social cognition Flashcards
1. neural bases of social perception - Haxby model 2. neural bases of social behavior - Numan model & three ways of understanding others
objection recognition pathway
ventral stream: what pathway, V1 -> inferotemporal cortex
dorsal stream: where pathway, V1 -> postrior parietal cortex
Macaque face cells
cells for processing face identity are found in the inferior temporal cortex (IT)
cells for processing facial expression are found in the superior temporal sulcus (STS)
prosopagnosia lesion (ventral occipitotemporal cortex)
prosopagnosia: can’t recognize faces but can still for objects
specific gyrus: FFA
identity vs expression
STS: whether same or different (eye gaze)
FFA: recognize identity
Haxby Face Processing Model
check the slides
core system and extended system
amygdala and affective evaluation of sensory stimuli
check the slides for the model
Information from all of the sensory systems feeds into the basolateral amygdala;
The central nucleus of the amygdala orchestrates physiological and emotional responses to threatening stimuli
fearful face and amygdala
bilateral lesion of amygdala and dampens the ability to process fear
trustworthiness of faces
bilateral amygdala lesion patients rates face as trustworthy, opposite to the controls (b)
conscious and unconscious fear processing
Also consistent with the lesion studies, many functional neuroimaging studies have shown that there is an increase in blood flow to the amygdala when a subject looks at a face with a fearful expression. Interestingly, amygdala activation to fearful faces does not require conscious processing of the stimulus. In one experiment, either a fearful or a happy face was presented for 33 msec, followed by a neutral face for 167 msec. Subjects report only seeing the neutral face, but the amygdala shows stronger activation for the masked fearful compared with the masked happy face stimuli. This suggests that the amygdala receives sensory information by two different routes. In one route, visual information is relayed by the thalamus to primary visual cortex in the occipital lobe and is then further processed in the ventral temporal cortex before reaching the amygdala. This route is involved in the conscious processing of visual stimuli. The unconscious route would presumably bypass the cerebral cortex, and move from the thalamus directly to the amygdala.
the shape of the eye and fear in amygdala
Consistent with the eye tracking studies, the amygdala is particularly attuned to the shape of the eye whites in fearful expressions. In this experiment, subjects showed a stronger amygdala response to eye whites associated with fearful faces than eye whites associated with happy faces. Stimuli were again backward masked as in the previous study.
oxytocin and amygdala function
threatening face and scene activates amygdala, but oxytocin injection reduce the activity
amygdala activity increases if knowing people don’t want to cooperate, but oxytocin reduce the activity
summary of the first part
- Primate brains are specialized for vision, and primates recognize one another visually
- Humans process faces differently from other objects
- Cells in macaque inferotemporal cortex (IT) are specialized for processing face identity
- Humans process face identity in the right fusiform gyrus (FFA)
- FFA may be homologous with face-specific cortex in monkey IT
- Both monkeys and humans process dynamic aspects of faces in STS
- The amygdala is involved in detecting danger, threat or opportunity (salience)
- The amygdala is involved in recognizing both fear and untrustworthiness in faces, both of which may signal danger
- Sensory information from multiple modalities feeds into the basolateral nucleus of the amygdala
- When appropriate, the central nucleus of the amygdala acts through the hypothalamus and brainstem to orchestrate a physiological and emotional response to threatening stimuli
- The amygdala can process danger either unconsciously, bypassing the cortex, or consciously - Individuals vary with respect to how responsive their amygdala is to threatening stimuli
- OT attenuates the amygdala response to threatening faces and negative social interactions
- Targets of the mesolimbic DA system track the attractiveness of faces
components of rat maternal care
Nest building
Pup retrieval
Nursing
Grooming
rat maternal behavior
Males and nulliparous female rats avoid or even attack pups;
Post-partum female rats are promiscuously maternal immediately post-partum;
Virgin female rats avoid or even attack pups;
Intracerebroventricular (ICV) oxytocin elicits maternal behavior in virgin female rats primed with estrogen
approach-avoidance model of maternal behavior
check the slides
brain region involved in maternal care
medial preoptic area (MPOA) in hypothalamus
function of MPOA
activates approach system (NA) and inhibit avoidance system (OB/AOB)
lesion of OB/AOB “starts” maternal behavior
check the slide 44 for the model
hormonal influences on maternal behavior
OT and dopamine
mesolimbic DA system and approach
DA is released into NA during maternal behavior;
Lesions of VTA and NA disrupt maternal behavior;
The mesolimbic DA system is more active in rat mothers that lick and groom their offspring more frequently
OT in maternal care
Maternal NAcc response to own infant videos is positively correlated with plasma OT;
OT modulates maternal amygdala response to infant cries
CC outcomes
In our initial study on this topic, the areas shown here were more active following CC outcomes than after receiving the equivalent amount of money in a non-social task. Further, the activation in the ventral striatum is stronger for CC outcomes with human partners than for CC outcomes with computer partners.
Subjects who activated the caudate nucleus more strongly in response to mutual cooperation were more likely to persist with cooperation in the next round.
Collectively, these data suggested to us that mutual cooperation may be activating dopamine reward systems in the brain.
three systems for understanding others
- Mirror Neuron System (understanding actions and intentions)
- Emotional Empathy System (understanding feelings)
- Theory of Mind (understanding thoughts and beliefs)
mirror neurons in macaques
- STS codes the actions of others
- PF and F5 map the actions onto the motor repertoire of the observer
- F5 codes the goal of the action
4 Mirror neurons allow us to map the observed actions of others onto our own motor repertoire so that we can better understand the action and the intent behind it - The mapping is stronger when we have experience with the observed action
mirror neurons in humans
mother responding to pictures of children
emotional empathy system and the anterior insula
More generally, the insula is a visceral somatosensory cortex that tracks changes in the state of the viscera of the body. According to Damasio and others, the visceral responses represented in the anterior insula give rise to conscious “gut” feelings that bias decision-making.
one example of the emotional empathy system in human
image women with fMRI when they receive electric shock (green) or their male partner receive electric shock (red)
women scores higher on empathic concern scale with higher activity in anterior insula
define theory of mind
The ability to make inferences about the mental states of others, including what they know, believe and intend to do
theory of mind neuroimaging studies
- Stories with fictitious characters
- Comic strips with fictitious characters
- Interacting geometrical shapes
- Real social interactions that people are personally embedded in
brain areas activated during TOM studies
Dorsomedial Prefrontal Cortex
Posterior STS / TPJ
summary of the second part
- Rat maternal behavior depends on MPOA activation of the mesolimbic DA approach system and inhibition of the avoidance system that runs through the amygdala. Maternal behavior is facilitated by the actions of estrogen, oxytocin and prolactin on these neural systems.
- This same model may be relevant to human maternal behavior, as well as human prosocial behavior more generally.
- Human prosocial behavior additionally depends upon several cortical systems involved in understanding others
- The mirror neuron system is involved in understanding others actions, including facial expressions
- The anterior insula is involved in understanding other’s feelings
- DMPFC and TPJ are involved in understanding other’s knowledge and beliefs
summary of brain regions and their functions
STS/IF: understanding other’s actions and facial expressions
AI: understanding what others feel
DMPFC: understanding what others are thinking
Amy: fear, aversion,avoidance of others
VTA: motivation to approach and nurture/help others
OT: activate ventral striatum and inhibits Amy
LPFC (not discussed): emotion regulation and impulse control
