Emotion

Abstract

This chapter will present evidence to suggest that emotion is best defined, not as a single reaction, but as a process: Emotion involves multiple responses, organized according to temporal and spatial parameters. Thus, events that are positive/appetitive or aversive/threatening engage attention. They prompt information gathering, and do so more than other less motivationally relevant stimuli. Motive cues also occasion metabolic arousal, anticipatory responses that are oriented towards the engaging event, a mobilization of the organism that can lead to some action. Emotional processing can be compressed into fractions of a second or considerably extended in time. We suggest that neural networks underlying emotion include direct connections to the brain's primary motivational systems, appetitive and defensive. These neural circuits were laid down early in our evolutionary history, in primitive cortex, subcortex, and midbrain, to mediate behaviors basic to the survival of individuals and species. Unconditioned and conditioned appetitive and aversive stimuli activate these motivational circuits. They determine the general mobilization of the organism, the deployment of reflexive attentional, approach, and defensive behaviors, and mediate the formation of conditioned associations originally based on primary reinforcement.

Brain systems underlying encounter expectancy bias in spider phobia

“…The recruitment of fear systems mediating immediate and direct pursuit of defense in the service of survival might therefore be predicted to inhibit or overrule slower and longer lasting processes that are implicated in the integration of existing knowledge, expectancies, and other goals. Here, however, we found no indication whatsoever that alterations in phobia-related encounter expectancies are associated with increased activity in the amygdala or other structures constituting the fear circuit (Davis & Lang, 2003). This might be explained by the fact that the amygdala evaluates the general salience of an event (Davis & Whalen, 2001;Kawashima et al, 1999;Wager, Phan, Liberzon, & Taylor, 2003), but is not (or is less) dependent on more fine-grained situational factors such as focus of attention (e.g., Straube et al, 2006;Vuilleumier, Armony, Driver, & Dolan, 2001).…”

“…A similar activation pattern was observed in the lateral prefrontal cortex, occipital cortex, and right premotor cortex/ supplementary motor area (see Supplementary Figure 2 for details) the presentation of the pictures (animal presentation phase) in phobics versus controls. Phobics displayed massively increased activity in many brain areas, including the classic fear circuit (e.g., Davis & Lang, 2003), emotion regulation systems (e.g., Carlsson et al, 2004;Hermann et al, 2009), and attentional networks (e.g., Pourtois, Schwartz, Seghier, Lazeyras, & Vuilleumier, 2006), when they were shown pictures of spiders rather than snakes or birds. This pattern constitutes a substantial arousal response and reflects the significant emotional impact of spider stimuli on these participants.…”

“…Standard presentation paradigms, in which phobic or fearful individuals watched pictures or films-without simultaneous assessment of expectancies-showed that spider phobia correlates with enhanced activity of the fear circuit (e.g., Davis & Lang, 2003;LeDoux, 1996) and with reduced activity in emotion regulation networks (e.g., Carlsson et al, 2004;Hermann et al, 2009), including regions such as the insula, medial prefrontal cortex (mPFC), and lateral prefrontal cortex (lPFC). Carlsson et al (2004), for instance, found that conscious perception of animal phobia-related pictures led to selective activation in the amygdala, anterior insula, medial orbitofrontal cortex (mOFC), anterior cingulate cortex (ACC), and periaqueductal gray (see also Dilger et al, 2003;Rauch et al, 1995), activations that were not seen for evolutionary fear-relevant but non-phobogenic animals.…”

The neuropsychology of fear learning and fear regulation

“…The basolateral nucleus projects to several target areas including the central nucleus of the amygdala that then projects via the stria terminalis and the ventral amygdalofugal pathways to several output regions in the diencephalon and brain stem that mediate the autonomic and somatic signs of fear (see Davis and Lang, 2003). Lesions of the central nucleus of the amygdala block the expression of fear-potentiated startle and blockade of the glutamate receptors in the central nucleus of the amygdala via local infusion of a non-NMDA receptor antagonist have the same effect.…”

Adaptación eapañola del "International Affective Picture System" (IAPS). Tercera parte.

“…Estos sistemas motivacionales están integrados en circuitos neurales del cerebro y, posiblemente, están íntimamente relacionados con las estructuras cerebrales que regulan los sistemas somático y autónomo implicados en la atención y en la acción (ver Davis, 2000;Davis y Lang, 2003;Fanselow, 1994;LeDoux, 1996LeDoux, , 2000. Es por eso que, cuando alguno de estos sistemas se activa, se producen cambios a nivel cortical, autonómico y conductual que varían en cuanto a su intensidad.…”