Handedness, Brain Dominance and Autism?

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This is why I love the internet... I go looking for one thing and find something unexpected and wonderful...

Left Hand, Left Brain: The Plot Thickens - click!

It is a long article but a wonderful read if you're interested in brain dominance. I have been because I am left handed and neuroscience is still actively debating the issue of brain hemisphere dominance. This is some exciting, preliminary research that suggests the genetics that could possibly be linked to autism, among other things. Word of warning - this is not an 'AUTISM' article. This is a geneticist research as it applies to neuroscience. It just happens to have autism answer possibilites.

I found it exciting!

I am bookmarking your link for another time because i am too sleepy to read at the moment, but thought you might like the research here:

http://leftinthedark.org.uk/files#Split ... _Dominance

You will also see studies detailing on nutrition may have caused cerebral dominance over a period of thousands and thousands of years. There is an entire book on the subject named Left In The Dark which looks really interesting to me.

...with the added bonus of 'The Neuropsychiatry of Paranormal Experiences'. A 2 for 1 link. Both are right up my alley.

Thanks!

Havent read it yet but my aspie son is left handed.....

I'm an aspie and I'm left handed. I also feel the right sife of my brain tingle when I'm doing things, or thinking.

In the article I found it particularly interesting that the language centers were found in both hemispheres in 3% of the population. And that this is correlated with psychosis and schizophrenia. Might partially explain why schizophrenics hear voices and have disorganized thoughts, writings, and verbal interaction, at times.

I also found it interesting that 70 percent of left handers still have a dominant left hemisphere with the language center in that hemisphere, Only leaving about 30 percent of left handers with right hemispheric dominance.

The left hair swirl for left handers vs. the right hair swirl for right handers was also interesting. First time I had heard anyone suggest a possible relationship between handedness and homosexuality through the correlation of the left hair swirl and left handedness.

A very interesting article with new information I have not been exposed to. Thanks for providing the link.

You know, I couldn't help wondering about the schizophrenia... if it is a 'duel brain' issue, would splitting the corpus callosum, like they do in epilepsy, cure the condition?

I was reading this from my perspective and what I learned is that I am in 3% of the population. If the genetics play out as suggested, I am one highly improbable statistic. I am the culminative of every recessive trait in both sides of my family. This clarified how that was possible. If all recessive traits follow this pattern, imagine how many conditions they can decipher...

Glad you found it as interesting as I did.

The splitting of the corpus callosum was also found to produce two separate consciousnesses that were unaware of each other. My thought in schizophrenia and verbal centers in both hemispheres was that for some people the voice they are sure they hear may be the voice they partially hear in the other hemisphere.

In people with Autism research suggests that there are problems with communication between the hemispheres, I haven't seen studies, but I wouldn't be surprised if this is also the case for some with schizophrenia. It may also partially explain difficulty that some people with Autism and Schizophrenia have with emotions, because information about emotions may not be efficiently communicated between the hemispheres.

Additionally, I understand there may also be issues with the frontal lobes and communication with the back of the brain. My understanding here, is, this may also cause problems with frontal lobe communication and the emotional centers of the brain.

In wondering about what causes these differences in the development of the brain, I think of genetics, but I also think about hormonal influences during pregnancy and brain development.

Out of curiosity and if you wish to share, did you have a development delay in language when you were young. I was delayed until age four, had problems verbally communicating most of my life, and stuttered moderately through my teenage years. I saw the relationship there in the article you presented for left handers.

I use both, for different activities, but predominantly write with my right hand if you want to call chicken scratch writing. And another question, do you find organizing communication easier when typing or easier when speaking?

Finally how did you determine you were one of those three percent that have verbal centers in both hemispheres?

I'm left-handed, and I had an enormous receptive language delay, with a smaller initial expressive delay (and then a much longer delay in expressive communicative language, because I harnessed echolalia to respond to people at a time when I had no clue what language is, and therefore my speech was barely communicative if ever). But by far my biggest language issues remain receptive (I don't understand language unless I work hard at it, sometimes can't even do that, and at my best I still don't understand it nearly as well as I write it or as well as other people understand it). Oh and I never noticed this (possibly because I wasn't noticing the meaning of language in general?) but on tapes of myself as a child I had a fairly pronounced stutter.

I hope I didn't read those numbers incorrectly... I'm a lefthander that is extremely right brained. I'm in that small percentage of lefthanders that is actually right brained. This is the first research I've read that suggested it could possibly be otherwise. I'm fairly sure I'm not operating on two sides. But I am questioning many things now.

I did not have a speech delay as far as I know. My parents passed long ago and there is much I'll never know. From what I remember being told, I spoke ontime but developed an extensive vocabulary. I consider myself articulate - I did need to train large groups of people on self written material and write press releases and newspaper articles. Basically I'm excellent on paper but the live feed isn't anywhere near as eloquent. I am frequently misunderstood. Despite my big vocabulary I can never seem to find the proper words to express my feelings verbally. I'm guessing this suggests that my speech center is on the left.

I was actually searching for a different article when I found this one. The one I was looking for discusses handedness and brain dominance and the effect on lefthanders forced to use their right hand. It actually compliments this article well.

In Two Minds - click!

This one suggests that our right oriented society forces lefties to use their nondominant side often and actually increases the size and the effeciency of the corpus callosum. They also note the predominance of lefthanded aspies.

These two articles together have given me a new perspective. I've always been enthralled with the research into lefthandedness. I am extremely visual and very emotional. I have actually received a critique on a job performance review that I am 'too creative'. At times I very much agree. It is frustrating because don't think I could ever have adequate outlets for it. It's always on and I haven't found anyone yet that can grasp what I'm trying to deal with on a daily basis. I can't shut it off and I always feel like a failure because I can never bring my ideas to life in a satisfying way. I can write very well (not that posts display that very well...) just don't ask me to explain verbally. I've gotten through life okay... not great. I am now wondering if being a left hander, forced to exercise my left brain daily since childhood has made that possible and further hid my Aspiness.

If exercising the opposite side of your brain enhances a right brained lefty's communication, can it be employed as a therapy? If you are a righty - (natural right, not forced) - and you performed certain tasks always with your left hand daily, would it increase your emotional awareness?

The discussion about hormones, and the timing of brain development only raise more questions for me. If testosterone is an implicating factor in Asperger's and also influences recessive genes in brain formation influencing lateral brain dominance - how does that explain me? Females are not factored into this research.

In concert, these articles are putting the grey matter to work...

[edit - embarassing but I corrected two instances of right/left above... 43 years old and I still need to hold up my writing hand to know which side is left... ]

Last edited by draelynn on 03 Apr 2011, 12:09 pm, edited 1 time in total.

That's some cool stuff, food for thought. I'm much the same way, very good at expressing my thoughts in writing, but mediocre when I have to articulate. The dominant hand thing is what got me thinking though. I'm sort of right-handed. I seem to dimly remember being told by the teacher to pick up the pencil in my right hand. When I picked up my first BB gun at a tender age (here in Montana they start you on guns early) there were no coaches around, only my older brothers who didn't notice I set it on my left shoulder because that 'felt' right. Turns out the left is my dominant eye, something no one but shooters pay attention to. I'm wondering if eye dominance is a right/left brain thing too. Probably no research on it.

So to this day I write with my right hand, and that seems comfortable, but I shoot with my left and that still feels natural too. Other things I seem to be able to do fairly well with either. BTW I'm not a gun freak. I haven't been out shooting or hunting in years. Being a good shot is just part of a backwoods Montana upbringing. The Army loves us, we are already good at shooting and living outdoors when we join.

You could just be truly ambidexterous. I'm sure the Army would love that too!

That is what I really liked about the research - it seperated it into right and non-right. Righthandedness is the dominant trait. All other varieties of handedness are recessive. From a geneticist standpoint that makes perfect sense.

It took a yeast genetics researcher to blow open new possibilities in neuroscience. That right there is some powerful thinking-outside-the-box!

In schizophrenia, the part of the brain that is usually lit up on fMRIs during auditory hallucinations is the area of the temporal lobe where hearing is interpreted. This is usually the highlighted result, showing that the schizophrenic really IS hearing a voice that sounds external to them. I haven't read any studies that have seen whether Broca's and/or Wernicke's areas are also activated during auditory hallucinations. Very well may be that the language centers are NOT activated, because the person is hearing what to them seems to be an EXTERNAL voice, and they aren't the person generating the language.

Anyway, I am left-handed, and I know that my left-handedness has to be from my brain not being wired correctly. I only have two other people in my family who are left-handed, and they are both cousins of my mother's who have left-handedness in the part of their family tree I am not related to. Neither of my parents are left-handed. None of my grandparents are left-handed. None of my aunts and uncles are left-handed. But I showed strong left-handed tendencies as early as age 1.

I am interested to read this article, since it's a neuroscience article. I would LOVE to know which hemisphere my language centers are in. Probably left hemisphere, but I wish I could get a Wada's test done to find out for sure.

I think they inferred that left-handedness was simply a random expression of recessive gene. Lefties aren't wired wrong, per se, but wired differently by design. My parents were righties as were my 3 out of 4 of my grandparents. I am the only redhead in 5 generations. I have hazel eyes - my family is predomiantly brown eyed on both sides with a small bit of blond hair/blue eyes along one grandfathers side. Recessive genes are like little hidden time bombs. You never know when they'll go off.

My husband and I both have red hair. Our OB-Gyn assured us it was genetically impossible for us to have anything other than a redheaded child. We have a golden brown haired daughter. recessive/recessive is supposed to equal recessive. This article explain how that may not always be the case.

Just a little bit of knowledge and it has me thinking in so many directions...

I always thought the whole left brain and right brain argument is bull crap. Both of my hemispheres seem to function equally well, although this is strange because I am neither right handed nor left handed.

It's not talking so much about function as placement of functions. Some people have their speech center on the right side, some on the left, some have one in both. I posted a link in an earlier comment to aghogday that talks about how some people do have better communication between both hemisphere of the brain. You might find it interesting.
Title: In Two Minds... a couple posts back.