Cognitive correlates of affect-induced alpha asymmetry

Are low levels of lateralized EEG-alpha (as an indication of activation) attributable to positive versus negative affect generation (Davidson, 1993; Harmon-Jones, 2003) or to the counteracting these processes (Rotenberg, 2004)? Previous literature on functional brain asymmetry suggests that relative left frontal cortical activity is associated with positive affect and approach motivation and that the relative right hemispherical activity is associated with negative affect and withdrawal motivation 1992; Harmon-Jones, 2003). It has been shown that organic damage to the left hemisphere is usually accompanied by depressed mood, whereas damage to the right hemisphere is 1988). These findings led to the hypothesis that the left hemisphere supports the maintenance of pleasant affect, whereas and the right hemisphere supports the maintenance of unpleasant affect (Heller, 1990). However, theoretical notions and empirical findings exist in the literature that contradict this view Tucker (1981), for example, hypothesized that the observed emotional state reflects a disinhibition of the ipsilateral subcortical area of the damaged hemisphere. Thus, negative affect reflects the disinhibited activity of the left subcortical area, whereas positive affect reflects the disinhibited activity of the right hemisphere. Indeed, more recent research based on fMRI partly supports this hypothesis by revealing that left more so than right subcortical areas (amygdale, hypothalamus, thalamus) play a role in responses to unpleasant stimuli Likewise, it has been shown that the right hemisphere has a clear advantage in creative solution of problems (Bowden and Beeman, 1998), which has been considered a mental process strongly associated with approach rather than withdrawal behavior. For example, demonstrated in a series of experiments that incentive-related (" positive ") approach motivation facilitates creative problem solving, and that this effect is mediated by right hemispheric activation. Contray, Friedman and Förster (2005) also showed that avoidance motivation faciliates analytic problem solving, and that this effect is mediated by left