

The study was published March 12 in the journal Hippocampus.

Read more HERE.   Source:  Northwestern News
Menopause and Memory: Women Know What They Do Not Know
Posted by on August 8, 2013 - 3:24pm

The need for health care varies greatly over a lifespan, with older adults having significantly more health-related needs and costs than younger individuals. Women, in particular, often face a myriad of health problems as they transition through menopause.  Sadly, despite the fact that every woman will go through menopause, very little is understood about the physical and mental changes that occur during this period of life.  In addition, women may struggle to find pharmaceutical solutions, which can safely provide proven relief without the worry that those available will increase their likelihood of other health and mental complications.

Much is misunderstood about menopause and the changes that are associated with the hormonal fluctuations. This is largely due to the fact this inevitable transition is rarely apart of the conversation, particularly in the context of health care. Further, menopause is expected to be merely “bothersome”; not something one could attribute real health problems to. Although maternity care and issues related to younger women are required in the Affordable Care Act as essential health benefits, nothing of legislative note will improve the knowledge and acceptance of this natural life progression.

Most insurance companies do not even cover basic medications associated with menopausal symptoms, and conflicting research has women scared about the potential long-term effects associated with hormone replacement therapy. Negative press, little medical literature and low financial assistance often leaves women to suffer through menopause silently, many of whom worry constantly about memory deficits they experience and potential long term changes.

A recent study focused on the memory complaints of midlife women has been receiving a lot of attention. The study, conducted at the University of Illinois- at Chicago (UIC), attempted to determine if women who are experiencing hot flushes during menopause were able to accurately predict their own memory performance.

According to the principal author, Lauren Drogos, “We found that a one-item question: ‘How would you rate your memory in terms of the kinds of problems that you have?’ was the best predictor of verbal memory performance on a list-learning task.  We also found that many complaints were related to mood symptoms.”

In the US, the average woman becomes postmenopausal around the age of 51.  Common symptoms that occur include hot flushes, sleep disturbances, mood changes and memory problems. However, until recently it was believed that women were unable to accurately describe the current state of their memory and the changes they experience as they progress through menopause.

Despite the difficulty in being taken seriously about the physical and mental challenges that menopause presents, this recent study from Drogos, along with other research, shows that woman are able to accurately describe their current memory abilities. Specifically, a group of sixty-eight women performed a series of memory tests and were then asked, to detail the types of memory problems they were experiencing. The study concluded that women were able to accurately rank themselves on a scale from no memory problems to severe problems.

Using recall of a short story, the deficits seen in memory did not indicate that women were suffering from dementia, nor were they experiencing shortfalls in memory that were impacting daily life. Instead, it was simply indicative that women who experienced memory deficits often recognized the changes occurring.

Previous research focusing on women’s transitions through menopause also found that hot flushes during the nighttime were the best predictors of memory performance in women. This leads researchers within the Women’s Mental Health Research Program at UIC, to believe that sleep disturbances and stress hormones may play integral roles in memory and hot flushes.

The good news for women concerned about the transition through menopause is that the cognitive decline that occurs appears to only be temporary, with performance rebounding early into post-menopause. Further, for those who want to keep both their minds and bodies at peak performance, research indicates that leading a non-sedentary lifestyle, keeping mentally active, and having a healthy diet can be the best preventers of cognitive decline.  To learn more about menopause, visit menopausenu.org, a new web site that helps women evaluate their overall health and menopause symptoms.

Understanding brain signals may hold promise for treating post traumatic stress disorder (PTSD)
Posted by on May 5, 2013 - 12:35pm

When the mind is at rest, the electrical signals by which brain cells communicate appear to travel in reverse, wiping out unimportant information in the process, but sensitizing the cells for future sensory learning, according to a study of rats conducted by researchers at the National Institutes of Health.

The finding has implications not only for studies seeking to help people learn more efficiently, but also for attempts to understand and treat post-traumatic stress disorder — in which the mind has difficulty moving beyond a disturbing experience.

During waking hours, brain cells, or neurons, communicate via high-speed electrical signals that travel the length of the cell. These communications are the foundation for learning. As learning progresses, these signals travel across groups of neurons with increasing rapidity, forming circuits that work together to recall a memory.

During waking hours, electrical signals travel from dendrites — antenna-like projections at one end of the cell — through the cell body releasing chemicals at the other end, stimulating adjacent cells.. When groups of cells repeatedly fire in this way, the electrical signals increase in intensity.  Dr. Olena Bukalo and her team examined electrical signals that traveled in reverse from the cell’s axon, to the cell body, and out its many dendrites. The reverse firing, happens during sleep and at rest, appearing to reset the cell and priming it to learn new information.

It was previously known that, during sleep, these impulses were reversed. In the current study, the researchers found that these reverse signals weakened circuits formed during waking hours, apparently so that unimportant information could be erased from the brain. But the reverse signals also appeared to prime the brain to relearn at least some of the forgotten information. If the animals encountered the same information upon awakening, the circuits re-formed much more rapidly than when they originally encountered the information.

“The brain doesn’t store all the information it encounters, so there must be a mechanism for discarding what isn’t important,” said senior author R. Douglas Fields, Ph.D., head of the Section on Nervous System Development and Plasticity at the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), the NIH institute where the research was conducted. “These reverse brain signals appear to be the mechanism by which the brain clears itself of unimportant information.”

Their findings appear in the Proceedings of the National Academy of Sciences.

The researchers studied the activity of rats’ brain cells from the hippocampus, a tube-like structure deep in the brain. The hippocampus relays information to and from many other regions of the brain. It plays an important role in memory, orientation, and navigation.

A graphic illustration of a reverse firing neuron is available at: http://www.nichd.nih.gov/news/releases/Pages/031413-neurons-image.aspx.

Source:  NIH

 

Memory like the telephone game
Posted by on November 24, 2012 - 11:30am

Remember the telephone game where people take turns whispering a message into the ear of the next person in line? By the time the last person speaks it out loud, the message has radically changed. It’s been altered with each retelling.

Turns out your memory is a lot like the telephone game, according to a new Northwestern Medicine study.   Every time you remember an event from the past, your brain networks change in ways that can alter the later recall of the event. Thus, the next time you remember it, you might recall not the original event, but what you remembered the previous time. The Northwestern study is the first to show this.

“A memory is not simply an image produced by time traveling back to the original event -- it can be an image that is somewhat distorted because of the prior times you remembered it,” said Donna Bridge, a postdoctoral fellow at Northwestern University Feinberg School of Medicine and lead author of the paper on the study recently published in the Journal of Neuroscience. “Your memory of an event can grow less precise even to the point of being totally false with each retrieval.”

The findings have implications for witnesses giving testimony in criminal trials, Bridge noted.  “Maybe a witness remembers something fairly accurately the first time because his memories aren’t that distorted,” she said. “After that it keeps going downhill.”

The published study reports on Bridge’s work with 12 participants, but she has run several variations of the study with a total of 70 people.

“Every single person has shown this effect,” she said. “It’s really huge," said Bridge.   The reason for the distortion, Bridge said, is the fact that human memories are always adapting.

“Memories aren’t static,” she noted. “If you remember something in the context of a new environment and time, or if you are even in a different mood, your memories might integrate the new information.”

For the study, people were asked to recall the location of objects on a grid in three sessions over three consecutive days.  “Our findings show that incorrect recollection of the object’s location on day two influenced how people remembered the object’s location on day three,” Bridge explained. “Retrieving the memory didn’t simply reinforce the original association. Rather, it altered memory storage to reinforce the location that was recalled at session two.”

“This study shows how memories normally change over time, sometimes becoming distorted,” Bridge noted. “When you think back to an event that happened to you long ago -- say your first day at school -- you actually may be recalling information you retrieved about that event at some later time, not the original event.”

Author:   Marla Paul, Northwestern NewsCenter