week 9 Flashcards
is emotion inborn?
Trait emotionality is moderately heritable (40-60%) (Bouchard & Loehlin, 2001).
Genetic variants associated with trait emotionality have small effect sizes (Sen et al., 2004).
Brain metabolic measures related to emotionality show no heritability (Glahn et al., 2007).
Specific genetic variants are linked to reward and threat processing in the brain (Nikolova et al., 2016).
Associations between genetics and emotionality may result from gene-environment interactions.
the limbic system
identified by early emotion scientists for emotion.
Collection of subcortical structures beneath cerebral cortex and above brain stem.
Components include thalamus, hypothalamus, hippocampus, basal ganglia.
Cortical structures like cingulate cortex, insular cortex, and orbitofrontal cortex may be part of the limbic system.
Disagreement exists on the exact components of the limbic structure (Gazzaniga et al.).
the amygdala
-linked to emotions; injuries lead to reduced emotional responses.
Human studies confirm
- key role in fear conditioning.
-Amygdala functions in fear circuits: detects threat unconsciously, regulates responses, and signals cognitive systems for conscious fear.
the low and high roads to fear
LeDoux (1996) identifies two pathways to the amygdala: “quick and dirty” low road, and “slow but accurate” high road.
The low road bypasses cortical processing, activating the amygdala in 12 ms.
Dual process allows rapid, unconscious reactions before conscious fear.
the amygdala and HPA axis
detects threat, activating HPA axis.
Indirectly stimulates hypothalamus to release CRF.
CRF prompts pituitary to release ACTH into bloodstream.
ACTH triggers adrenal gland to produce cortisol.
Elevated blood cortisol levels respond to threat.
the survival circuits
LeDoux (2012): Renames amygdala circuits as “survival circuits.”
Acknowledges amygdala’s role in physiological threat responses, deeming it less crucial for subjective feelings.
Evidence: Amygdala stimulation elicits physiological, not subjective, responses.
Amygdala lesion patients can consciously report emotional experiences, including fear.
the amygdala and mental disorders
Anxiety disorders linked to heightened amygdala reactivity (Janak & Tye, 2015).
Applies to panic disorder, social phobias, PTSD, and GAD.
Increased amygdala activity triggers hormone elevation.
Anxious individuals need more PFC activity to suppress unpleasant emotions.
Similar amygdala hyperreactivity and reduced PFC activity seen in depressive disorders.
what about pleasure and reward
Brain’s reward system has three components: Liking, Wanting, Learning.
Mesocorticolimbic dopaminergic system, VTA, NAc, and OFC, is the primary reward circuit (Wanting).
crucial for the brain’s reward processes (Berridge & Kringelbach, 2015).
the role of amygdala in reward processing
Amygdala lesions impair reward-based behavior, affecting responses to changing cues (Janak & Tye, 2015).
encodes stimulus valence, with neurons responding to fear, reward, or both, proportionate to ANS activation (Sangha et al., 2013).
Orbitofrontal cortex tightly linked to amygdala, integrates inner and outer worlds (Adolphs, 2002).
Recent studies show orbitofrontal cortex represents reward value; lesions impair decision making when rewards cease (Rolls et al., 2020).
brain network perspective on emotion
Recent neuroscientific evidence favors a network perspective over a modular view of brain function.
Pessoa (2014) highlights pluripotency and degeneracy—regions participate in many functions and vice versa.
Brain processes are distributed and parallel, not sequential and hierarchical (Goldman-Rakic, 1988).
Extensive connectivity exists between cortical areas, subcortical-cortical areas, and subcortical regions.
features of brain networks
overlapping regions, with specific areas belonging to multiple networks.
Processes in a brain region aren’t fixed to a particular mental function.
McIntosh (2000) suggests a region’s network affiliation is dynamically determined by interactions at a given time, known as neural context.
Example: Cue indicating reward possibility increases cortical-subcortical functional connections (Kinnison et al., 2012).
emotion-related brain network features
Neuroimaging data shows emotion-associated neural systems spanning cortical and subcortical regions (Kragel & LaBar, 2016).
Emotional processing increases overall functional connections.
In the cortex, reward enhances connectivity, while threat decreases it (Pessoa & McMenamin, 2017).
Stronger signal correlations in the salience network link to stronger negative affect (Hermans et al., 2011).
Intensively studied networks: Salience (attention orientation), Executive control (goal-oriented), Default (task-negative, associated with memory and internal thought).
changes in network organisation over time
Study (McMenamin et al., 2014): Participants anticipated threat or safety for 60 seconds.
Threat initially increased salience network communication, reduced executive control network facilitation.
Intermediate period: Threat decreased salience network efficiency, increased amygdala involvement in inter-network communication.
evidence of cultural effects on emotion
Boiger (2013) cross-cultural study on anger and shame appraisals, action tendencies, and intensity.
Japanese anger type (55%): Nodding, smiling, rumination; American type (43%): Blaming, direct expression.
Uchida et al. (2009): Japanese emotions between people, American emotions within people.
Olympic athlete interviews: Japanese use more emotion words; Japanese infer more emotion in team context, Americans in solitary.
Chentsova-Dutton and Tsai (2010): Priming with individual or family self influences emotion intensity.
European Americans link emotions to individual self; Asian Americans link emotions to family and relationships.
differences in neurobiological substrates
fMRI study (Immordino-Yang et al., 2014): Chinese linked feeling strength to ventral anterior insula, European Americans to dorsal anterior insula.
Bicultural East-Asian Americans showed an intermediate pattern with equal ventral and dorsal anterior insula activation.
