Negative emotion

amygdala function

detects salience and tags events as important for memory and behavior

amygdala and fear

not a dedicated fear center but involved in processing salient emotional information

salience

importance or relevance of a stimulus that drives attention and memory encoding

fear

emotional response to an immediate and present threat

anxiety

anticipation or prediction of a future threat

emotion vs arousal

emotion has valence while arousal is general physiological activation

arousal

level of neural and physiological activation that can scale with intensity and salience

stress

physiological state involving activation of systems like the HPA axis and cortisol release

stress vs emotion

stress is not an emotion but a physiological response often associated with emotion

valence

positive or negative quality of an emotional state

approach behavior

actions driven by positive valence toward a stimulus

avoidance behavior

actions driven by negative valence away from a stimulus

emotion function

drives approach or avoidance behavior for adaptive survival

hippocampus and amygdala

work together in memory formation where amygdala tags importance

amygdala role in memory

enhances encoding of emotionally salient events

arousal and memory

high arousal increases likelihood of strong memory formation

priming

prior activation of a system increases sensitivity to subsequent stimuli

interoception

sensing internal physiological states

interoception role

provides internal signals that contribute to emotional experience

amygdala high road

slower cortical pathway that processes sensory input before amygdala response

amygdala low road

fast subcortical pathway that allows rapid response to potential threats

fear conditioning

learning that a neutral stimulus predicts an aversive outcome

conditioned stimulus

previously neutral cue that predicts an outcome after learning

unconditioned stimulus

stimulus that naturally elicits a response without learning

associative learning

linking stimuli based on temporal and spatial pairing

HPA axis

hypothalamus pituitary adrenal axis controlling stress hormone release including cortisol

cortisol

hormone released during stress that increases arousal and supports survival responses

sympathetic activation

fight or flight response increasing physiological arousal

prefrontal cortex regulation

top down control that can modulate amygdala activity

vmPFC role

helps regulate emotional responses and inhibit excessive amygdala activation

intercalated cells

GABAergic cells that inhibit amygdala output

basolateral amygdala

input hub that integrates sensory and contextual information

central amygdala

output hub that coordinates physiological and behavioral responses

medial amygdala

processes social and hormonal information influencing emotional responses

networks vs centers

brain function emerges from interactions between regions rather than single localized centers

amygdala and addiction

interacts with reward circuits such as nucleus accumbens in motivation and reinforcement

amygdala dysfunction

can lead to altered fear