The Human Amygdala: An Evolved System for Relevance Detection

“…themselves, consistent with the suggestion that the amygdala acts as a relevance detector that is sensitive to the motivational salience of a stimulus given the current needs, goals and values of the organism (Davis and Whalen, 2001; Sander et al., 2003; Pessoa, 2010; Cunningham and Brosch, 2012).”

“Thus, ourfindings provide further support for the concept that the amygdala is especially sensitive to varying intensities of salient social information, irrespective of valence (Sander et al., 2003).”

“…important for fast processing of visual stimuli, as compared to cortical regions, has been questioned by Pessoa and Adolphs (2010) who proposed its major role is coordination and integration of biologically significant information and modulation of response (see also Sander et al., 2003).”

“Overall, these findings are coherent with the relevance-detection framework (Pessoa & Adolphs, 2010; Purkis et al., 2011; Sander et al., 2003).”

“The amygdala is also implicated in a range of affective processes, including general detection of salience (Davis and Whalen, 2001; Sander et al., 2003; Kober et al., 2008), facial processing (Todorov et al., 2008), and experiencing fear (LeDoux, 2000).”

“Others have found that the activation of amygdala is modulated by the valence of faces and facial expressions [5,8,17], leading to the conclusion that the amygdala is as a “relevant detector” that serves to provide appraisal of face-related events [34].”

“Recent accounts propose that the perceived intentions and thus the self-relevance of emotional faces account for the frequently observed interaction of gaze and facial expressions on amygdala responses (Sander et al., 2003, 2007).”

“These findings have shifted the conceptualization of the amygdala from a threat detector to one associated with a more general function in accessing motivational relevance (for reviews, see Sander et al., 2003; Cunningham and Brosch, 2012).”

“Recent advances in neuroscience suggest that the role of the amygdala does not seem to be restricted to emotional stimuli but that this structure may represent a more general relevance detector for salient, personally and socially relevant, or novel stimuli (for reviews, see Armony, 2013; Jacobs et al., 2012; Sander e…”

“As it is perhaps the most important among our findings, the increased activation of left amygdala when reading about magical events deserves detailed discussion: left lateralization of the amygdala activation was also observed in other studies using linguistic material as stimuli [70], and can be attributed to left he…”

“More generally, it is thought to serve as a ‘relevance detector’ that alarms cognitive and sensory processing systems (Sander et al., 2003; Whalen et al., 2013).”

“Involvement of the amygdala in the neural response to fearful faces, but not to angry or sad faces has been suggested by some studies, but not by others.(61,62) Our study showed lateralization effects in the amygdala in the PCLO risk allele group, which may reflect a bias towards a more specific, sustained emotional r…”

“…and in patients with major depressive disorder (Dannlowski et al., 2008) The amygdala is a key structure of the ‘‘emotional brain’’ (LeDoux, 1996), and has been conceptualized as a relevance detector for socio-emotional signals that are highly relevant for an individual (Sander et al., 2003).”

“Classical views describing amygdala involvement in threat detection, fear conditioning, and the processing of negatively valenced emotional stimuli (LeDoux, 2000; Davis and Whalen, 2001) have recently been supplemented by accounts of amygdala function in the context of non-aversive events (Sander et al., 2003; Ball et…”

“The idea of the amygdala as a relevance detector (Sander et al., 2003) is based mainly on a plethora of fMRI experiments showing increased BOLD responses to relevant as opposed to non-relevant stimuli, where relevance includes, but is not limited to, emotional (positive or negative) arousal and motivational value (see…”

“As a potential self-relevancy detector (Sander et al., 2003; Adolphs, 2010) the AMY seems more involved through higher vigilance based on stimulus ambiguity (Whalen, 1998).”

“(2003), suggested amygdala to be a “relevance detector” responding primarily to stimuli which are of central importance to the organism and its wellbeing (Sander et al., 2003).”

“The human amygdala is nowadays typically understood to function as a relevance detector, responding more strongly to information that is relevant to the intentions and goals of a given person at a particular moment in time (Sander et al. 2003; Pessoa and Adolphs 2010).”

“…but also includes negative emotions other than fear, positive information, and even a priori nonvalenced stimuli (see, e.g., Bzdok, Laird, Zilles, Fox, & Eickhoff, in press; Cunningham & Brosch, 2012; Pessoa & Adol-phs, 2010; Sander, Grafman, & Zalla, 2003; Sergerie, Chochol, & Armony, 2008).”

“This is in agreementwith findings that amygdala involvement is not restricted to fear-related stimuli (Sander et al., 2003), linking value to threat and reward predicting stimuli (Murray, 2007) for relevance detection.”

“Self-referencing and emotion additionally have been linked together in the study of conditioned fear and emotional learning, and the processes by which a neutral stimulus acquires emotional salience are proposed to be facilitated when stimuli are self-relevant [18,19].”

“These latter studies focused on facial features, but, considering the amygdala’s more general role in detecting and responding to relevant events (Anderson and Phelps, 2001; Sander et al., 2003; Klinge et al., 2010), it is likely that such a process also occurs for more abstract stimuli that have been endowed with rel…”

“The amygdala is a structure that is part of the limbic system, associated with social behavior and emotion processing (Phelps and LeDoux, 2005), or more broadly with “relevance detection” (Sander et al., 2003).”

“…characterized in terms of intensity (Surguladze et al., 2003; Anders et al., 2004), salience (Liberzon et al., 2003; Anderson, 2005), relevance (Sander et al., 2003; Zald, 2003), meaningfulness (Phan et al., 2002; Sergerie et al., 2008), or disambiguation of potentially significant stimulation…”

“This dedicated knowledge memory system serve a fundamental aspect of social-cognitive functioning that might have evolved to deal with socially relevant information [47], since it allows making general prediction about people behaviours, when prior experience or on-line interaction are reduced.”

“In line with the idea of the amygdala as a salient stimuli detector (Sander et al., 2003), we replicated previous findings of quadratic responses to face trustworthiness (Said et al.”

“…of negative stimuli (valence hypothesis), of highly arousing stimuli (arousal hypothesis), or of stimuli appraised as relevant given the current individual’s goals, needs, and values (relevance hypothesis; for review, see Cunningham & Brosch, 2012; Sander, 2013; Sander, Grafman, & Zalla, 2003).”

“The notion that the amygdala is reserved for negative threatening information has been questioned, as it has been shown that the amygdala is not only involved in the detection of threats but also of positive rewarding stimuli (e.g., erotic stimuli 1 or food; Sander et al., 2003).”

“As an alternative explanation, we suggest that the development of a hypersensitivity to emotional facial expressions, irrespective of the specific emotional category, could represent an effective way to rapidly detect the presence of self-relevant threatening events in the surroundings (Sander et al., 2003).”

“neutral prosody) are processed differently, specifically in the amygdala (Sander et al., 2003; Ethofer et al., 2009; Wiethoff et al., 2009; Frühholz and Grandjean, 2013).”

“The amygdala may increase the organism’s vigilance by increasing neuronal responsiveness in sensory systems receiving amygdalar inputs [34].”

“Numerous neocortical regions are involved in non-executive salience detection [4,5,8] but an ancient subcortical structure, the amygdala, has more than any other part of the brain been implicated in automatically orientating attention to the most relevant stimuli [9–11].”

“In concordance with previous results from our lab on male immigrants [18] and our hypothes is, bilateral amygdala activation in both samples was observed, confirming the role of the amygdala as a 'relevance detector' [37].”

“However, considering the role of the amygdala in signifying biological or emotional significance (Sander et al., 2003), it is likely that this effect is specific to emotional stimuli.”

“…threat-related stimuli induce preferential emotional learning by offering an alternative theoretical framework based on appraisal theories of emotion (e.g., Sander et al., 2003, 2005), which holds that emotional learning is driven by a process of relevance detection that is not specific to threat.”

“The amygdala might act as a ‘relevance detector’ during observation of biologically relevant stimuli [46].”

“Based on research demonstrating that the amygdala is involved in the detection of and response toward threat (Davis and Whalen, 2001; Sander et al., 2003; Öhman, 2005; Davis et al., 2010), studies have investigated how amygdala structure and function is related to individual differences in conservatism (Kanai et al.”

“These hypotheses are predominantly evidenced by findings from human neuropsychological and neuroimaging work (see for extensive review, [219]; see also, [220,221]).”

“However, an alternative role for involvement of the amygdala is not as an automatic detector of emotions per se, but rather as a detector of relevant and salient stimuli, of which emotional expressions represent a subclass (Sander et al., 2003).”

“Thus, regardless that this sub-division was activated by unpleasant stimuli, the extent of activation for unpleasant effects highlights amygdala's role as a signaling detector that projects to cerebrum regions so as to initiate appropriate behavioral responses (Sander et al., 2003).”

“On a more general level, the amygdala can be conceptualized as a fastacting detector for relevance and significance latent in the environment (Pessoa and Adolphs, 2010; Sander et al., 2003).”

“Indeed, it was demonstrated that activity in the amygdala—functioning as a detector of biologically relevant stimuli [64]—was increased for rising SPL stimuli as compared to falling SPL stimuli during wakefulness [65].”

“This result is compatible with the relevance detector theory suggesting that the amygdala has an important role of evaluating relevant events (relevance detector theory - Sander et al., 2003).”

“…whereas the amygdala, which has long been implicated in assessing value (Baxter & Murray, 2002; Costafreda, Brammer, David, & Fu, 2008; Sander, Grafman, & Zalla, 2003), appears to detect the relative salience of face stimuli (Gerber et al., 2008; Gobbini & Haxby, 2007; Sander et al., 2003).”

“Sander, Grafman, and Zalla (2003) review evidence that a basic function of the amygdala is detection of those stimuli that are relevant for achieving of specific goals.”

“Thus, in reference to the observer (e.g. Sander et al., 2003; Northoff et al., 2006; Herbert et al., 2011), the personal relevance of an emotional facial expression may vary depending on who is the target of an emotion.”

“Regarding the amygdala’s role in emotion perception, the current hypothesis is that this structure detects salience, a general feature of emotion (for a discussion, see Sander et al., 2003; Armony, 2013; Pourtois et al., 2013), through reciprocal connections with the cortex (Amaral et al., 2003).”

“…that the amygdala also contributes to attentional, cognitive and appraisal functions or the processing of rewards and emotional states (Baxter & Murray 2002; LeDoux 2008; Sander et al. 2003), we hypothesized that this brain region participates in the modulation of opioid-mediated reward behaviour.”

“This suggests that such structures are tuned to the detection of events of emotional value irrespective of valence in the sensory environment [56,57].”

“It then responds to these events by influencing both current and future behaviour through modulation of other brain areas, such as the hippocampus, the fusiform gyrus and the superior temporal gyrus (for reviews, see Sander et al. 2003; Dolan 2002).”

“This pathway routes information through primary visual cortex and inferior temporal cortex (IT) to the amygdala and is important in the evaluation of the emotional salience of the information (Davis and Whalen, 2001; Pessoa et al., 2002; Sander et al., 2003).”

“Stimulus significance can e determined by stimulus features such as intensity or novelty, ut also by their emotional relevance, e.g. being capable to elicit n emotional response.”

“Nonetheless, the close link between emotion and relevance (Frijda, 1986; Sander et al., 2003; Smith and Pope, 1992) and the wellknown role of the dmPFC in self-relevant objects processing (Moran et al., 2006; Yang et al., 2014), suggest that the emotion-discrimination task may have favored the…”

“It has been proposed that the amygdala facilitates the detection of behaviorally relevant stimuli, which incorporates but is not limited to emotion [79, 80].”

“The current role of human amygdalae in relevance detection and value assessment, a role spanning multiple cognitive and sensory domains [111,112,137,139], and subsequent sensory modulation via dense connections with visual cortices [33,143], comprise an expansion of a system originally processing salient sensory (e.”

“the detection of relevance of memories by the amygdala and insular cortex [128], classification of positive and negative experiences.”