Extended Data Fig. 2: Additional fMRI results of experiment 1.
From: Activation and disruption of a neural mechanism for novel choice in monkeys
a, The parametric modulation of BOLD signal by the difference in value between the unchosen and chosen options, estimated with GLM 1, activated other clusters beyond the OFC depicted in Fig. 2e. One cluster encompassed numerous areas including ACC, dlPFC, insula (cluster correction for multiple comparisons, with a threshold of Z > 2.3, P = 10−5, peak Z = 4.66 [11.5 2.5 17.5]); others were located in the visual cortex (not illustrated). In a–d, group-level mixed effects were carried out by FSL’s FLAME 1+2. b, We also report an observation highlighting an area likely involved in our task in the midbrain in the vicinity of the ventral tegmental area, (P < 0.001, uncorrected). A similar observation has been made in a task resembling our familiar task in analyses of individual neuron firing rates in the ventral tegmental area (M. Matsumoto, personal communication). c, The contrast of BOLD modulation by the value comparison signal (chosen minus unchosen value) in novel and familiar trials, estimated with GLM 2, which activated MFC as depicted in Fig. 2i, is also visible in the ventral striatum (P < 0.001, uncorrected). A similar observation has been made in a task resembling our familiar task in analyses of individual neuron firing rates in the ventral striatum47. d, fMRI effect of value comparison as in Fig. 2i, but using a subjective estimate of value (whole-brain FWE corrected at Z > 2.3, P = 0.003, peak Z = 3.88 [0 24.5 7.5]). e, Time course of the value comparison signal from GLM2 in OFC (top) in familiar and novel trials separately, in analogy with what reported for MFC in Fig. 2j, replicated here (bottom). All conventions as in the main figures, in particular the coloured shades represent the s.e.m. across sessions. f, Time courses of the component effects (value of chosen option; value of unchosen option) as in Fig. 2g, k but separately for familiar, novel, OFC and MFC. Top row, orbitofrontal ROI; bottom row, medial frontal ROI. g, Time course analysis of the value comparison signal, as in Fig. 2j, but using a subjective definition of value. h, i, Time courses of the parametric modulation of the BOLD signal for the same contrasts as in e and f and ROIs defined in the same way, but time-locked to the stimulus presentation and removing trials with RT > 3 s (coloured shades represent s.e.m.). j, Schema of the relationship between network dynamic and BOLD response. This shows that in a drift-diffusion or an attractor model, if activity falls immediately after the threshold is reached (thick lines in the top panel and bright colours in the bottom panel), the BOLD response will be negatively correlated with value difference, as in macaques; but if the activity is maintained for longer (dotted lines in the top panel and shaded colours in the bottom panel), the BOLD response will be positively correlated with value difference, as in humans (Supplementary Information). Illustration reproduced with permission3. In all panels n = 4 subjects × n = 12 sessions.
