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;)

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.

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

Long-term and Working Memory – You Are What You Remember

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

Memories are vital to our ability to function on even the most basic of levels. Our respective “realities” are in fact a large part due to the constantly shifting kaleidoscope of our remembrances. Here we will touch briefly on the difference between short-term/working memory and long-term memory as well as how the two filter and add meaning to our worlds.

What if we could remember everything we experienced? As enticing as it sounds, our finite brains would quickly find themselves overwhelmed with the random details of yesterday’s weather forecast alongside the nutritional information off of last month’s box of raisin bran.

Thankfully, the vast majority of our memories are fleeting mental wisps lasting only seconds to minutes. These temporary impressions make up what is called short-term or working memory.

Working memory can be thought of as a staging area where the mind takes meaning from such items as:

• Specific immediate memories of very recent sensory input (IE the sour smell of expired milk).
• The temporary recollection of details from long-term memories (IE what happened the last time you drank sour milk).
• Conclusions and ideas made in the past (Sour milk is bad).

Notice how working memory can temporarily pull details from long-term memory for short-term use. Although constantly changing and ephemeral itself, working memory is vital to our ability to make decisions and take action over time (such as our pouring that sour milk down the drain). For a brilliant and more in-depth description of working memory read Elizabeth Buchen’s “Working Memory: What it is and how it works”.

When an experience or piece of information sticks and doesn’t evaporate with short-term memory, it is said to have entered into the realm of long-term memory. This journey is called consolidation and takes place after prolonged exposure to a piece of information or experience. The longer the exposure, the better the consolidation, the more robust the related memories will be.

Long-term memories can store much larger quantities of information than working memory and for much longer periods of time (often as much as a lifetime). These resilient long-term recollections are made up of both consciously learned facts, such as “Madrid is the capital of Spain” and subconsciously learned knowledge, such as the ability to balance and ride a bike.

We derive meaning and the ability to act via the synergistic relationship between long-term and working memory. Working memory combines elements from our long-term stores with immediate sensory information in order to generate ideas and plans of action. For example, remembering that the taste of peanut butter is pleasant as we toast toast, might just have us use our memorized skill of unscrewing a jar in order to manifest the pleasurable experience of peanut butter on toast. Which is just one more potentially delicious result of a fit and active mind.

Brain Performance Index – What is BPI?

Your Brain Performance Index (BPI) is how you measure and track your cognitive performance, and compare your ability in one area to another. All active Lumosity users have a BPI. You can check yours in the My History section, or if you’re not already a member you can sign-up and get your BPI by playing the brain training games.

An increase in BPI indicates improvement. An increase of more than 200 points represents a substantial improvement of at least 1 standard deviation. Remember that BPI is a way to track your own personal progress – it is not intended as a way to compare yourself to other people.

How is BPI calculated?

The BPI scales are based on an analysis and ranking of over 7,200,000 real game results. We used these game results to create a distribution of scores for each activity so we know how an individual score stacks up to all others. We then evaluate your game scores and use a proprietary algorithm to derive your BPI. Each time you play, we update your BPI to accurately reflect your current brain performance.

How is overall BPI calculated?

Your Overall BPI is your average BPI across each of the four cognitive areas: attention, memory, processing speed and cognitive control. This number provides a concise measure of your overall brain performance. If you are weak in one area, it will bring down your overall score, so it’s a good idea to focus on the games where you scores are lowest.

Can I compare my BPI in one area to another?

Yes. The BPI converts scores in very different activities to the same scale based on average scores across all users. For example, a BPI of 400 in Birdwatching is equivalent to a BPI of 400 in Word Bubbles.

Intelligence and your perfect sense of pace

Think you’ve got rhythm? Well, now there’s a reason beyond musicianship and dance-floor bravado to claim an accurate sense of the beat:

Good rhythm is correlated with general intelligence.

Fredrik Ullen and a team of researchers in Sweden found that people who most accurately tap out a beat also do the best on intelligence tests. They suggest that the brain’s sense of timing might underlie higher intellectual functions. The paper was published this week in the Journal of Neuroscience.

From the press release on physorg:

“It’s interesting as the task didn’t involve any kind of problem solving,” says Fredrik Ullén at Karolinska Institutet, who led the study with Guy Madison at Umeå University. “Irregularity of timing probably arises at a more fundamental biological level owing to a kind of noise in brain activity.”

According to Fredrik Ullén, the results suggest that the rhythmic accuracy in brain activity observable when the person just maintains a steady beat is also important to the problem-solving capacity that is measured with intelligence tests.

“We know that accuracy at millisecond level in neuronal activity is critical to information processing and learning processes,” he says.

They also found differences in the anatomy of the prefrontal cortex – a part of your brain involved in many complex cognitive tasks. The subjects with good rhythmic accuracy and intelligence had more white matter volume in the prefrontal cortex.

As is common with an interesting result, this study prompts many new questions:

Does this correlation arise out of a difference in noisiness at the neuronal level, as the release suggests? Or do keeping time and intelligence both arise from higher level cognitive processes, like attention and working memory?

Can intelligence be altered by improving rhythm? Is Ringo Starr actually the smartest in the band?

More white matter in the prefrontal cortex implies more myelin, which aids in fast and reliable communication between neurons. Does the additional myelination improve communication between neurons to the point that rhythm and intelligence are both enhanced?

Brain performance enhancer: Caffeine

Chris Chatham at Developing Intelligence published a great guide to getting the most cognitive benefit out of caffeine. We’ve mentioned before that caffeine can improve memory and reaction time and that coffee might be protective against dementia. But we haven’t yet gotten into the implementation – what’s the best way to consume caffeine for sustained cognitive performance? Chris outlines the approach indicated by empirical research in Caffeine: A User’s Guide to Getting Optimally Wired.

One of his stronger points is the value of small and frequent doses of caffeine rather than a venti chug to start the day. Caffeine reaches the brain quickly, and then your system begins to gradually remove it, so you may be best off having about a quarter-cup each hour over the course of the time you want to be alert.

Keep in mind that there are cardiovascular risks to too much caffeine use, and that it is an addictive drug. That said, Lumos Labs averages about 3 cups/day – close to the US average of 3.1/day – and we show no signs of slowing down.