Eating fish may reduce risk of stroke

By Gregory Kellett, a cognitive neuroscience researcher at SFSU and UCSF, and science writer for Lumos Labs.

Eating lots of fish, the ultimate brain food, was recently associated with reduced risk of stroke.

A study conducted by Jyrki Virtanen and his crew at the University of Kuopio in Finland found that people who ate more fish tended to have fewer strokes. Virtanen looked at a population of 2,313 participants over the age of 65 who had their brains scanned (via MRI) twice, with a 5-year lapse between scans. After analyzing answers the participants gave to diet-related questionnaires the researchers found that:

• Those eating fish 3 or more times a week had fewer sub-clinical infarcts or “mini-strokes” than those eating fish less than once a month.
• Consuming more fish was associated with more intact brain white matter.
• Fried fish is not so healthy, and seemed to negate the above benefits.

As seen in other research studying healthy brain food, omega-3 fatty acids, which are present in most fish oils, seem to be a key contributor to lowering the risk of stroke.

Reference: Virtanen, J. K., Siscovick, D. S., Longstreth, W. T., Kuller, L. H., & Mozaffarian, D. (2008). Fish consumption and risk of subclinical brain abnormalities on MRI in older adults. Neurology, 71(6), 439-446.

Brain Hydration

By Gregory Kellett, a cognitive neuroscience researcher at SFSU and UCSF, and science writer for Lumos Labs.

Your brain is made up of 60% water and many of us may not be drinking enough of the clear wet stuff to keep our thinking “juicy.”

Not drinking enough water has detrimental effects on our brains. When your body lacks water, brain cells and other neurons shrink and biochemical processes involved in cellular communication slow. A drop of as little as 1 to 2% of fluid levels can result in slower processing speeds, impaired short-term memory, tweaked visual tracking and deficits in attention.

With proper hydration however, neurons work best and are capable of reacting faster.

What constitutes proper hydration is controversial. Some say that it is important to imbibe 8 tall glasses of water daily, while others claim that one should only drink when thirsty.

In fact, there is no one golden rule to staying well hydrated. The amount of water each of us needs varies from person to person as it depends on each individual’s physiology and lifestyle activities like diet and exercise.

Experiment and see what feels good. In today’s world of infinite distractions however, it is best not to leave hydration to your sense of thirst alone. It is also important to note that your ability to notice thirst typically diminishes with age.

Also of note:

• Sweating from exercise or high temperatures can result in more than 3 liters an hour of fluid loss.
• The maximum amount of water the body is capable of absorbing is 1 liter an hour or 330 milliliters every 20 min (the ideal amount to drink under high sweat conditions).
• Although good for energy, foods high in protein and sugar increase the body’s need for water.

Warning!

Drinking too much water is very dangerous! Over-hydration causes a sodium imbalance that can be fatal. It is common for marathon runners to be hospitalized because of overzealous hydration during the race.

Approach fluid consumption with moderation.

References:

Armstrong, L. E., & Epstein, Y. (1999). Fluid-electrolyte balance during labor and exercise: concepts and misconceptions. International Journal of Sport Nutrition, 9(1), 1-12.

Kleiner, S. M. (1999). Water: an essential but overlooked nutrient. Journal of the American Dietetic Association, 99(2), 200-6.

Lang, F., Busch, G. L., Ritter, M., Völkl, H., Waldegger, S., Gulbins, E., et al. (1998). Functional significance of cell volume regulatory mechanisms. Physiological Reviews, 78(1), 247-306.

Lieberman, H. R. (2007). Hydration and cognition: a critical review and recommendations for future research. Journal of the American College of Nutrition, 26(5 Suppl), 555S-561S.

Maughan, R. J., Shirreffs, S. M., & Watson, P. (2007). Exercise, heat, hydration and the brain. Journal of the American College of Nutrition, 26(5 Suppl), 604S-612S.

Murray, R. (1998). Rehydration strategies–balancing substrate, fluid, and electrolyte provision. International Journal of Sports Medicine, 19 Suppl 2, S133-5.

Suhr, J. A., Hall, J., Patterson, S. M., & Niinistö, R. T. (2004). The relation of hydration status to cognitive performance in healthy older adults. International Journal of Psychophysiology: Official Journal of the International Organization of Psychophysiology, 53(2), 121-5.

Working memory training changes the brain

By Gregory Kellett, a cognitive neuroscience researcher at SFSU and science writer for Lumos Labs .

It seems that working memory training may work by physically altering the brain. Stockholm Brain Institute researchers put healthy people through working memory exercises for 35 minutes per day over a period of 5 weeks. Changes in dopamine receptor density were measured with positron emission tomography (PET) before and after the training.

Following working memory training, they found:

• An increase in the density of dopamine receptors.
• An improvement in working memory performance.

The neurotransmitter dopamine plays a central role in working memory. This research implies that improving working memory performance through several weeks of training might work by increasing the quantity of dopamine receptors in the brain.

References:
Buschkuehl, M., Jaeggi, S. M., Hutchison, S., Perrig-Chiello, P., Däpp, C., Müller, M., et al. (2008). Impact of working memory training on memory performance in old-old adults. Psychology and Aging, 23(4), 743-53.

Dahlin, E., Neely, A. S., Larsson, A., Bäckman, L., & Nyberg, L. (2008). Transfer of learning after updating training mediated by the striatum. Science (New York, N.Y.), 320(5882), 1510-2.

McNab, F., Varrone, A., Farde, L., Jucaite, A., Bystritsky, P., Forssberg, H., et al. (2009). Changes in cortical dopamine D1 receptor binding associated with cognitive training. Science (New York, N.Y.), 323(5915), 800-2.

Improving Memory with Magnets?

By Gregory Kellett, a cognitive neuroscience researcher at SFSU and UCSF, and science writer for Lumos Labs.

Scientists at the university of Sydney in Australia have recently claimed to be able to make people’s memory more accurate by reducing the occurrence of false memories… via magnets.

Although it is often possible to increase the precision of memory by paying better attention at the time of an event, little till now has been able to help improve remembrance after the fact.

The experimenters used electro-magnetic pulses via a technique called transcranial magnetic stimulation to decrease brain activity in such a way as to mimic the minds of people with anterior temporal lobe dementia and autism.  The logic behind this being that one of the common characteristics of these conditions is a more literal memory with greater accuracy for details.

Participants were given a list of words to memorize and then either actual magnetic brain manipulation, a sham manipulation or no treatment at all.

Those who actually had their brains magnetically pulsed after seeing the list of words showed a 36% decrease in false memories, meaning thinking a word was initially presented when it was not, over those whose brains were left untouched.

Although this leaves us with more questions than answers, the authors point to a possible future application in the courtroom, where memories frequently get a little too creative.

Reference:

Gallate, J., Chi, R., Ellwood, S., & Snyder, A. (2009). Reducing false memories by magnetic pulse stimulation. Neuroscience Letters, 449(3), 151-154. doi: 10.1016/j.neulet.2008.11.021.

Staying Sharp by Keeping Fit

By Gregory Kellett, a cognitive neuroscience researcher at SFSU and science writer for Lumos Labs.

It turns out there may be a link between cardiovascular fitness and the size of one’s hippocampus, a portion of the brain important for the formation of new memories.

Researchers from the University of Illinois and the University of Pittsburgh, looked at the cardiovascular fitness of 165 adults between the ages of 59 and 81. They also measured (via MRI) the size of each participant’s hippocampus and tested for spatial reasoning abilities.

What they found:

• Elderly adults who are physically fit tend to have larger hippocampi than those who are less fit.
• Having a larger hippocampus is correlated with better performance on spatial memory tasks.

Exercise has been linked to hippocampus size and spatial memory in rodents, but this is the first study to demonstrate a similar relationship in humans.

This is good news because although variable between individuals, it is well established that the hippocampus typically shrinks with age and that this shrinkage is associated with subtle but definite declines in memory and spatial orientation.

References:

Erickson, K. I., Prakash, R. S., Voss, M. W., Chaddock, L., Hu, L., Morris, K. S., et al. (2009). Aerobic fitness is associated with hippocampal volume in elderly humans. Hippocampus.

Kitabatake, Y., Sailor, K. A., Ming, G., & Song, H. (2007). Adult neurogenesis and hippocampal memory function: new cells, more plasticity, new memories? Neurosurgery Clinics of North America, 18(1), 105-13, x.

Work your Memory with the New Familiar Faces Game

You know those awkward moments when you’re supposed to know someone’s name but don’t… or where you have to ask someone to repeat themselves because you weren’t paying attention?

Well Lumos Labs has devised a new brain game to help you avoid those embarrassing situations. Its called Familiar Faces, and as the title implies, it involves remembering people’s faces, along with their names and food orders. Big tips and job promotions are the goal, and those are achieved by improving your service with practice.

Keeping in mind who ordered what will exercise both your working memory and attention, while possibly helping to make your social life a tad more comfortable. Check it out, and as always, feel free to give us your feedback.

Trying too hard to focus

By Gregory Kellett, a cognitive neuroscience researcher at SFSU and science writer for Lumos Labs .

A new study indicates that focusing too much might actually diminish your ability to pay attention. The researchers, based out of Carnegie Mellon University, used a phenomenon called the attentional blink as the center of their investigation.

An attentional blink is a deficit in visual attention which often occurs 200-500 milliseconds after the first of two visual items are presented during an experiment. The study looked at the ability of participants to detect that second visual item in the presence of visual distractions (moving grey dots).

Surprisingly, the distractors enhanced the ability of people to detect items often obscured by attentional blinks.

The authors hypothesize that the attentional blink phenomenon is due to an overexertion of control happening when target detection and memory consolidation overlap.

They surmise that the adding of distractors dissipates this overexertion of control, thereby enhancing performance.

So the next time you’re playing Speed Match you may want to try day dreaming a bit…it just might improve your score.

References:
Taatgen, N. A., Juvina, I., Schipper, M., Borst, J. P., & Martens, S. (n.d.). Too much control can hurt: A threaded cognition model of the attentional blink. Cognitive Psychology, In Press, Corrected Proof.

Salvucci, D. D., & Taatgen, N. A. (2008). Threaded cognition: An integrated theory of concurrent multitasking. Psychological
Review, 115(1), 101–130.

Less Food=More Memory?

By Gregory Kellett, a cognitive neuroscience researcher at SFSU and science writer for Lumos Labs .

Data collected by Agnes Flöel and her crew at the University of Munster in Germany seems to give yet another reason to resist that second helping of chocolate cake.

The research compared short-term memory performance of overweight individuals who reduced their caloric intake by 30% over 3 months with individuals who maintained their regular diet over the same 3 months.

Results:

• After 3 months, those on the decreased calorie diet improved by 20% on short-term memory tests of word recall.
• Participants who did not change their caloric intake showed no improvements.

The study coincides with multiple other studies demonstrating improved brain plasticity in animals fed calorie restricted diets. Some possible mechanisms at work include:

• The modified action of neurotransmitters
• The stimulation of neurogenesis (production of neurons)
• Increases in cell metabolism

However, in the above study, there may be other factors at work. As all the participants were overweight to begin with, the improvements could simply be due to an increase in overall health (IE blood flow, increased oxygen etc). Studies “starving” healthy individuals seem to be called for in order to eliminate this possibility.

References:
Caloric restriction improves memory in elderly humans. (2009, January 26). . Retrieved January 27, 2009, from http://www.pnas.org/content/early/2009/01/26/0808587106.

Fontán-Lozano, A., Sáez-Cassanelli, J. L., Inda, M. C., de los Santos-Arteaga, M., Sierra-Domínguez, S. A., López-Lluch, G., et al. (2007). Caloric restriction increases learning consolidation and facilitates synaptic plasticity through mechanisms dependent on NR2B subunits of the NMDA receptor. The Journal of Neuroscience: The Official Journal of the Society for Neuroscience, 27(38), 10185-95. doi: 10.1523/JNEUROSCI.2757-07.2007.

Stranahan, A., & Mattson, M. (2008). Impact of Energy Intake and Expenditure on Neuronal Plasticity. Neuromolecular Medicine.