Lecture 14 - Neural Mechanisms Flashcards
Key regions in emotion regulation
Important to know that all brain areas work together; but specific brain areas are more looked at
- Orbital PFC and ventromedial PFC
- Dorsolateral PFC
•Planning function (ex: navigating)
- Amygdala (small but important in initial emotional response) and hippocampus (memory formation, and trauma)
- ACC (more integrated region; integrating brain regions responsible for effect of response and cognitive control)
All of these are part of the frontal limbic system
Prefrontal cortex - subdivisions
Dorsolateral
- cold processing
- planning, navigation
- Neutral information
- Executive functioning, cognitive processes
Orbitofrontal/Ventromedial
- hot processing
- deals with emotional information (emotional decisions)
- Ventromedial: affective functioning (rewards/motivation)
Amygdala
- One most widely studied areas in the field of emotion regulation
- Integrated centre of emotion
- Important in emotional learning/fear conditioning
- Highly connected with other brain regions, function depends on connection
Hippocampus
- Learning and memory
- Important in stress regulation
- Highly connected to the HPA axis
Anterior cingulate cortex
- Bridge b/w attention and emotion
- 2 subdivisions: affect (rostral, ventral) vs. cognitive (dorsal)
3 processes of emotion perception
1) identification of the emotional significance of a stimulus
2) production of affective state
3) regulation of the affective state
Bottom Up vs. Top Down Processing
- Bottom up: automatic, effortless, implicit processing of information
- Top down: slow, explicit form of processing of information “effortful” processing
Emotion Regulation in Depression - PFC
- Functional: Decreased activation in dorsal lateral “cognitive” area, increased activation in the ventromedial “affect” area
- Structural: Reduced volume in PFC, including OBFC, lower cortical thickness
Amygdala and depression
- depression related to increased activation in amygdala
Hippocampus and depression
- reduced volume (seen more with trauma - PTSD)
- Neuroplasticity: antidepressants seem to effect hippocampal structure and function
Bottom up and Top down in depression
- Bottom up: increased
- Top down: decreased
Increased bottom up processing and decreased top down control may underlie faulty cognitive regulation of emotions
Role of Serotonin
- Serotonin plays a role (among many other things) in cognition
- This includes memory, attention, and executive functioning
- Most of the experimental evidence for memory
Serotonin & amygdala activation -
fMRI paradigm:
Greater activation of amygdala in response to negative stimuli in carriers of SS or S/L genotype (healthy samples)
SSRIs and emotional processing
- SSRIs are effective in many individuals with depression
- Don’t work right away, takes couple weeks
- Why? Pharmacological mechanism: desensitization of certain receptors
Impact of SSRIs on emotional processing (STUDY)
A single dose of the SSRI, citalopram
(20 mg):
- Increased the recognition of happy facial expressions
- Increased attention to positive socially relevant stimuli
- Increased recognition of fear
- No change in mood
Repeated dose of SSRIs:
- Decreases recognition of fear
- Increases positive/affiliative behaviors
- No change in mood
