In a recent study on reward processing in alcoholics during a gambling task, event-related theta band (3.0–7.0 Hz) oscillations were evaluated during the loss/gain feedback (Kamarajan et al., 2012). The alcoholic group showed significantly decreased theta power during reward processing compared to controls, particularly during the evaluation of loss. Current source density maps of alcoholics revealed weaker and diffuse source activity for all conditions and weaker bilateral prefrontal sources during loss while the controls manifested stronger and more focused midline sources. Alcoholics also exhibited increased impulsivity, risk taking (as revealed by behavioral measures), and a strong association between reduced anterior theta power and impulsive task performance. Decreased power in theta oscillations and more diffuse current density may be due to reorganized and inefficient neural reward network in alcoholics.
