Motivation and Motor Control: Hemispheric Specialization for Motivation Reverses with Handedness

What is the relationship between action and emotion? People tend to perform approach actions with their dominant hand and avoidance actions with their nondominant hand. In righthanders, the left frontal lobe (which controls the dominant hand) is specialized for approach-motivational states, and the right frontal lobe (which controls the nondominant hand) for avoidance-motivational states. Are brain areas that support affective motivation functionally related to areas that support approachand avoidance-related motor actions? If so, hemispheric specialization for motivation should covary with hemispheric specialization for motor control. Here we tested this prediction, using electroencephalography (EEG) to compare resting alpha-band power in rightand left-handers. Hemispheric asymmetries in alpha-power, which indexes neural activation, were related to Behavioral Activation System (BAS) scores, which index approach-motivational tendencies. Results show that the pattern observed in righthanders reverses in left-handers, whose right hemisphere is specialized for both approach motivation and for control of dominant-hand actions. This anatomical covariation suggests a functional link between affective motivation and motor control, and also provides information crucial for developing neural therapies for affective disorders.