Going Left (or right, depending on how you think of it)

 FYI, this is not a political post. It’s about which hand I use to color and write. It’s about going ambidextrous and seeing what my brain does with that.

For Christmas 2015, I was given one of those “adult” coloring books (the “adult’ part seems silly; just admit it, people like to color, and not just kids – so go ahead, bust out those old princess and TMNT coloring books and have at it!). I found the idea of taking up coloring quite lovely. After coloring two pages and realizing what a time suck they were, I had an idea to make it a little more of a challenge.

When I was a child, I did not discriminate between using my right and left hand (or so my parents told me) and wrote and colored with both hands. It wasn’t until I learned that using the right hand was traditionally considered the “right” way that I consciously began to favor the right hand. (You see, I was never one to want to be a rebel. I became one, but that was out of necessity. Justice can not always be had without putting in some effort.)

Anyway, I remembered that and thought this coloring book to be an opportunity. When I was a child, I colored before I wrote, so it made sense to start with coloring.

At first, all I wanted to do was become ambidextrous again. I was a little late in realizing that I should be somehow recording my progress. I also wondered what this might do to my brain. Specifically, I wanted to know if it would affect the way I thought and where I thought it, how it might affect my the lateralization of my brain.

Before I realized I wanted to turn it into a more meaningful observation, I was just coloring mindlessly (or perhaps mindfully, as the coloring book advertises), aside from the challenge of making my left hand stronger and more precise and choosing colors. Then, I tried writing and began recording times.

Instead of wandering through this idea, I decided to do some research and prepare a better self-study. I have stopped coloring/writing with my left hand for over a month. I will not resume until I have the background and a more focused approach.

About Dominant Hands

Most people are right handed (90%). [1] This is a genetic trait. As young children, our handedness is usually ambiguous and preference begins later but when is up for debate, although the preferred hand may be able to be foretold at 6 months of age. [1] The left hemisphere is known to control the right side of the body and is also the hemisphere were the language center is (87 – 96%). [1] Most left-handed people have their language center in the left hemisphere as well, with a small minority having bilaterally distributed language areas, as confirmed by studies done with functional transcranial sonography, TMS, and fMRI. Righthanders tend to be predominantly so; whereas, left-handed people discriminate less. It is usual that people preferred hand is also their most capable hand, but occasionally it is not. [1]

“Research has revealed that right handers display more activation in the right hemisphere when using the left hand, than in the left hemisphere when using the right hand.” [1]

Consequences of Switching Hands

A solid amount of research has been done on the impact of innate handedness and left-handed people switching to being right-handed, but less the other way around. There is at least one article that warns that becoming ambidextrous is harmful (at least as children) and commenters that strongly disagree; although I did find some of his research, I did not find those that validated his claims. Nonetheless, I will document some of the primary sources I could find that we have for hand-switching in case it illuminates useful information. Additionally, I will pay attention and see if I notice some of the symptoms of these claims.

Using fMRI, one study found this:

“Subjects performed the tasks using both the preferred and non-preferred hand. In right-handers, there was a general predominance of left-hemisphere activation relative to right hemisphere activation. In lefthanders this pattern was reversed. The switched subjects showed no such volumetric asymmetry. […] The switched individuals share features of both lefthanders and right-handers regarding their motor control architectures.” [2]

An additional study using fMRI discovered that righthanders have stronger asymmetry in their left hemisphere than lefthanders. [3] Further evidence was offered using PET scans. [4]

Via EEG, it appears that goal-directed activities are activated in the left hemisphere for both left and righthanders. [6] It is suggested that “handedness [is] strongly linked to an action-observation network in the parietal lobe.” [7]

Additionally, it was found to be psychologically unhealthy among older people when they unsuccessfully attempted to switch from being left-handed to right-handed. [5]

At this point, the information is more exciting than worrisome for me.

Split-brain Info

I have been fascinated by split-brain research for some time now and would like to see if some of that information can shed light on handedness, what does or may occur when switching hands, and the continuation of understanding lateralization in the brain in relation to handedness. I will do a run through of some of the things that we know about our hemispheres in relation to split-brain people.

When one refers to a split-brain, they are referring to a person who has had a callosotomy, where the corpus callosum is cut in patients who suffered from extreme seizures to interrupt its potential spread to other parts of the brain. From research on the patients who had had it done as well as research on other animals (mostly cats and monkeys), we learned more about the hemispheres of the brain, their functions and how we interpret and interact with our surroundings.

Over the years, researchers have discovered that the left side of the brain specializes in speech, while much of the visuospatial processing is done in the right hemisphere. [8] [9] This does not always extend to written language, however. “[…] spoken and written language output can be controlled by independent hemispheres.” [8]

“Despite hemispheric differences in the performance of these [visual] tasks, the two hemispheres are equally able to perform many visual tasks that lack a spatial component.” [8]

When it comes to calculations, the left side has an easier time forming exact answers, whereas the right side is better at approximating. [10]

When it comes to numbers, the left hemisphere was more accurate than the right with number words, but both hemispheres where able to deal with numerical representations regardless of coding. There was also a distance effect for both. [11]

“The results confirm that object-based attention is lateralized to the RH [right hemisphere]. They also suggest that subcortical interhemispheric competition may occur and be dominated by the RH.” [12]

The hemispheres appear to be specialized, but generally can use one another for things that are more difficult. Higher lateralization has appeared in young adults vs aging adults. Because the brain may access the other for more difficult tasks, increasing overall performance, it is thought that it may be that in older age, both hemispheres are needed as performance in each hemisphere is reduced. [8]

When delving into self-recognition, both sides of the brain appear to be able to self-recognize but this is dominant in the right hemisphere. Other types of research, out side of split-brain patients, supports this as well. [13]

“The evidence provides support for a right-dominated, but largely bilaterally distributed model for self-face processing. Four areas are consistently activated: the left fusiform gyrus, bilateral middle and inferior frontal gyri, and right precuneus. The evidence is interpreted in light of a developing model of self-face recognition as part of a larger social cognitive stream of processing.” [13] I don’t know what all those words mean yet, but, because I want to learn more of the specifics of the mind and how it works, they’re on the agenda as I move forward.

“Research with split-brain patients quickly established that each half brain is specialized for certain functions and is capable of processing stimuli without the obvious help or awareness of the opposite half brain” [8]. Although each side has specializations, the question of if each side of the brain have a sense of self is a live question. The jury is still out.

It seems that although speech may be the province of the left hemisphere, written language affects the right hemisphere for a left handed split brain patient. [8]

“The left hemisphere’s dominance for language is complemented by the right hemisphere’s specialization for visuospatial processing.” [8]

Due to apparent plasticity between the two hemispheres when it comes to visual tasks [8], I wonder if, by using my left hand, it will activate my right hemisphere for written language.

It has been speculated by some, based on split-brain data, that the two sides of the brain function as apologist (left) and revolutionary (right) and that the apologist invents justifications for current beliefs and the right is able to change their mind. I wonder, if true, if my ways of thinking could be influenced merely by using my left hand and altering the way my brain has to work to accommodate it.

Personal Exploration

Although, being a person with a whole brain (as far as I know), leads me to believe that my hemispheres more-or-less share duties, with each side having some specialization, it is likely that in using the left hand, something may be activated or changed in the right side of my brain. Whether this will result in something good or bad, subtle or otherwise, it would nonetheless be interesting to know. As a testament to neural plasticity, if nothing else.

I would like to see, in my own brain, some of the differences that might exist while I try to use my left hand, after having been right-handed for the majority of my life (and, genetically, may be right-handed). Ideally, I would be able to utilize fMRI and PET technologies to view my brain before and after (during would be cool too). As those are expensive technologies and I am but a lower-income citizen scientist, I will be limited to my own observations and the electrical signals that can be recorded using an EEG. To do this, I will have to research and understand EEG technology to use it to best effect. I may find that it is inappropriate for the task and have to figure out an alternative way to explore my questions. Regardless, it is a start and I’ll be better equipped for future study in other subjects.

Even if I don’t find the answer to my questions, I suspect I will at least learn to use my left hand for writing and coloring and perhaps drawing. The ways in which this will serve me, I have no idea.

The journey begins.

 

Sources

  1. Hand preference, performance abilities, and hand selection in children. Sara M. Scharoun and Pamela J. Bryden
  2. Switching handedness: fMRI study of hand motor control in right-handers, left-handers and converted left-handers. Grabowska A, Gut M, Binder M, Forsberg L, Rymarczyk K, Urbanik A.
  3. Cerebral asymmetry for language: Comparing production with comprehension. Isabelle S. Häberling, Anita Steinemann, Michael C. Corballis.
  4. Long-term consequences of switching handedness: a positron emission tomography study on handwriting in “converted” left-handers. Siebner HR, Limmer C, Peinemann A, Drzezga A, Bloem BR, Schwaiger M, Conrad B.
  5. The effects of hand preference side and hand preference switch history on measures of psychological and physical well-being and cognitive performance in a sample of older adult right-and left-handers. Porac C1, Searleman A.
  6. Cognitive control of response inhibition and switching: hemispheric lateralization and hand preference. Serrien DJ, Sovijärvi-Spapé MM.
  7. Cerebellar asymmetry, cortical asymmetry and handedness: Two independent networksIsabelle S Häberling, Michael C Corballis.
  8. The split-brain: Rooting consciousness in biology. Michael S. Gazzaniga
  9. The calculating hemispheres: studies of a split-brain patient. Funnell MG, Colvin MK, Gazzaniga MS.
  10. Numerical processing in the two hemispheres: studies of a split-brain patient. Colvin MK1, Funnell MG, Gazzaniga MS.
  11. Covert orienting in the split brain: Right hemisphere specialization for object-based attention. Kingstone A.
  12. The neural correlates of visual self-recognition. Christel Devue, Serge Brédart.
Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s