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lindagray

EXAMINING REAL-TIME RACE-BASED PROCESSES OF DISCRIMINATION IN THE BRAIN

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In the past, studying the brain directly required waiting until death to perform an autopsy or using methods too indirect to capture the subtleties of brain function. Now, with the use of methods to map the human brain, we can map hallucinations as they occur or elucidate the complex circuits and structures in the brain associated with emotions such as sadness, joy, anger, pain, or even the brain’s role in helping us to read human emotions in facial expressions (Panksepp & Gordon 2003). The tools of functional magnetic resonance imaging (fMRI), positron emission tomography, dense-array electroencephalograph technology, and the measurement of evoked potentials combined with the methods of psychoneuroimmunology offer exciting opportunities to link the occurrence of everyday social inequalities to brain function and physiologic reactions.

Exciting research that melds the study of social cognition with the techniques of brain mapping have begun to allow direct examination of the functional effects of social inequalities based on social exclusion (Eisenberger et al. 2003) interracial Black/White race contact responses (Baron & Banaji 2006Cunningham et al. 2004Eberhardt 2005Golby et al. 2001Lieberman et al. 2005Phelps et al. 20002004), and social pain (Brown et al. 2003Macdonald & Leary 2005) in brain function. These recent studies have expanded the opportunity to study the relationship between external events and internal brain processes as well as to elucidate the factors that make up the pathways of downstream health effects. In their examinations of how the brain processes social information during functional scans, researchers have shown that neural activity occurs in the brain structures that are directly responsible for activation of stress and the allostatic load responses. In particular, two brain structures, the amygdala and anterior cingulate cortex (ACC), show activation in response to social stresses (Baron & Banaji 2006Lieberman et al. 2005Macdonald & Leary 2005Phelps et al. 20002004). In addition to examining the role of these brain structures in response to social stresses, it is also useful to consider what contributions the processes of cognitive appraisal, self regulation, and social exclusion may play in the effects of race-based discrimination on the health of African Americans.

The Amygdala and Race Imaging

The amygdala plays a key role in the processing of emotions, including anger and fear. It is also the neural structure of the brain that is involved in forming and storing memories for emotional events. Historically, the amygdala was studied in relation to fear conditioning primarily in experiments that used rats. Recently, fMRI studies have demonstrated real-time effects in the amygdala when humans view fearful and threatening imagery (Delgado et al. 2006Phelps 2006Phelps et al. 2004). These studies show that as the amygdala responds to a fearful image, it initiates the stress response, in which the body recruits energy while it decides whether to fight or to take flight. Thus, the amygdala is key to understanding the process of allostatic load, or overactivation of the stress response.

In a series of recent studies, all from different labs, results indicate that for both White and Black participants, the viewing of Black faces, as compared with White faces, results in higher measurable levels of implicit brain activity in the amygdala (Cunningham et al. 2004Lieberman et al. 2005Phelps et al. 2003). This amygdala activation associated with race-related processing has been interpreted as representing fear conditioning to “culturally learned negative associations regarding African Americans” (Lieberman et al. 2005). Not so surprisingly, it also suggests that implicitly learned negative racial stereotypes about African Americans can be learned and encoded as a response by African Americans as well as White Americans (Olsson et al. 2005). Viewed from Massey’s model of racial stratification and poor health outcomes in African Americans, these findings suggest that implicitly learned fearful racial stereotypes may function to make the experience of living in race-segregated and poor neighborhoods a continuing source of chronic stress. This is not to say that racially/ethnically concentrated neighborhoods may not also be a source of providing social support, social connectedness, and a sense of belonging among African Americans (Cutrona et al. 2000). Both sets of conditions can occur simultaneously. But these laboratory findings hint that highly segregated, highly dense neighborhoods, plagued by high rates of crime and poverty, may create a social context in which chronic activation of fear responses leads to greater occurrence of the experience of allostatic load.

The Anterior Cingulate Cortex and Race

Another structure of the brain that is important to consider in examining real-time processes in race-based discrimination is the ACC. Recent studies have described the ACC as a discrepancy detector that monitors and regulates brain processes directed toward achieving goals. It is believed that the ACC functions at the subconscious level by being vigilant to conflicts to our goal attainments. In the case of conflict, the ACC engages conscious cognitive processes of the prefrontal cortex (PFC) to assist in either accommodating to or reducing the conflict (Eisenberger et al. 2003). Cognitive processes used by the ACC in its discrepancy-detector role include reasoning, decision making, motivation, and emotional regulation (Botvinick et al. 2004). These processes can facilitate an adaptive change to bodily states, such as altering heart rate, through mediation by the sympathetic nervous system (Critchley 2005Critchley et al. 200020012003). The PFC also has the ability to reduce activation of the ACC (thus reducing discrepancies in goals) as well as to increase activation of the ACC, resulting in hypervigilance. Put succinctly, the actual “function of the ACC is to integrate motivationally important information, with appropriate bodily responses” (Critchley et al. 2001). In this context, the ACC emerges as a brain structure with the ability to not only recruit cognitive function to reason and to assess race-based discrimination, but also to play a role in the mediation of aspects of the physiological downstream reactions to race-based discrimination.

Those who have studied discrepancy detection view the ACC as a critical monitoring system (Botvinick et al. 20012004Eisenberger et al. 2005). When the ACC experiences any inconsistencies between desired goals and impediments or conflicts, its activation acts as a neural alarm to the body that something has gone wrong (Botvinick et al. 20012004Braver et al. 2001Carter et al. 1998Eisenberger et al. 2005Weissman et al. 2003). The result is a greater demand on conscious cognitive processes with the goal to minimize the discrepancies in current actions so actions can once again lead to desired goals (Carver & Scheier 1990). As discrepancies resulting from goal conflicts are reduced, so too is activation in the ACC, quieting the alarm and returning the body to homeostasis.

In addition to activation issues with the ACC, Thayer & Friedman (2004) suggest that in a situation where a threat is ever-present, as is the case for possible experiences with race-based discrimination, inhibition of the limbic system by the prefrontal cortex PFC is also partially released. The result is a state of compromise by the brain that allows hypervigilance and perseverative thought to decrease heart rate variability and increase the allostatic load indicators of blood pressure and cortisol through the amygdala and HPA axis activation (Winters et al. 2000). Expectations of race-based discrimination might result in hypervigilance, which would then result in a greater tendency to perceive conflict discrepancies, in spite of behavior that to some may appear not to be overtly discriminatory.

A key topic in understanding the possible role of the ACC, and collaterally the PFC, in linking African Americans’ experiences with race-based discrimination and downstream health effects may be that of social exclusion. Social exclusion is a general term used by social policy makers and social scientists to refer both to the consequence of being excluded or marginalized from desired social groups as well as the processes by which this occurs (Macdonald & Leary 2005). Social exclusion may be a consequence of discrimination and prejudice, as well as a mechanism by which discrimination and prejudice can be enacted. Social exclusion is actually best thought of as a dynamic concept in which it is related to social processes that can lead to social isolation of specific groups and individuals when they are marginalized by organizations, groups, or institutions within society. For those who are socially excluded, there is the psychological experience of loss in both a sense of belonging to a desired group and denial of opportunity to participate in certain social, political, cultural, educational, or economical opportunities and rights (Tezanos 2001). For many, this description of social exclusion parallels that of discrimination, or social rejection. Underwood et al. (2004) find not only that social exclusion and social rejection are similar, but also that both create a common pathway in relationship to pain (Baumeister & Leary 1995). Indeed, it has been argued that “being excluded from social groups ranks among the most aversive of human experiences” (Labonte 2004).

In fMRI neuroimaging studies of social exclusion, Eisenberger et al. (2003) found that the anterior cingulate cortex acts as a “neural alarm system or conflict monitor” that is sensitive to the experiences of social pain when social exclusion occurs (Eisenberger & Lieberman 2004Macdonald & Leary 2005). Social pain is described as a unique form of aversive distress that is felt specifically when rejection or social exclusion occurs (Eisenberger & Lieberman 2004Macdonald & Leary 2005).

To the extent that experiences of race-based discrimination are perceived similarly to experiences of social exclusion, perceived discrimination too might share—at the level of brain functioning—properties similar to those of social exclusion. This may explain a second paradox in African American health: rates of psychological distress are typically higher as compared with rates for White Americans, but rates of many common, stress-sensitive major mental disorders such as major depression and most anxiety disorders are lower (MMWR 2004USDHHS 1999). Higher distress levels may reflect chronic activation of unpleasant feelings of anger, hyper-vigilance, or being on edge. Perceived racial discrimination, with its implied obstruction in access to both belonging to a group and access to social resources, may result in social pain. This may draw the body away from homeostasis and possibly result in the activation of stress-related allostatic responses.

Self-Regulation, Social Acceptance, and Cognitive Appraisal in Race-Based Discrimination

The brain is not a passive recipient of stimulation. Self-regulation and cognitive appraisal are processes that allow individuals to achieve and maintain personal and social goals, including social relationships (Lieberman 2007). Self-regulation has been proposed as indispensable for the maintenance of social acceptance (Baumeister et al. 2005Carver & Scheier 1981). Self-regulation refers to such functions as executive and cognitive control, emotion and affect regulation, and maintenance of motivational drive (Baumeister & Vohs 2004Beauregard et al. 2001Levesque et al. 2004Muraven et al. 1998Ochsner & Gross 2005Ownsworth et al. 2002Posner & Rothbart1998Ylvisaker & Feeney 2002). Self-regulation of emotion maps onto the structures of the amygdala, ACC, and PFC, and thus may be related to the processes of race-based discrimination. In response to social stressors, individuals self-regulate in complex ways that might strengthen social bonds (Higgins 1996Leary et al. 2006Williams et al. 2000Williams & Sommer 1997) or lead instead to increased levels of aggression, depression, and unhealthy behaviors such as tobacco smoking and alcohol and drug use or abuse. An examination of the role that cognitive appraisal and self-regulation play in race-based discrimination and health outcomes in African Americans may provide some useful insights into the pathways of the upstream/downstream discrimination and health relationship.

Self-regulation has been shown to increase the retention of social information about events surrounding an individual’s experience of social rejection (Gardner et al. 2000). For example, in an experiment examining the selective retention of socially relevant events, subjects experiencing social rejection had a greater recall of the events than did subjects who experienced social acceptance (Gardner et al. 2000). In addition, a main effect for negative-event recall was greater than for positive events. In particular, the negative aspects of social rejection are consolidated to memory for the individual as a source of potential future harm and avoidance. These findings raise interesting issues to consider in the dynamics of the cognitive appraisal process in race-based discrimination. For example, individuals who have been rejected as the result of perceived racial discrimination may be more likely to have a heightened surveillance for negative social cues that resemble race-based discrimination and social rejection in comparison with individuals who are commonly accepted.

The ability of the appraisal system to self-regulate emotional control can be achieved through the lateral PFC. But, Wheeler & Fiske (2005) have also found that the emotional response to race-related imagery can be altered at the level of the amygdala. For example, studies (Cunningham et al. 2004Lieberman et al. 2005Phelps et al. 2003) have demonstrated that presentation of Black faces as compared with White faces results in greater activation of the amygdala. This activation was thought to lie in a process in which simply viewing Black faces stimulated negative stereotypes and prejudicial amygdala activation to outgroup members. However, Wheeler & Fiske (2005) demonstrated that a differential response of the amygdala to White and Black faces could not be achieved by visual inspection alone. Instead, a face must be cognitively processed to a level at which it achieves some social relevance before differential amygdala activation occurs. This suggests that cognitive appraisal of race-based discrimination occurs at multiple levels in the brain. Indeed, the ACC in many ways acts as a social monitor by responding to stressors of social rejection (Eisenberger et al. 2003). If the processes that occur in the brain for race-based discrimination are the same or very similar to those documented in ACC activation in the study of Eisenberger et al. (2003), we would then speculate that the ACC plays an intermediary role in the process of cognitive appraisal as it directs the recruitment of higher cognitive and emotional processing in the actual appraisal process.

A puzzling dilemma is posed to African Americans with regard to self-regulation. The authors of self-regulation and social rejection studies have pointed to a role of self-regulation to achieve social goals and acceptance. But the challenge may be for African Americans to quiet a regulatory system that is stimulated toward hypervigilance. Race-based discrimination may exact a chronic toll on the self-regulatory system and shape cognitive appraisals in ways that have yet to be studied.

ncbi.nlm.nih.gov

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