ARTICLE UPDATE - Impact of motivational salience on affect modulated startle at early and late probe times.

David E. Gard, Marja Germans Gard, Neera Mehta, Ann M. Kring and Christopher J. Patrick

International Journal of Psychophysiology, in press

This study systematically manipulated both picture content and noise probe time in order to evaluate the effects of motivational salience (as distinguished from affective valence) on both early and late modulation of the startle response. Specifically, modulation was compared for erotic versus action/adventure scenes, and for direct threat versus victim scenes, at early (300 and 800 ms) and late (3500 ms) probe times — all relative to neutral. Blink inhibition was observed at all probe times during presentation of erotic pictures, and blink potentiation was evident at all times during presentation of direct threat pictures. Patterns of blink modulation were less consistent for action and victim picture contents. These findings are consistent with the hypothesis that under conditions of high motivational salience, affective startle modulation indexes the activation of appetitive-approach and defensive motivational states, even at early stages of picture processing.

ARTICLE UPDATE - Interrelations between motivational stance, cortical excitability, and the frontal electroencephalogram asymmetry of emotion: A trans

Schutter DJ, Weijer AD, Meuwese JD, Morgan B, Honk JV.

Human Brain Mapping, in press

Several electrophysiological studies have provided evidence for the frontal asymmetry of emotion. In this model the motivation to approach is lateralized to the left, whereas the motivation to avoidance is lateralized to the right hemisphere. The aim of the present experiment was to seek evidence for this model by relating electrophysiological and phenomenological indices of frontal asymmetry to a direct measure of cortical excitability. Frontal asymmetrical resting states of the electroencephalogram and motivational tendencies indexed by the Carver and White questionnaire were compared with neural excitability of the left and right primary motor cortex as assessed by transcranial magnetic stimulation in 24 young healthy right-handed volunteers. In agreement with the model of frontal asymmetry, predominant left over right frontal cortical excitability was associated with enhanced emotional approach relative to emotional avoidance. Moreover, the asymmetries of brain excitability and approach-avoidance motivational predispositions were both reflected by frontal beta (13-30 Hz) electroencephalogram asymmetries. In conclusion, the currently demonstrated interconnections between cortical excitability, electrophysiological activity, and self-reported emotional tendencies for approach or avoidance support the frontal asymmetry of emotion model and provide novel insights into its biological underpinnings. Hum Brain Mapp 2007.