Neuroscience test 3

• Reticular Activating System 
• Involved in sensory intake and encoding 
• RAS decides what goes to the cortex (consciousness)
• Activates in response to vision, hearing, touch, and taste (not smell)

• Reticular formation: Arousal states
• Pons: Arousal states and sensory input
• Thalamus: Sensory information

• RAS takes sensory input and gives it to thalamus
• Thalamus distributes everything to the proper brain regions

• Amygdala helps decide if things are meaningful/relevant enough to go to cortex
• After amygdala and RAS: information must be emotionally arousing enough to go to consciousness (too little or too much, goes back to unconscious)

• Control: positive emotions
• Exp.: negative emotions
• Emotions were induced by showing participants either happy or angry faces before giving them a list of words to memorize and recall
• Results: learning was better in happy face condition than angry face condition
• Happy faces: greater cortex activation, fMRI showed different activity in happy face group
• Angry faces: lower cortex activity
• Found that learning is better when it reaches conscious awareness

• PFC 
• Nucleus Accumbens (NAcc): motivation and goal directed behavior
• Ventral Tegmental Area (VTA): dopamine production area

• Amygdala provides emotional context (good vs bad)
• Hippocampus wants to send information to MTL to remember things
• If something is bad, and there is not enough dopamine, DPR will not activate 
• Lack of dopamine tells hippocampus to either forget the experience or remember it as bad 
• Sometimes the PFC adds conscious awareness, but sometimes this process is unconscious

• Can help judge choices
• Dopamine release increases when first making a choice. If the choice was good the dopamine goes up, bad choice dopamine goes down
• Important to get feedback and constructive comments quickly to fix mistakes and get dopamine reward

• Pruning- refinement in neural connections, occurs in learning circuits
• Addition/subtraction of myelin-Less common, speeds up/slows down signal 
• Strengthening/weakening pf synaptic connections- add more neurotransmitters/receptors, or take away if weakening

• have features that improve learning and reward pathway
• Uses dopamine pathway 
• Usually have right level of: challenge, instant feedback, stress, emotions

• monkeys
• lesioning the amygdala resulted in emotional blunting 
• Klucer-Bucy syndrome- emotional processing compromised

• Amygdala damage/lesions cause participants to no longer learn fear 
• Used GSR- no measure if you lack amygdala function

• Images: Snakes/spiders-fear 
• Flowers/mushrooms-no fear
• Participants were shown consecutive images, some they had seen previously and some they had not 
• Participants has to push button when they saw a picture they had been previously shown 
• Faster at pushing button for the fear images than non fear 

• Evidence of two brain circuits related to visual detection: 
• Fast path: thalamus --> amygdala 
• Slow path: thalamus --> PFC

• Participants only shown snakes and spiders 
• Images shown subliminally (10 ms presentations) 
• GSR measured higher when image of snakes/spiders on screen, even though the participant did not consciously see them 

Results: fear processing happens subliminally 

Arachophobes had strong GSR with spiders than snakes, vice versa

Processing/interpreting pain and taste 

(taste aversion and disgust)

• 1. Interpreting value 
• How much something is worth to you in context 

• 2. Medial region
• Something being pleasant or desirable 

• 3. Lateral region
• Unpleasant or undesirable 

Study: peoples reactions to wine was based off price. People rated expensive wines as more desirable

• 1. Value of a response 
• What you do next, and will it result in punishment or reward

2. thalamus sends signal to anterior cingulate (pain signal)

• 1. Reward pathway 
• Emotional attachment/detachment to rewards 

2. Dorsal region-sensorimotor processing related to habits or forming habits 

3. Ventral region-ties emotional habit formation/social interactions/monetary value (emotional processing)

• amygdala 
• insula

• Also:
• orbiotfrontal cortex
• PFC

• Social functioning decreases
• Ability to feel embarrassment, empathy, guilt decreases

• Participants asked to respond to hypothetical scenarios:
• Trolley
• Foot bridge
• Lifeboat
• Hospital

• Results: 
• Trolley-most people would pull the lever to save the 5 people 

Lifeboat/footbridge-divided on what to do 

Hospital-almost no one said they would sacrifice one to save 5

• The more physically active in the scenario the participant is, the less likely they are to take action
• Different emotional responses in different areas of the brain

Damage to PFC, cingulate, amygdala changes judgement

People with these damages cannot reason normally/would see all moral dilemmas as the same

• Damage to PFC decreases decision making 
• Increases impulsive behaviors
• Decreases emotions

• Railroad spike through the head 
• Complete lack of emotions and self report feelings of pleasure 
• Rationality impaired/made bad decisions

This tells us that emotions and logical thinking go together

• Normal subjects and those with PFC damage
• Told that if they were given money they could split it with the others in their group or keep it all for themselves
• Normal subjects-majority shared 
• PFC patients-no sharing

• Normal participants and PFC patients 
• Given money and told that they could keep all the money or share some with the trustee
• If they gave to the trustee, it would triple in value and the trustee would give you a portion of it back 
• PFC damage-would not share 
• Normal participants-split the money

Results: PFC leads to a lack of trust, whereas normal participants trusted

• Harder to learn when you are scared-being called on/making mistakes can cause fear
• Yelling'shaming decreases amount of information being retained in the cortex
• Gorup work can make people more comfortable 
• Have to perk students interest, but not too much or they will not remember information