Thursday, January 30, 2014

Mental Time Travel

Travis Suttle

Have you ever wondered how athletes pull things off like this?
That's a triple cork 1440, or three backflips and four spins simultaneously! To perform a trick like that, it takes a insane amount of athletic ability (and some big cojones), but most importantly, it involves training the brain using motor imagery.  Through motor imagery, humans can imagine actions and develop neural circuits for those actions without even performing the movement at all.  In some situations, motor imagery is used to imagine performing actions in the future, which is a form of mental time travel.

Through mental time travel, one can imagine a possible future event and prepare for it by determining an appropriate reaction to the situation.  So before that snowboarder even left the jump, he had likely practiced that trick over and over again in his head picturing the world spinning and turning upside down.


Mental time travel is a term coined by Dr. Thomas Suddendorf referring to a human's ability to mentally project themselves into the future or back into time. The definition of mental time travel is voluntary behavior that solves a problem that an organism may encounter in the future.  Mental time travel is usually based on the recollection of previous events (episodic memories) and increases the flexibility of the reaction next time the event or a similar event occurs.  Humans have an extraordinary ability to foresee events and plan accordingly, whereas other animals are simply reacting to stimuli, rather than predicting stimuli then planning actions.

Action sports athletes are not the only people who benefit in training this way.  Sports psychologists have been teaching visualization methods to improve athlete performances for years.  For example, Tiger Woods is known to be a master of visualization (seen herewhich has led him to go down as one of the most successful golfers of all time.  The video discusses the pre-shot routine that Tiger goes through where he "visualizes the golf shot using his hands, fingers, and body awareness" to come up with the correct technique to make the best shot. So Tiger isn't "just doing it" after all, and he certainly is keeping more secrets that the one his wife found out about (double pun).

Another exemplification of the mental time travel involves Air Force Colonel George Hall, a pilot who was shot down over Vietnam and captured as a POW.  He spent seven years in a North Vietnamese prison where he played golf in his mind everyday to pass time. He used motor imagery over and over to establish motor circuits and develop his swing.  After he was rescued and returned home, he decided to play his first game of golf in over seven years at the 1973 New Orleans PGA Open where he shot a 76 (a really good score)!

So how can we do this?  Researchers found that the neural network activated while performing a movement is also activated while imagining oneself performing that movement.  Surprisingly, imagery training in athletes, stroke patents, and musicians significantly increases the electromyography (EMG) activity of target muscles in comparison to resting EMG activity.  This means that imagining oneself performing an action is actually sending electrical signals to the desired muscles but the signals are not strong enough for the muscle to completely contract. In another study, imagined weight lifting with the forearm showed a linear increase of EMG amplitudes with increasing magnitudes in weight.  In other words, your brain is sending stronger signals when you imagine lifting heavier weights.  

The prefrontal cortex is thought to play a crucial role in motor imagery, as patients with left lateral prefrontal lesions were unable to imagine a motor task.  In general, the prefrontal cortex is believed to be involved in attention, cognition, and performing actions.  The corticopontino-cerebellar tract (which has connections to the prefrontal cortex) is important in coordination of movements and has been shown to establish and consolidate fine motor skills through reorganization in the sensory-motor system.  So now that we know the neural network proposed to be responsible for the learned responses through motor imagery during mental time travel, lets take a look at how the scientific community believed these neural networks were first established.

Evolution of Mental Time Travel
So how did we gain this capacity to time travel using our imagination?  For mental time travel to have evolved, it must have had an effect on survival or reproduction for natural selection to work on.  Dr. Thomas Suddendorf and his colleagues believe that mental time travel changes behavior in the present, which therefore may increase survival chances in the future.  For example, when preparing for a job interview, one might think of questions that an interviewer may ask, then formulate responses to them and simulate the situation in his or her imagination; this in turn, may increase one's chances of getting that job.  Now if getting the job is a life or death situation (or a situation that results in reproduction), this interview becomes an event that natural selection can act on.

Here's another example of a situation that our ancestors could've experienced.
Lets say you're an early hominid that was banned from your tribe and you're scavenging the forest alone.  All of a sudden, a sabertooth jumps out and chases you, but you manage to escape.  In the process of escaping, you accidentally cut yourself on a small rock. As you sit and ponder about the situation (mental time traveling) in your cave, you recall the sabertooth chasing you as well as cutting yourself on that darned rock (recalling episodic memories).  Thankfully, you have an extra large prefrontal cortex in comparison to other early hominids and therefore, you can picture yourself in the same situation with the sabertooth (mental time traveling), but this time you are wielding the sharp rock you cut yourself on and you attack the sabertooth (motor imagery).  After imagining the situation, you run out of your cave, grab the sharp rock, make a spear, and kill the sabertooth.  You then drag the sabertooth back to the village you were previously shunned from and all the ladies adore you for your bravery (increasing your evolutionary fitness)!

Potential Evidence
Okay enough story telling, let's get back to it!  Around 2 million years ago, the genus Homo emerged with an increased brain size, which possibly represents the time that language and mental time travel were born.  Tools and weapons made of stone are the earliest evidence of foresight - they were used repeatedly and transported in anticipation of future use. Great apes do throw objects, but they are not known to carry them around.  Carrying weapons for defensive use must have been strongly selected for as early humans were believed to be the prey of much larger animals.  This foresight may have allowed us to outcompete our ancestors and predators leading to their demise and our prosperity.  In further support, area 10 of the human prefrontal cortex is much larger than the prefrontal cortex of all of the other apes relative to the total brain volume (see the figure below).  Area 10 of the prefrontal cortex is the cortical area believed to be involved in higher cognitive functions such as planning of future actions.  This suggests that the increase in size of area 10 may have played a large role in hominid evolution as it allowed early hominids to plan for future situations.

Let's get a little philosophical to conclude this blog entry. If we are the only animals on earth which have such unique foresight, we alone may be driven to consciously guide the planet into the future.  Furthermore, we carry the responsibility of making decisions about the future and getting them right.  For example, what if we are in a situation where an asteroid is in course to collide with earth?  We are the only animals on earth with the capability to foresee the consequences and chose to act.  Hopefully this isn't the choice we make...

Lastly, in the words of Albert Einstein himself: "Imagination is more important than knowledge."  This quote especially applies when your imagination allows you to predict a situation and develop complex motor functions to respond to the situation.

Works Cited:

Goldman-Rakic, P. 1988. Topography of cognition: parallel distributed networks in primate association cortex. Annual Review of Neuroscience 11:137–56.

Johnson, S.H. 2000. Imagining the impossible: intact motor representations in hemiplegics. Neuroreport 11:729–732. 

Lotze, M., and U. Halsband. 2006. Motor imagery. Journal of Physiology Paris, 99:4-6.

Semendeferi, K., E. Armstrong, A. Schleicher, K. Zilles, and G.W. Van Hoesen. 2001. Prefrontal cortex in humans and apes: a comparative study of area 10. American Journal of Physical Anthropology 114:224-241.

Suddendorf, T., and M. Corballis. 2007. The evolution of foresight: what is mental time travel, and is it unique to humans?. Behavioral and Brain Sciences 30:299-313.

Zhang, H., L. Xu, S. Wang, B. Xie, J. Guo, et al. 2011. Behavioral improvements and brain functional alterations by motor imagery training. Brain Research 1407:38-46.

Zhang, H., Z. Long, R. Ge, L. Xu, Z. Jin, et al. 2014. Motor imagery learning modulates functional connectivity of multiple brain systems in resting state. PLOS One 9:e85489.

Images and Videos

1 comment:

  1. Good explanation! I read about a group of scientists who were able to prove that visualizing a shot over and over and was as effective a practicing mechanism as actually doing it.