Physical Exercise and Brain Blood Flow

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

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.

Your Nervous System at Work

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

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;)

Smoking and the Brain

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

A recent research review to be published in the journal Progress in Neuropsychopharmacology & Biological Psychiatry shows a link between cigarette smoking and adverse changes in the function and physiology of the brain. Summarizing the findings of dozens of experiments, the review indicates that:

• Strokes are more prevalent in smokers than non-smokers.
• Gray matter (made up of brain cells) shrinks in long-term smokers.
• Smoking is associated with less integrity in the white matter connecting brain hemispheres.
• Puffing tobacco can be bad for neurotransmitters.

There are a few factors clouding the picture however. These include the fact that alcohol consumption often accompanies cigarette smoking and has also been shown to have detrimental effects on the brain.

In addition there is the question of which comes first: brain abnormalities or smoking habits. It is possible that preexisting brain abnormalities increase the likelihood of smoking and addiction.  The author suggested more research in order to answer these questions, as well as to determine if these symptoms are reversible after quitting.

References:

Domino, E. (2008). Tobacco Smoking and MRI/MRS Brain Abnormalities Compared to Nonsmokers. Progress in Neuro-Psychopharmacology and Biological Psychiatry, In press.

Musicians, Creativity and Balanced Brain Use

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

Research just published in the journal Brain and Cognition suggests that musical training can lead to more creative thinking and more symmetrical brain activity. The investigators, based out of Vanderbilt University in Nashville Tennessee, ran two experiments both comparing 20 musicians (with a minimum of 8 years of musical experience) with 20 non-musicians.

The first looked at potential differences in creative abilities by asking participants to come up with as many novel uses of common household items as possible, followed by their completing a word association task.

The second study monitored brain blood flow via near infrared spectroscopy (NIRS) while participants again generated as many novel uses of everyday objects as possible.

The data indicated that:

• On average the musicians were able to generate about 13 more examples of how to use common objects than non-musicians.
• The musicians performed better on the word association task, producing an average of approximately 9 more correct responses than their non-musical counter parts.
• Overall, during the creative tasks, musicians showed more symmetrical brain blood flow between the hemispheres than the non-musicians.

Although it is always possible that creative people tend to be more drawn to the world of music than non-creative people, the authors suggest that the results might be due to the ability of certain aspects of music training, such as improvisation and song creation, to enhance cognitive and neural mechanisms of the creative process.

References:

Gibson, C., Folley, B. S., & Park, S. (2008). Enhanced divergent thinking and creativity in musicians: A behavioral and near-infrared spectroscopy study. Brain and Cognition.

What is Cognition?

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

What exactly is cognition and how does it work? Here we will attempt to outline and explain some of the basic concepts involved with the inner workings of your head.

Cognition literally means “to know”.  Knowledge can be thought of as memories formed from the manipulation and assimilation of raw input , perceived via our senses of sight, hearing, taste, touch and smell.

Using knowledge to direct and adapt action towards goals is the foundation of the cognitive process. Past experiences and trends inform our sense of what the future might hold and help us to act accordingly.

Take a yearning for pizza for example… Cognition encompasses everything from knowing/remembering what pizza is (and that you like it)…to realizing that you are hungry and making plans to have it delivered.

In order for our finite minds to make sense of the near infinite details of our surroundings however,  a large part of cognition involves the organization of our thoughts into associations or categories. These might range from “things one might find in a kitchen” to “people I think are cute”. Simple symbols such as the word “face” are used to group more complex learned associations such as those between noses, lips, eyes and smiles.

Although important, these “cognitive categories” are overlapping and not always clearly distinct…so keep this in mind as we break down the concept of cognition itself into some of its more widely recognized pieces.

The words perception, attention, memory and executive function are one way of divvying up the processes involved in how we think. All of the above will be involved throughout your journey towards satisfying that pizza craving. Let’s use some specific points to illustrate their role in the overall process of attaining such a dinner goal.

Perception, in this case, of the fact that you feel hungry and that there is no food in the fridge, is what gets the whole process moving. It involves seeing, hearing, feeling, tasting and or smelling your surroundings, allowing you to respond appropriately.

Memory plays the obvious role of storing the name of your favorite pizza parlor. It also enables you to dial the number given by the operator and give directions to your house. Some different components include short term/working memory, long-term memory and subconscious/implicit knowledge.

Executive Function enables the planning of logistics, such as timing the pizza delivery to coincide with the arrival of your scrabble buddies.  Improvising (guessing what toppings everyone will enjoy), problem solving (figuring how much to tip) and controlling impulses (not ruining your appetite by eating a whole bag of Doritos while waiting) also come into play here.

Attention processes kick in by having you shift your focus from reading the Sunday funnies to answering the door upon hearing that long awaited knock. They also help in multi-tasking a slice of pizza with figuring out how to nail that triple word score all while ignoring the heckling antics of your so called “friends”.

Again, although separated for the purposes of our discussion here, it is the interplay of all of these systems working simultaneously which makes up the process of cognition; allowing us to adapt to our surroundings and take action towards obtaining our goals.

Older People Learning Newer Tricks

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

Recent research coming out of Hamburg, Germany and published in the Journal of Neuroscience demonstrates that older brains still have the flexibility to literally grow. Researcher Janina Boyke and crew, split 50 people with an average age of 60 years into two groups. One half of the participants were trained in the fine art of juggling over the course of 3 months while the other half was not. Three MRI brain scans were taken: one before the juggling began, another after 3 months of juggling training and a yet a third after 3 months of no juggling.

The data revealed that:

• The juggling group showed significant increases in brain gray matter above the non-juggling controls. These increases took place in the hippocampus (responsible for memory formation), the nucleus accumbens (involved in reward systems) and various visual centers.

• Three months after the end of training none of the individuals from the juggling group could still juggle and the gray matter increases had declined back to baseline. (Can you say “Use it or lose it“)

The authors note the growth of the nucleus accumbens (involved in reward systems) to be of particular interest, suggesting that it may have been involved in “…turning reward information into motivated action”.

Surgical Gaming

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

Video game play seems to be related to better surgical skills according to research showcased at the recent Annual Convention of the American Psychological Association.

Iowa State University psychologist Douglas Gentile, PhD, ran an experiment looking at the video game experience of 33 budding surgeons and how this related to performance during surgical training.

The numbers showed that:

• Past video game play in excess of 3 hrs/wk correlated with 37% fewer errors and a 27% increase in speed (over non-video-game players) during training exercises.

• Video game skill (as measured by high scores) were a significant predictor of demonstrated surgical skills.

Although this doesn’t necessarily translate as cause and effect, it seems plausible that exercising fine motor control, visual attention processing, reaction time, hand-eye coordination and 2-dimensional depth perception might just improve one’s ability to wield a scalpel.

References:

Rosser, J. C., Lynch, P. J., Cuddihy, L., Gentile, D. A., Klonsky, J., & Merrell, R. (2007). The Impact of Video Games on Training Surgeons in the 21st Century. Arch Surg, 142(2), 181-186.

Dorval, M., & Pépin, M. (1986). Effect of playing a video game on a measure of spatial visualization. Perceptual and Motor Skills, 62(1), 159-62.

Intelligence training

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

A study conducted by Martin Buschkuehl and Susanne Jaeggi in John Jonides’ lab at the University of Michigan indicates that it is possible to improve on measures of fluid intelligence by training one’s working memory.

The concept of fluid intelligence (gF) as defined by its founder Raymond Cattell is “…the ability to perceive relationships independent of previous specific practice or instruction concerning those relationships.” Fluid intelligence contributes to abilities like learning and problem solving. It is distinct from its counterpart, crystallized intelligence (cF) which involves  “…abilities that have obviously been acquired, such as verbal and numerical ability, mechanical aptitude, social skills, and so on.”

Fluid intelligence tests usually entail completing visual patterns of some kind.  Performance on such tests typically declines after reaching a peak in early adulthood.  This study, however, offers evidence that it’s possible to improve fluid intelligence, at least temporarily.

The researchers used a computer-based working memory task called the “dual n-back” to simultaneously administer auditory and visual stimuli in sequence.  A response was required whenever one of the presented stimuli (visual or auditory) matched a previously presented stimulus n positions back in the sequence.  Four groups trained daily for either 8, 12, 17 or 19 days, with each group being matched by a control group that did not have training.  Pre and post tests of fluid intelligence were given to all groups.

What the study found:

• The working memory training significantly improved performance on the fluid intelligence tests.
• Fluid intelligence performance improved in proportion to the amount of training received.
• Working memory (as measured by digit span) also improved significantly.

The authors suggest that the above effects were due primarily to an increased ability to control attention.

References:

Cattell, R. B. (1971). Abilities: Their structure, growth, and action. New York: Houghton Mifflin.

Jaeggi, S., Buschkuehl, M., Jonides, J., Perrig, J. (2008). “Improving fluid intelligence with training on working memory.” PNAS- Proceedings of the National Academy of Sciences