How does your brain remember what you had for dinner last night

on 25 January 2018
No train, no gain

Scientists are getting closer and closer to understanding basic brain functions, i.e. how and why it does what it does. The most important of those, if only for the purpose of understanding our lives, is memory. In the meantime, we can practice different ways to improve our memory, with speed-of-processing training being mooted as a front runner!

The dynamic duo of memory, hippocampus and thalamus

It is fair to say that nowadays there is much more interest in our own health and much more information available to help us make informed choices. While there is definitely more emphasis on physical and dietary wellbeing, there is a growing interest in mental and emotional wellbeing. The major area of interest to me and my work is how to effectively manage the mind. For the most part, if you do not manage your mind; it will manage you and you may not like the way it does that!

The brain-mind combo has nothing other than memory and sensory awareness at its disposal when it comes to managing the mind. If presented with a situation it looks for similar events in memory and assesses the outcome of previously applied strategies, it worked then, it most likely will work now, so it may use that. However, if it did not work, then a new, the more novel approach may be sought, this could be something totally new or a derivation of previous strategies. 

If we take anxiety as an example. Anxiety disorders have a tendency to seek avoidance as a means of assuaging unwanted anxiety. So, what may start as a simple avoidance of some people or places, could end up as agoraphobia, where the only place a person feels relatively safe, is in their own home. As the condition develops further, it often becomes more probably, that even that safety is impaired and a constant feeling of fear is the norm. 

When it comes to memory improvement, mind management and managing conditions like anxiety, stress, depression, or confidence (among many other life-limiting conditions); hypnosis has an excellent record for helping people to overcome life's challenges; why not try it?

My aim here is to highlight the way hypnosis can help many people, whose condition is not deemed worthy of such medical intervention. Essentially helping ordinary people; live a more ordinary life! To find out more, why not make an appointment for a Free Consultation - here

The Research:  

Confirming earlier computational models, researchers at the University of California San Diego and UC San Diego School of Medicine, with colleagues in Arizona and Louisiana, report that episodic memories are encoded in the hippocampus of the human brain by distinct, sparse sets of neurons.

The findings are published in the January 15 issue of PNAS Online Early Edition.

Episodic memories are recollections of past events that occurred at a particular time and place, a sort of mental time travel to recall, for example, a past birthday party or conversation with a friend. Encoding of episodic memories occurs in the hippocampus -- a pair of small, seahorse-shaped regions located deep within the central portion of the brain -- but the precise mechanism and numbers of neurons involved have been unclear.

"Scientists are interested in these issues not only because of their implications for models of memory but also for health-related reasons," said first author John Wixted, PhD, Distinguished Professor in the Department of Psychology at UC San Diego. "For example, degeneration in this region of the brain is responsible for memory loss in the early stages of Alzheimer's disease." Wixted, with Larry Squire, PhD, Distinguished Professor of Psychiatry, Neurosciences and Psychology in UC San Diego School of Medicine, and colleagues studied brain function in 20 epileptic patients undergoing intracranial monitoring for clinical purposes.

Specifically, they recorded single-neuron activity as study participants read a continuous stream of words, some of which were repeated. Participants were asked to indicate whether the words were "new" or "old" if they recalled seeing the word earlier. Strong neural activity in the hippocampus associated with repeated words, but not novel words, was deemed evidence of activity related to episodic memory.

The scientists found that individual episodic memories are encoded and represented by the strong activity of small (fewer than 2.5 per cent) and usually non-overlapping sets of hippocampal neurons, a finding that perhaps helps explain why past research efforts have struggled to detect the process. At the same time, they noted that the firing rates or activity of remaining hippocampal neurons (approximately 97.5 per cent) were suppressed -- a phenomenon called neural sharpening. These findings are significant because they confirm what scientists have long believed to be true but for which direct evidence had been lacking.

The researchers also looked for related activity in the amygdala, a nearby brain region associated with emotion and emotional memory. Models do not predict episodic memories are encoded in the amygdala by sparse sets of neurons as they are in the hippocampus, and, indeed, the scientists found no such activity there.

"If treatments and preventions are to be developed for memory problems, and for diseases that affect memory," said Squire, "it will be important to know how the brain accomplishes learning and memory: What brain structures are important for memory and what jobs do they do? In our study, we found what could have been easily missed were it not for theoretical models of memory that had been developed earlier."

Co-authors include Stephen D. Goldinger, Arizona State University; Joel R. Kuhn, UC San Diego; Megan H. Papesh, Louisiana State University; Kris A. Smith, David M. Treiman and Peter N. Steinmetz, Barrow Neurological Institute.

Story Source:

Materials provided by University of California - San Diego. Originally written by Scott LaFee. Note: Content may be edited for style and length.

Journal Reference:

  1. John T. Wixted, Stephen D. Goldinger, Larry R. Squire, Joel R. Kuhn, Megan H. Papesh, Kris A. Smith, David M. Treiman, Peter N. Steinmetz. Coding of episodic memory in the human hippocampusProceedings of the National Academy of Sciences, 2018; 201716443 DOI: 10.1073/pnas.1716443115