Lecture 1 Flashcards
Hormones do not cause behavior, what do they do?
Increase the probability of a behavior occurring
What percent of the brain is made up of glia?
90% of the brain is glia
How many neurons in the brain? How many connections do they make?
86 billion neurons each with 10,000 connections
How can you strengthen a synapse?
Increasing dendritic spines or receptor density
What three pathways are dopamine associated with?
Mesocortical
Mesolimbic
Nigrostriatal
What do drugs of abuse typically piggy back onto?
Dopamine
Nigrostriatal pathway
Active in maintaining normal motor behavior
Loss of DA is related to muscle rigidity
Mesolimbic pathway
Dopamine release causes feeling of reward and pleasure
Neurotransmitter system most affected by addictive drugs
What is a hormone?
Hormones are chemical messengers released from endocrine glands that travel through the bloodstream to influence the nervous system and regulate physiology and behavior of an organism
Where do hormones come from?
Hormones are produced by glands and secreted into the blood
Where do hormones go?
They travel in the blood to target tissues containing specific receptors for the hormone
What do hormones do?
By interacting with their receptors, hormones initiate biochemical events that can activate gene expression (via intracellular receptors) or induce fast, non-genomic effects (via membrane receptors)
Hypothalamus
Control of hormone secretions
Pineal gland
Reproductive maturation
Body rhythms
Anterior pituitary
Hormone secretion by thyroid, adrenal cortex and gonads
Growth
Posterior pituitary
Water balance
Salt balance
Thyroid
Growth and development
Metabolic rate
Adrenal cortex
Salt and carbohydrate metabolism
Inflammatory reactions
Adrenal medulla
Emotional arousal
Pancreas
Sugar metabolism
Gut
Digestion and appetite control
Gonads (ovaries/testes)
Body development
Maintenance of reproductive organs in adults
Neuronal communication
Electrochemical communication
Fast
Highly specific
Neurotransmitters are released over a short range (synapse)
Hormonal communication
Long range
Slow
Very widespread
Coordinates response across whole organism
Two advantages of global communication
- Developmental: coordinated transformation of all cells in an organism
- Coordination of a body’s response to an environmental trigger
How is hormone production regulated?
Negative feedback system
A hormone secreted from an endocrine gland travels where?
Travels through the blood stream to target tissue (including the brain)
Solubility of steroid hormones
Lipophilic (fat loving) and can pass through the phospholipid bilayer (BBB)
Where are steroid hormones produced?
De novo in the brain
What do areas with dense receptors suggest?
Higher sensitivity to that hormone
What gives you a unique receptor?
For every hormone, there are unique receptors in the brain
Hormone and receptor levels
There is the level of hormone and level of receptor
Hormone level can affect receptor level (up and down regulation)
Once a hormone binds to a receptor in a brain cell, what 3 things can it do?
- Might change membrane potential, making it easier or harder to start an action potential
- Could impact gene transcription, mechanism for increasing/decreasing receptor expression
- Change protein expression (eg: stimulate NT synthesis)
Hormones influence neurons which can influence what four behaviors?
- depression
- stress
- aggression
- memory
What are the six parts of the limbic system?
Amygdala Hippocampus Thalamus Hypothalamus VTA Nucleus accumbens
HPA
Stress response axis
De novo
Brain has all machinery to make hormones
Trilude brain
Used in 1950’s (NOT TRUE)
Part one: phylogenetic part of the brain, ancient part of the brain
-temp regulation, metabolism, blood glucose levels
-bottom region of model
Part two: limbic system
-expanded in vertebrates and mammals
-influences decision making going up to cortex
Odine’s curse
Lesion to midbrain region and you lose the capacity to do automatic breathing
You die of sleep deprivation
Amygdala
Fear, anxiety, aggression
Hippocampus
Turns off stress response
Should be responsible for regulating stress
What is the last part of the brain to mature?
Frontal cortex
What is the best predictor of how large frontal cortex in a species is?
The average size of their social group
Suggests that this part of the brain evolved for gossip and social intelligence and social behavior
Bidirectional flow
