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.

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.

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.

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.

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.

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.

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.

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.

Recent findings have linked exercising regularly with increased cerebral blood flow and a greater number of blood vessels in the brain.

While it has been shown in the past that aerobic exercise might reduce cognitive decline, this study demonstrated a possible explanation: changes in the brain’s blood vessels and blood flow.

The researchers recruited 12 healthy adults, age 60 to 76. Six of the adults participated in aerobic exercise for three or more hours per week over 10 years, and six exercised less than one hour per week. All of the volunteers underwent MRI to determine cerebral blood flow and MR angiography to depict blood vessels in the brain.

Compared to the inactive group, the people who exercised regularly had more small blood vessels carrying blood through the brain, and the blood flowed in a more normal pattern.

Ever wonder about the workings of your nervous system?  As mentioned in our previous post on cognition, the nervous system is responsible for integrating and processing information about your surroundings while directing action towards the achievement of goals; whether this be eating a tuna sandwich, serenading a lover or getting out of the way of a speeding bus. Physically, it is made up of your brain, spinal cord and peripheral nerves.

Let’s look at the structural components of this biological orchestra.

Neurons and Glia
The basic functional units of the nervous system include neurons (cells who’s primary job is to communicate) and glia (cells which support neurons and their communication).

The average brain has about 100 billion neurons and about 9 times as many glia.

Neurons (with the help of glia) connect and coordinate senses such as sight, hearing, smell, touch and taste with the activity of your muscles and organs. They are either taking information in for integration, communicating with other neurons for information processing, or sending information out to generate action.

Glial cells (of which there are multiple types) do a variety of tasks to support the functioning of neurons, including removing waste, providing nutritional and structural support and facilitating connections. Some glia have also been shown to communicate with neurons, as well as each other, in order to help coordinate neuronal activity.

Synapses and Neurotransmitters
Synapses are the actual locations at which neurons communicate with each other, and a typical neuron has about 10,000 of them.

Neurons communicate at synapses through the use of neurotransmitters. Neurotransmitters are chemicals sent between neurons as well as the muscles and organs they work with. They attach to receptors on receiving cells, translating into one of three basic types of messages:

•    Excitatory- Encouraging connected neurons and other related cells to “pass it on” or activate; perhaps prompting you to swat at that fly after being buzzed by the umpteenth time or dilate your pupils when the lights go out.

•    Inhibitory- Suggesting that the receiving cell not continue passing on the signal or take action. This could be involved in the shutting down of appetite in response to the non-acquired taste of anchovies or the ability to ignore the radio in your car while figuring out how to get un-lost.

• Adaptive- Instructing a neuron to change something in its structure or the way it functions. This is the basis of plasticity where neurons may reduce or increase the number of connections, move them around and or adjust their sensitivity; all of which are part of the learning process.

Neural Networks

Neurons which collaborate on a specific physiological function, such as hearing high pitches, moving your pinky or remembering to take the trash out, are considered to be part of a shared neural network. Typically these functionally related neurons will use only one or two of the over 100 different types of neurotransmitters available. Neurotransmitters, however, can and often are associated with several types of neural networks.

Serotonin is an example of a neurotransmitter involved with the regulation of multiple systems including mood, appetite, temperature, pain sensation and sleep.

Dopamine is the neurotransmitter of choice for neural networks dealing with reward, such as the feeling you get after winning an egg toss or eating a delicious meal. It is however also used by circuits involving memory and attention.

Complexity
As much as we do know about how our nervous systems work, there is still much more to be discovered. One of the many areas where little is known involves how different neural networks, responsible for such diverse tasks as detecting movement, recognizing objects and generating action, can communicate between themselves. The mechanisms involved in coordinating the information from different specialized neural systems into a seamless experience of say, catching a ball, is still a mystery.  This is referred to as the binding problem, and although there are plenty of theories, there are no clear answers as of yet.

As you can see, the interactions between our neurons, neurotransmitters and constantly shifting surroundings are complex…..especially when they are trying to grasp the complexity of interactions between neurons, neurotransmitters and constantly shifting surroundings;)