Schematic of functional neuroimaging and local field potentials (LFPs) recording during the monetary incentive delay (MID) task in human subject. (A) Schematic of the MID task, which consists of cue onset, anticipation phase, target onset, and outcome phase. (B) Functional magnetic resonance imaging (fMRI) showing area activated by gain vs. nongain anticipation in the nucleus accumbens (NAc) (white circle; Z > 2.54; cluster, four 3-mm cubic voxels). (C) Blood oxygen level-dependent (BOLD) signal changes during MID task extracted from activated voxels in the left NAc averaged by condition, indicating NAc activation during high reward anticipation compared with baseline [high reward:baseline, T(17) = 3.23, P < 0.01, uncorrected; low reward:baseline, high punishment:baseline, low punishment:baseline, n.s.]. (D) Electrode contact locations in the NAc for LFP recording using preoperative 7-T MRI merged with postoperative computed tomography scan. Coronal view (trajectory view not shown) demonstrates most posterior aspect of electrode trajectory with the following entry anterior–posterior commissure coordinates: x = 41.31, y = 43.39, z = 43.59; 34.2° from midsagittal plane; 60.3° from axial plane; and coordinates for the ventral-most extent of the recording lead: x = 6.03, y = 15.07, z = −6.60. The measurement of 7.5 mm indicates the span of the lead. (E and F) Raw LFPs during baseline and anticipation of high reward. (G) Power density analysis indicating delta range as the frequency region of interest during anticipation period. (H) Power density analysis revealing significant increase in delta power during anticipation of high reward compared with baseline. (I) Normalized NAc LFP power spectrogram (averaged across individual trials), indicating increased delta band (1- to 4-Hz) power during anticipation of high reward (Insets: frequency range from 0 to 50 Hz). **P < 0.01. BL, baseline; HP, high punishment; HR, high reward; LP, low punishment; LR, low reward. See also –.