336 PHAN ET AL. While th e may not be a particular brain both emotion without Cognitive De ation of th flect that ntral MPEC 1 nd 2C).Inte tain a ects may be shared across differ nt emotional vious meta-analyse sof cognition revealed that the tasks.Figure 2A shows that the MPFC was activated rostral-ventral and orbital regions of the MPFC are across multiple individual emotions (four of five spe argely insensitive to cognitive tasks (Duncan and cific emoti ons in at 40%oI stu Owen,2000:Cabeza and Nyberg.2000). he MPEC a to st that the MPFC 2.Regions Associated with Individual Emotions may have a general role in emotional processing.as 2.1 Fear and the amygdala.Specifically,fear induc suggested by Lane. Reiman and colleagues,whe tion had a strong association with the amygdala.Sixty ported that emotional films,pictures and recall percen ed t em y9 12 nd the of these th he is res ponsible for detecting. generating.and maintain- Lane et al 1997c:Re an et al1gg7刀This is co tent with the notion that a number of processes are potentially various emotional tasks (e.g. s(Adolphs et al. der et al. 1996 appraisa n吧 ter et a (D 100 (1997)did find the 005. aubiects inter allv-atte nded to their nal state al 1998b)and in evocation of fearful emotional re not when they externally atte nded to nonaffective sponses from direct stimulation (Halgren et al.,1978). cha acter of a picture stimulus.Furthermore,ac The amygdala al Iso appears importan t in the detection tivity to co elate with envronment threa Scott 1997 Isenberg e emo a 0 an recal et a as ir ate th (Kluber Bucy 193 :Weiskra 1g56 et al 1998)One n ossibility therefore is that the King.1992).Strikingly,of the eight studies that exam- MPFC may be involved in the cognitive aspects (e.g. ned cerebral responses to fearful faces,six pointed to attention to emotion,appraisal emo tical involvement of the a amygd a orris et a of emotional processing (Drevets and 199 en the tivation als tion into other modalities such as words (Ise nbera et al vided into affective and cognitive regions,which has 1999)and vocalizations (Phillips 1998a).Morris et al been observed in the ante rio cingulate cortex (ACC) 1996)found that the amy ygdalar response to fearful (Bush e 2000 ACC is nown to b olved in aces ant raction with th form n that serves emo sing with incre th ta.2000 d to th of facial as subie MPEC (Petrides and Pandya.1999:Devinsky et al. were instructed to classify en notional faces by ender 1995).Figures 1A and 1B show that activatic ns re- not by emotion.Such an interpretation is further ported in the prefrontal cortex in response to different n from studies ng masked are ces wh amygo of e the ate cortex (Accad)(BA rostral 24 anterior/ven erience ubjectively (Morris et al..1998b: tral 32,33).While the activations located in the area of Whalen et al..1998a) the MPFC are more ventral and less dorsal,we did not Given that f ar is the most salient of the individual nnd any e or an alternative interpretation for the amyg. e s a mo. gen tha eaks fell into dor sal MPEC (se Fig 10) L 20011 son to studies with tasks that involved Emotion and Whalen et al.(1998b)observed that the amygdala re- Cognition.Thus.MPFC appears equally sensitive to sponds to fearful faces despite the lack of explicit rec- While there may not be a particular brain region that is absolutely necessary for all emotional functions, the common activation of the MPFC may reflect that cer￾tain aspects may be shared across different emotional tasks. Figure 2A shows that the MPFC was activated across multiple individual emotions (four of five spe￾cific emotions in at least 40% of studies). Accordingly, X2 analysis revealed no specific association between the MPFC and Individual Emotion as compared to other regions. These findings suggest that the MPFC may have a general role in emotional processing, as suggested by Lane, Reiman, and colleagues, who re￾ported that emotional films, pictures, and recall as wells as positive and negative emotion, happiness, sad￾ness, disgust, and the mixture of these emotions all separately engaged the MPFC (Lane et al., 1997a; Lane et al., 1997c; Reiman et al., 1997). This is consis￾tent with the notion that a number of processes are potentially common to various emotional tasks (e.g., appraisal/evaluation of emotion, emotional regulation, and emotion-driven decision-making). Lane et al. (1997b) did find that the MPFC (BA9) activated when subjects internally-attended to their emotional state, but not when they externally attended to nonaffective characteristics of a picture stimulus. Furthermore, ac￾tivity in the MPFC has been shown to correlate with emotional awareness to both film and recall-generated emotion, suggesting its role in detecting emotional sig￾nals from both exteroceptive and interoceptive cues (Lane et al., 1998). One possibility therefore is that the MPFC may be involved in the cognitive aspects (e.g., attention to emotion, appraisal/identification of emo￾tion) of emotional processing (Drevets and Raichle, 1998). Given the putative importance of cognition in emo￾tion, we questioned whether the MPFC can be subdi￾vided into affective and cognitive regions, which has been observed in the anterior cingulate cortex (ACC) (Bush et al., 2000). The ACC is known to be involved in a form of attention that serves to regulate both cogni￾tive and emotional processing (Whalen et al., 1998a; Bush et al., 2000), and is closely interconnected to the MPFC (Petrides and Pandya, 1999; Devinsky et al., 1995). Figures 1A and 1B show that activations re￾ported in the prefrontal cortex in response to different Individual Emotions and Induction Methods are lo￾cated within ventral-rostral BA 9 and 10 of MPFC, and extend into the affective division of rostral anterior cingulate cortex (ACCad) (BA rostral 24, anterior/ven￾tral 32, 33). While the activations located in the area of the MPFC are more ventral and less dorsal, we did not find any evidence for a functional affective-cognitive division of the MPFC. Our Cognitive Demand analysis revealed that relatively much fewer Emotion alone peaks fell into dorsal MPFC (see Fig. 1C), in compari￾son to studies with tasks that involved Emotion and Cognition. Thus, MPFC appears equally sensitive to both emotional tasks with and without Cognitive De￾mand, as activations from both conditions cluster in ventral MPFC (see Figs. 1C and 2C). Interestingly, previous meta-analyses of cognition revealed that the rostral-ventral and orbital regions of the MPFC are largely insensitive to cognitive tasks (Duncan and Owen, 2000; Cabeza and Nyberg, 2000). 2. Regions Associated with Individual Emotions 2.1 Fear and the amygdala. Specifically, fear induc￾tion had a strong association with the amygdala. Sixty percent of studies that examined fear activated the amygdala (X2 12.57, P 0.01) (Fig. 2A). Several lines of evidence support the notion that the amygdala is responsible for detecting, generating, and maintain￾ing fear-related emotions. Particularly, the amygdala has been implicated in the recognition of fearful facial expressions (Adolphs et al., 1995; Calder et al., 1996), feelings of fear after procaine induction (Ketter et al., 1996), fear conditioning (LeDoux, 1993; Bechara et al., 1995; LaBar et al., 1995; Morris et al., 1998b; Whalen et al., 1998b), and in evocation of fearful emotional re￾sponses from direct stimulation (Halgren et al., 1978). The amygdala also appears important in the detection of environment threat (Scott et al., 1997; Isenberg et al., 1999; Phillips et al., 1998a), as well as in the coordination of appropriate responses to threat and danger (Kluber and Bucy, 1939; Weiskrantz, 1956; King, 1992). Strikingly, of the eight studies that exam￾ined cerebral responses to fearful faces, six pointed to the critical involvement of the amygdala (Morris et al., 1996; Breiter et al., 1996; Phillips et al., 1997; Phillips et al., 1998a; Morris et al., 1998a; Whalen et al., 1998a). Fear-associated amygdalar activations also extended into other modalities such as words (Isenberg et al., 1999) and vocalizations (Phillips 1998a). Morris et al. (1996) found that the amygdalar response to fearful faces showed a significant interaction with the inten￾sity of emotion (increasing with increasing fearfulness) and that the activation was not contingent upon the explicit processing of facial expression, as subjects were instructed to classify emotional faces by gender not by emotion. Such an interpretation is further strengthened by findings from studies using masked fearful faces which found that the amygdalar response occurred even when the fearful expression was not consciously perceived or even when subjects did not experience fear subjectively (Morris et al., 1998b; Whalen et al., 1998a). Given that fear is the most salient of the individual emotions, an alternative interpretation for the amyg￾dala’s involvement is that it has a more general role for vigilance or for processing salience, or attributes that make stimuli meaningful (Davis and Whalen, 2001). Whalen et al. (1998b) observed that the amygdala re￾sponds to fearful faces despite the lack of explicit rec- 336 PHAN ET AL.