HMB200H1 Lecture Notes - Lecture 7: Amygdala, Fosb, Caffeine
Document Summary
Lecture 7: rewards and drug abuse. Midbrain summary tectum: sensory of turns. Central gray (pag): defensive responses. Central grey and deep layers of the tectum are important for defensive responses: ducking away, fighting, freezing, running away. Approach turns: intermediate layers, moderate stimuli, crossed tectospinal path. Avoidance turns: deep layers, intense stimuli, uncrossed tectopontine path. Defensive responses: pag, glutamate stimuli, descending paths. Tectospinal path produces approach turns turning and foveation of visual stimuli. Just below this, in the pontine reticular formation: Dopamine activation rewards (limbic) Ascending pathways activate higher centers for complex evaluation of stimuli, surroundings and learned experiences. Cholinergic arousal system severe arousal effects. Facilitates tectum and fast eye movements. Effect: cortex gets activated by diffuse thalamic activation. All sensory pathways to the thalamus result in cortical activation of all primary cortical areas. By opening up the thalamic gates, the cholinergic arousal system results in widespread cortical arousal. Mesolimbic system: going from midbrain to limbic cortex and limbic accumbens.