In spite of this growing evidence that both anterior and posterior medial areas are involved in self-referential thought (see Macrae et al., 2004; Ochsner et al., 2005 for reviews of findings focusing on medial frontal areas, and Vogt and Laureys, 2005; Cavanna and Trimble, 2006, for reviews focusing on medial posterior areas), the relative roles and specific functions of anterior and posterior medial regions during self-reflection remain to be clarified. One approach to clarifying functions of these brain regions is to contrast judgments of the self with the same judgments about others (Ochsner et al., 2004, 2005). Another approach is to contrast different types of judgments about the same targets (e.g. mentalistic vs perceptual, Mitchell et al., 2005). A third approach, which we have taken here, is to contrast different types of self-relevant thoughts, in this case, about one's agendas (i.e. goals, e.g. Johnson and Reeder, 1997).

Motivationally significant agendas guide our perception, thought and behaviour, helping to define a ‘self’ and to regulate our interactions with others and the general environment. As discussed above, studies investigating neural correlates of self-relevant processing often ask participants for judgments about the self-relevance of traits. However, in characterizing a self, an individual's agendas (e.g. to have a family, become an actor, keep healthy, pay the bills) are perhaps as equally important as their traits and are a frequent target of self-reflection in everyday life. Furthermore, just as there are a multitude of traits that can describe a self, there are a multitude of potential agendas, from the immediate (e.g. finding a restaurant) to the longer term [e.g. making progress on a life task (Cantor and Kihlstrom, 1987) or achieving a possible future self (Markus and Nurius, 1986)].

Nevertheless, at a relatively abstract level of categorization, agendas may be divided into two broad classes based on the two self-regulatory, motivational systems proposed by Higgins (1997, 1998): promotion and prevention. A promotion orientation is associated with seeking advancement and accomplishment, whereas a prevention orientation is associated with concerns of safety and responsibility. This distinction is based on the idea that while individuals generally approach pleasure and avoid pain, the nature and relative importance of seeking pleasure and avoiding pain differs across individuals and within individuals across situations (see also Carver and White, 1994).

The idea of variation in individuals’ regulatory focus highlights the difference between agendas and traits; two people could both be described by the trait ‘planful’, but planful about what? A person with a predominantly promotion focus would be more likely to be planful about attaining positive rewards or outcomes, while a person with a predominantly prevention focus would be more likely to be planful about avoiding negative events or outcomes. Although a promotion or prevention focus may dominate, the aspects of the self that are active change dynamically across situations (e.g. Markus and Wurf, 1987), thus most individuals have both promotion and prevention agendas. For example, the same person can hold both the hope of becoming rich (a promotion agenda) and the duty to support an aging parent (a prevention agenda), or the aspiration to be a good citizen and the obligation to be a well-informed voter. As individuals, hopes and aspirations and duties and obligations make up a large part of our mental life and constitute the motivational scaffolding for much of our behaviour.

Higgins and colleagues have reported a number of findings from behavioural studies consistent with their self-regulatory framework (e.g. Higgins et al., 1997; Shah and Higgins, 2001; Freitas and Higgins, 2002). For example, Freitas and Higgins (2002) found that individuals rated a search task as more enjoyable when the goal was framed to be consistent with their orientation (e.g. finding helpful elements for promotion-focused individuals and finding harmful elements for prevention-focused individuals). Rating the emotionality of words was faster when ratings were along orientation-consistent emotional dimensions (Shah and Higgins, 2001).

A recent neuroimaging study provides converging evidence that self-regulatory focus influences attentional processes and affective responses. Cunningham et al. (2005) found that during an evaluative task in which participants made judgments about the valence of concepts (e.g. recycling, terrorism, love, affirmative action), activity in the amygdala, anterior cingulate cortex and extra-striate cortex was correlated with the participants’ scores on a later promotion/prevention questionnaire. Specifically, a promotion focus was associated with sensitivity to positive stimuli in these regions and a prevention focus was associated with sensitivity to negative stimuli in these same regions, suggesting that regulatory focus may tune a single neural system to detect motivationally significant stimuli. Although the Cunningham et al. (2005) study provides support for the idea that self-regulatory orientation modulates processing of externally presented stimuli, to our knowledge, the neural activity associated with self-reflection in the context of a promotion focus vs a prevention focus has not been investigated.

The present studies investigated neural activity when participants were asked to think about self-relevant agendas related to either a promotion (think about your hopes and aspirations) or prevention (think about your duties and obligations) focus. We compared neural activity associated with thinking about these two different types of self-relevant agendas and with thinking about non-self-relevant topics (distraction). We expected greater activity in anterior and/or posterior medial regions associated with these two self-reflection conditions compared with the distraction control condition because thinking about one's agendas, like thinking about one's traits, is self-referential. Such a finding would also be consistent, for example, with Luu and Tucker's (2004) proposal that both anterior cingulate and posterior cingulate cortex contribute to action regulation by representing goals and expectancies.

Clinical findings also suggest that there should be differences in neural activity associated with self-reflection vs distraction. Behavioural data show that the distraction manipulation used here provides a short-term reduction of negative self-relevant thought in people prone to depression, with a concomitant reduction in depressed mood (Nolen-Hoeksema, 2004). If distraction reduces self-focused rumination, we might expect to find less activity in brain areas associated with self-focus in distraction compared with self-reflection conditions.

In Experiment 1, self-reflection was induced prior to scanning using a between subjects essay task that focused some participants on their hopes and aspirations (promotion focus) and others on their duties and obligations (prevention focus) (Freitas and Higgins, 2002). These promotion and prevention inductions, like the rumination inductions used in behavioural studies of depression (e.g. Nolen-Hoeksema, 2004), encouraged attention to the self but were more goal-directed than those typically used in rumination studies (e.g. where participants might be asked to think about how they are feeling). During scanning, short periods of self-reflection about the pre-scan essay agenda were intermixed with distraction. The distraction condition used items (e.g. think about polar bears fishing) from the standard distraction condition in previous behavioural rumination studies (Nolen-Hoeksema, 2004). Experiment 2 was a completely within-subjects design in which there was no pre-scan essay induction phase. Rather, focus was induced ‘online’ with randomly intermixed promotion, prevention and distraction prompts. Experiment 2 thus provided information about whether the same regions were identified in promotion and prevention self-focus when participants were asked to flexibly consider both promotion and prevention agendas on different trials as when a single type of self-focus was repeatedly engaged over an extended period, as in Experiment 1. In both experiments, marked differences in patterns of neural activity in anterior and posterior medial cortex during self-reflection compared with distraction were observed, as well as a double dissociation between anterior and posterior medial regions in the relative activity levels during promotion and prevention focused self-reflection.

Figure 2 shows data from medial cortical regions identified in Experiment 2. Again, an area of anterior cingulate/dorsomedial PFC (Figure 2A) and an area of posterior cingulate, precuneus (Figure 2B) showed greater activity during self-reflection than distraction, and no difference between promotion and prevention conditions. In contrast, in other medial areas, we found greater activity for the promotion than prevention condition (anterior cingulate, Figure 2C) and greater activity for the prevention than promotion condition (lingual gyrus, posterior cingulate, Figure 2D). The local maximum of the medial PFC region showing the largest promotion > prevention difference in Experiment 2 (Talairach coordinates: x=2, y=39, z=−1) was within two voxels of the local maximum in Experiment 1 (1, 45, 4). The local maximum of the posterior medial region showing the largest prevention>promotion difference in Experiment 2 (−10, −53, 2) was more inferior and posterior than the local maximum found in Experiment 1 (−1, −34, 20). Both regions (Figures 1D and ​and2D)2D) were, however, anterior to those showing equal activation in promotion and prevention conditions (Figures 1B and ​and22B).¹

A double dissociation was found when participants were cued to think about promotion and prevention agendas on different trials for the first time during scanning (Experiment 2) and when they spent several minutes thinking about either promotion or prevention agendas before scanning (Experiment 1), indicating that it results from what participants are thinking about during the scan and not from some general effect (e.g. mood) carried over from the pre-scan period of self-reflection. However, the fact that the anterior medial region showing greater activity when participants thought about hopes and aspirations was more similar across experiments than the posterior medial region showing greater activity when participants thought about duties and obligations suggests that perhaps posterior medial cortex is more sensitive to a within vs between subjects manipulation of self-reflection than is anterior medial cortex.

We also obtained participants’ prevention and promotion scores on a brief questionnaire assessing more chronic promotion and prevention orientation (Cunningham et al., 2004). For each participant for each region in Figure 1 or Figure 2, we found the maximum percent change in each trial and averaged across trials. These mean peak percent changes were correlated with the promotion and prevention orientation scores. In Experiment 1, promotion orientation scores were positively correlated with activity in medial PFC (area shown in Figure 1C) during promotion trials, r=0.69, P<0.04, suggesting that activity in this area may reflect a combination of state and trait factors. No other correlations approached significance.

Although anterior and posterior medial regions are of primary interest here, other regions identified in the whole brain analyses of Experiments 1 and 2are shown in Tables 1 and ​and2,2, respectively.

A novel finding in both experiments was that, relative to distraction, a more inferior area of medial PFC was more active during promotion oriented self-reflection and an area of posterior cingulate was more active during prevention oriented self-reflection. Given the procedural differences between Experiments 1 and 2 (self-reflection focus was manipulated between participants in Experiment 1 and within participants in Experiment 2; participants wrote a self-reflective essay in advance of scanning in Experiment 1 and did not engage in self-reflection prior to scanning in Experiment 2), the replication of a double dissociation between the type of self-reflection (promotion vs prevention) and activity in medial PFC vs posterior cingulate regions is particularly striking.

Ochsner et al. (2005) and Mitchell et al. (2005) recently speculated that different regions of medial PFC may have somewhat different functions. Ochsner et al. (2005) subdivided medial PFC into ventral (z<10) and dorsal (z>10) regions and proposed that they may be involved in maintaining different types of representations, with ventromedial PFC maintaining representations of affective and motivational states and dorsomedial PFC maintaining more symbolic representations involved in describing and reasoning about these states. Mitchell et al. (2005), using what appears to be a division along the z-dimension of about 17 [see Table 4 in Mitchell et al. (2005)], suggested that ventromedial PFC activity may be associated with self-referential processing and dorsomedial PFC activity may ‘instantiate more universally applicable social-cognitive processes’ (p. 1311). In Tables 1 and ​and2,2, we have followed the suggested nomenclature for Social Cognitive and Affective Neuroscience that divides anterior medial PFC into three regions: ventromedial PFC (z<−10), medial PFC (−10<z<27) and dorsomedial PFC (z>27). Thus the area of medial PFC for which we found greater sensitivity to thinking about hopes and aspirations than to thinking about duties and obligations (Figures 1C and ​and2C),2C), falls within the region labelled ventromedial by Ochsner et al. (2005) and Mitchell et al. (2005). If, compared with dorsomedial PFC, a more inferior medial (or ventromedial) region is more specifically self-referential or more associated with motivation, then our findings would suggest that for our young adult participants, hopes and aspirations may be more closely related to the sense of self than duties and obligations, or that they are more motivated or emotionally engaged by thinking about hopes and aspirations than duties and obligations (Figures 1C and ​and22C).

In addition to providing evidence that further specifies the dissociation of function between different regions of anterior medial frontal cortex, our findings provide new evidence that different areas of posterior medial cortex may also subserve different functions with respect to self-reflective processing. In both Experiments 1 and 2, the posterior medial regions (Figures 1D and ​and2D)2D) in which thinking about duties and obligations resulted in relatively greater activity than thinking about hopes and aspirations were somewhat anterior and inferior to those regions that were equally active for both types of self-reflection (Figures 1B and ​and2B).2B). There is emerging evidence of differences in cytological organization and circuitry associated with the ventral and dorsal posterior cingulate (Vogt and Laureys, 2005). Interestingly, Vogt and Laureys suggest that ventral posterior cingulate may play a greater role in emotional processing than does dorsal posterior cingulate, through connections with anterior cingulate cortex. With respect to the precuneus, Cavanna and Trimble (2006) make an anterior (y closer to −60) vs posterior (y closer to −70) distinction, and their review suggests that more anterior regions tend to be found in studies of self-processing [see Table 4 in Cavanna and Trimble (2006)] and more posterior regions are more likely to be found in studies of episodic retrieval [see Table 3 in Cavanna and Trimble (2006)]. These reviews indicate that both dorsal/ventral and anterior/posterior differences will be of interest in future investigations of the role of medial posterior cortex.

In short, the double dissociation between medial PFC and anterior/inferior medial posterior areas and our two self-reflection conditions indicates that these brain areas serve somewhat different functions during self-focus. There are a number of interesting possibilities that remain to be sorted out. Differential activity in these anterior medial and posterior medial regions as a function of the types of agendas participants were asked to think about could reflect: (i) differences in the representational content in the specific features of agendas, schemas, possible selves and so forth that constitute hopes and aspirations on the one hand and duties and obligations on the other (cf. Luu and Tucker, 2004); (ii) differences in the type(s) of component processes these agendas are likely to engage and/or the representational content they are likely to activate, for example, discovering new possibilities (hopes) vs retrieving episodic memories (e.g. Maddock et al., 2001) of past commitments (duties); (iii) differences in affective significance of hopes and aspirations (attaining the positive) and duties and obligations (avoiding the negative, Higgins, 1997; 1998); (iv) different aspects of the subjective experience of self, such as the subjective experience of control (an instrumental self) vs the subjective experience of awareness (an experiential self; Johnson, 1991; Johnson and Reeder, 1997; compare, e.g. Searle, 1992 and Weiskrantz, 1997, vs Shallice, 1978 and Umilta, 1988); (v) differences in the social significance of hopes and aspirations (more individual) and duties and obligations (involving others). This last possibility is suggested by findings linking the posterior cingulate with taking the perspective of another (Jackson et al., 2006). It may be that thinking about duties and obligations (a more outward focus) tends to involve more perspective-taking than does thinking about hopes and aspirations (a more inward focus). The greater number of mental/emotional references from the promotion group on the pre-scan essay and the tendency for a greater number of references to others from the prevention group are consistent with the hypothesis that medial PFC activity is associated with a more inward focus whereas posterior cingulate/precuneus activity is associated with a more outward, social focus. Clarifying the basis of the similarities and differences between neural activation associated with thinking about hopes and aspirations vs duties and obligations would begin to help differentiate the relative roles of brain regions in different types of self-reflective processing.

Finally, the present findings suggest more specific target regions for investigating the impact of various types of self-reflection and distraction in clinical compared with non-clinical populations in future studies. Many psychological disorders appear to involve disruption of the sense of self, for example, a loss of agency or ownership of ideas (schizophrenia), loss of control of emotions (anxiety, depression) or unstable self-image (borderline personality disorder). Exploration of potential differential disruption in dorsomedial, medial and ventromedial PFC and identifiable posterior cingulate/precuneus components of a self-reflection/self-regulation circuit in these clinical populations should yield further information about the relative contributions of these regions to self-reflection and self-regulation, and to cognition and emotion more generally.