Even though this theory is the commonly conveyed in the majority of articles and books, there is a growing amount of data showing that when we move an hand or an arm the activity in both the contralateral and the ipsilateral hemispheres are simultaneously activated. The neurophysiological significance of the bilateral activation of the motor cortices remains unclear. Kobayashi et al (2003) suggested that “ipsilateral activation during non-dominant hand movements could reflect an increased inhibition exerted by the right over the left hemisphere through callosal fibers”. Others support the idea that all movements are initiated in the dominant hemisphere with the non-dominant would be responsible just for the execution of the command issued by the dominant hemisphere (e.g. Derakhshan I, 2004). Do you know any paper reporting neurophysiological evidence (e.g. EEG or fMRI recordings) in support of one or the other hypothesis?
Kobayashi M, Hutchinson S, Schlaug G, Pascual-Leone A (2003) Ipsilateral motor cortex activation on functional magnetic resonance imaging during unilateral hand movements is related to interhemispheric interactions. NeuroImage 20: 2259–2270.
Derakhshan I. Callosum and movement control: case reports. Neurol Res. 2003; 25: 538-442.
Very important question of the correlation between the activity in the right and left hemispheres of the brain and limb movement with only one side of the body. Here we can better understand not only the physiology of movements. Knowing this mechanism, we can develop new technologies to restore movements in lesions of structures of one hemisphere. I recommend reading some articles, in which there are a number of answers to these questions. Good luck in resolving outstanding hypothesis.
Beloozerova I.N., Sirota M.G., Swadlow H.A., Orlovsky G.N., Popova L.B., Deliagina T.G. Activity of different classes of neurons of the motor cortex during postural corrections. J. Neurosci. 2003. Vol. 23 (21). P. 7844-7853.
Beloozerova I.N., Sirota M.G. Swadlow H.A. Activity of different classes of neurons of the motor cortex during locomotion. J. Neurosci. 2003. Vol. 23 (3). P. 1087-1097.
You can also have a look at our paper
Tallet, J., Albaret, J.-M., & Barral, J. (2013). Age-related changes in inter-hemispheric communication tested with a motor selective inhibition task in children with and without Developmental Coordination Disorder. Research in Developmental Disabilities, 34, 2523-2532.
Great Question! There has been a great deal of work since Kobayashi et al.'s paper and there isn't a consensus (not surprising) respective of locus of motor activity. We've been exploring the differences in aging respective of motor performance using a unimanual task paradigm and have found that aging confers a loss of interhemispheric inhibition and dexterity. However, aerobic exercise ameliorates the loss of inhibition (again in a unimanual task paradigm). This doesn't necessarily argue for a contralateral locus of motor control, but does provide evidence that the ipsilateral cortex is strongly influenced by transcallosal inhibition in a unimanual task paradigm. See McGregor et al., 2013 below for details.
However, there is an excellent paper by Diedrichsen et al., (2013) in Cerebral Cortex that shows that there may be a differentiation of ipsilateral cortical involvement based on task demands. That is, during a bimanual task, the activity of the ipsilateral cortex of the non-dominant (though still task active) is largely influenced by parietal and supplementary motor areas. As such, there appear to be distinct circuits required for bimanual versus unimanual action.
McGregor KM, Nocera JR, Sudhyadhom A, Patten C, Manini TM, Kleim JA, Crosson B, Butler AJ. Effects of aerobic fitness on aging-related changes of interhemispheric inhibition and motor performance. Front Aging Neurosci. 2013 Oct 30;5:66. doi: 10.3389/fnagi.2013.00066.
Diedrichsen J, Wiestler T, Krakauer JW. Two distinct ipsilateral cortical representations for individuated finger movements. Cereb Cortex. 2013 Jun;23(6):1362-77. doi: 10.1093/cercor/bhs120. Epub 2012 May 17.
The contralaterality theory is still much valid. However, it is very important to note that only 90% of the fibre go contralateral the rest 10% are ipsilateral. Therefore a motor activity will cause activities in both hemisphere
The concept of interhemispheric inhibition and interhemispheric unbalance is enough studied in neurological rehabilitation.
A lot of studies, performed by fMRI, have shown that in the motor recovery after stroke there are two options:
the patients recovery by an activation of ipsilateral connection in healthy hemisphere; the recovery is related to an increased activation of damage hemisphere which is controlateral to affected body side.
In the former the functional recovery after stroke is worst than in the latter.
It seems that the healthy hemisphere works by an inhibition of damage hemisphere and some rehabilitation methods (i.e. tDCS or TMS) are used in order to avoid this inhibition.
A lot of papers are available in the literature (see pubmed)
The contralateral cortex does always seem to be involved. You might check an interesting study of ours
Stable ratio of pistillate real to contralateral sensory motor cortex activity despite varying effort and peripheral nerve block. Archer et al J Clin Neuroscience 2004:11;46-52
There is also good evidence that the ipsillateral cortex can control movement with loss of cortex in stroke trauma, cerebral palsy etc.
That should read ipsilateral -sorry the iPad made it 'pistillate real'. Now how does that work?
That's interesting, I am a Rehabilitation Psychologist working in the field of Developmental disabilities. Can anybody guide me a model or assessment technique to check this phenomenon. I can test this across the ages and in male and female.
Say for an instance, I want to see the effect of intentional movement of one hand on the other (let's begin with the hypothesis that right hand is controlled by left hemisphere) and to check this I use Seguine Form Board (SFB) (It is a board which consists of 9 geometric figures and the child has to arrange the shapes in the corresponding grooves). In this experiment, the child is asked to use one hand to arrange the geometric shapes and the non-working hand shall be placed on the lump of clay. My hypothesis would be there should be no/minimal pressure on the lump of clay while one is at work. How would this idea be? and if I start suggesting the child to relax the non-working hand eventually providing manual feedback, would that improve the condition?
Please let me know your suggestions.
Dear Joshi, the goal with intellectual disabled children should be to achieve the complementarity of both hands. Perhaps the best way is by doing easy jobs with meaning for children. At first, one hand must learn to hold and the other to act, for example by cutting a material. With teenagers it may be useful origami. In this case the first goal is to learn to fold a paper in half. If they are not very dyspraxic they will learn to make planes or boats to play with them later. Another good activity is to braid or tie ropes or twigs.
From the several different answers I have got, I can still get the idea that this is a very controversial issue. Did anyone record electrocorticography during reaching movements? This technique might lead to uncover whether or not the contralateral hemispere is involved and what is its role. Thanks to all for suggesting several interesting papers
I believe that the question of the ipsi- or contralateral control motor functions important for improvibg patient management. We have some structural basis for such tactics of therapy. I'm talking about the subcortical nuclei, and nuclei of the reticular formation of the brain. How to learn to harness the potential of these regions of the brain after trauma or hemorrhage in the cerebral hemispheres of the brain?
Q: Is the contralaterality of motor control a defunct theory?
A: Yes.
Methodology and Proof: Bimanual simultaneous drawing task.
If a normal person draws two lines (or two boxes) simultaneously with both hands, the lines (or boxes) drawn by the neutrally dominant hand will be longer and straighter (or the boxes drawn by the neurally dominant hand will be larger and have more definitively shaped angles) compared to those drawn by the nondominant hand.
It has been demonstrated repeatedly that whereas the neurally dominant hand is directly connected to the hemisphere of action (i.e. the major hemisphere, speech hemisphere) the connection of the nondominant hand to the action hemisphere is via the corpus callosum, making that hand retarded compared to the dominant hand by an interval equal to the interhemispheric transfer time (IHTT).
Reference:
Derakhshan I. Handedness: neural versus behavioural.
Eur J Neurol. 2002 Nov;9(6):701-2; author reply 702
I might add following paper of our group that contributes to this discussion:
Hand movements with a phase structure and gestures that depict action stem from a left hemispheric system of conceptualization.
I Helmich, H Lausberg
Experimental Brain Research
06/2014; DOI:10.1007/s00221-014-4006-x
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