Source localization of brain electric activity during positive, neutral and negative emotional states

In order to clarify the differences in source localization of brain electric activity between positive, neutral and negative emotional states, we recorded 19-channel, eyes-closed EEG: (a) before and after autogenic training in 12 right-handed normal subjects (5 males, 7 females, mean age 22.3±1.9 years) and (b) during listening to independently assessed joyful and sad music in 12 right-handed normal subjects (5 males, 7 females, mean age 23.6±1.8 years). Forty artifact-free seconds/subject/condition were analyzed using FFT Dipole Approximation and Low Resolution Electromagnetic Tomography (LORETA). Global tests revealed differences (p<0.06) between source gravity center locations of the (excitatory) beta3 frequencies (21.5–30 Hz): (a) before and after autogenic training, and (b) during the two emotional music experiences. Post-hoc, paired t-tests (p<0.2) showed that the sources were located: (a) more posterior-left for beta3 after than before autogenic training, and (b) more posterior-inferior for beta3 during joyful than sad music. LORETA specified (with p<0.05) that autogenic training compared to rest produced the weakest activity in right Brodmann area 6 (frontal lobe), right Brodmann area 6, and middle Brodmann area 10 (frontal lobe) for routine/resting alpha2 frequencies (10.5–12 Hz), excitatory beta2 (18.5–21 Hz), and beta3, respectively. Also, LORETA specified (with p<0.05) that joyful music showed maximally weaker activity than sad music in left Brodmann area 36 (temporal lobe) for routine/resting or inhibitory theta frequencies (6.5–8 Hz). Thus, the three emotional states (positive such as relaxation after autogenic training and during joyful music, neutral such as resting before autogenic training, and negative such as during sad music) were clearly associated with activity of different neural populations in the brain; i.e., positive emotions were generally related to posterior-left-inferior brain electric activity compared to neutral and negative emotions.