Lecture 4 - Limbic System Flashcards
Critiques of limbic system
- The exact brain regions are not agreed on
- Limbic regions aren’t functionally or anatomically isolated in some special way from the rest of the brain
Autonomic nervous system 4 functions
Fighting
Fleeing
Feeding
F*cking
What does the ANS control
The viscera (non-skeletal muscle ex: heart, lungs)
2 main divisions of the ANS
Parasympathetic system
Sympathetic system
Role of parasympathetic system
Preserving energy (rest and digest)
Role of sympathetic system
Expending energy (fight or flight)
Hypothalamus what it is and role
Collection of nuclei with control over autonomic nervous system and hormone secretion (homeostatic needs)
How does the hypothalamus interact with the endocrine system
Through the pituitary gland
Parts of the limbic system
Hypothalamus
Hippocampus
Amygdala
Limbic cortex
Landmarks to find hippocampus
- Start at temporal lobe and go medial until you hit a bump
- If sagittal section you will see a long rod like structure right next to a ventricle (black hole empty space)
Functions of hippocampus
- Consolidation of memory
- Spatial memory
Hippocampus get input from where
Entorhinal cortex
Hippocampus sends output where
Through fimbria, fornix to mammillary bodies/hypothalamus
Hippocampal circuitry
Input from entorhinal cortex to dentate gyrus to CA3 to CA1 and then output from CA3 and CA1 to the fimbria then fornix then to mammillary bodies and hypothalamus
CA3
More contextual memory (context in which you learn something)
CA1
More specific objects that you are remembering
Neurogenesis
New cells are born in the dentate gyrus of the hippocampus throughtout life
Where else does neurogenesis happen
Olfactory bulb
What factors might promote neurogenesis in the hippocampus
Exercise, sleep, good diet
What factors might inhibit neurogenesis in the hippocampus
Age, chemical substances, stress
How could you test whether factors affect neurogenesis in animal models?
Label cells that are neurons, and cells that are newly born, and see if they overlap
How could you test whether factors affect neurogenesis in humans?
Exercisers vs non-exerciser study and see the difference in hippocampus size, pre-post hippocampus size after exercise
Study of hippocampus size
London taxi drivers have larger hippocampus – good spatial memory
Amygdala functions
- FEAR
- Rage and aggression
- Sexual behavior
- Learning/memory
- Attention
- Novelty detection
Basolateral nucleus
- Slower, cognitive
- Inputs from hippocampus, association cortex, sensory cortex/thalamus (processed & filtered sensory info)
Central nucleus
- Faster, automatic
- Lower-level sensory input from (from viscera and body)
Both basolateral and central nuclei
Controlled by medial prefrontal cortex (anterior cingulate)
Basolateral nucleus outputs
Outputs to medial prefrontal cortex (higher order cognition), association cortex, ventral striatum/nucleus accumbens (reward and decision making)
Central nucelus outputs
Outputs to autonomic nervous system and modulatory systems (systems that regulate neurotransmitters)
Limbic cortex
Cingulate gyrus
Korsakoff syndrome
- Caused by thiamine deficiency, most commonly in alcoholism
- Damage to mammillary bodies and limbic thalamus
- Symptoms: amnesia and confabulation (fake memories)
Toxoplasmosis
- Parasite that lives in cat guts
- Infects the amygdalae of rats and makes them unafraid of cats
- May have some effects in adult humans, dangerous to fetuses
