Bc things start out in the limbic system that send signals to other areas of the brain that then modify that behavior

-fibers cross talk and even the autonomic system is activated to modify the behavior

1. Hippocampus - key structure

2. amygdala- key structure

3. olfactory cortex

4. septal cortex - lying inf to corpus collosum

5. thalamus

***hypothalamus is NOT part of the limbic system but has a direct connection

• lying inferior to corpus collosum
• is the pleasure center of the brain
• responsible for secretion of acetylcholine  --> projects to hippocampus, amygdala, cerebral cortex

• lies inferior to the lateral ventricle
• functions:
• 1. controls autonomic function
• 2. emotion
• 3. endocrine function
• 4. homeostasis
• 5. motor function
• 6. regulates food and water intake
• 7. regulates sleep wake cycle

-responsible for taste

location: in lateral sulcus

• located just lateral to the optic nerve
• grey matter that surrounds the hippocampus
• important role in memory encoding and retrieval

• houses the amygdala
• located just lateral to the occulomotor N

=control of emotion, storehouse of fear

• provides sensory info -->initiates visceral, endocrine, motor response
• communicates with many brain regions to control breathing, motor function, autonomic response, release of hormones
• responds to emotionally charged events in memory
• ex. response of running is due to it's connection to the hippocampus
• ex. shutting down of emotion is due to connection with prefrontal cortex

• key limbic structure
• anterior and medial to hippocampus

• learning and declarative memory
• key limbic structure
• on the floor of the ventricle, next to temporal cortex...so damage to this area can affect memory
• 3 zones:
• 1. hippocampus proper - c shaped...where pyramidal cells are...project from fornix to septal area and hypothal
• 2. dentate gyrus - contains granule cells that receive hippocampus input and send to the pyramidal cells of hippo and subiculum
• 3. subiculum - axonal processes from other 2 zones come together here and project through fornix to anterior nucleus of thalamus

1. fornix - all info from hippocampus travels here
2. stria terminalis - associated with amygdala

• conveys info from hippocampus to septal nuclei and mamillary body (hypothalamus)
• is a fiber tract - has no cell bodies
• has 2 tracts that run parallel to one another and dont cross - runs under corpus collosum but above thalamus
• the fornix commisural fibers communicate between the 2 tracts
• anterior part = columns
• posterior part = crus
• * passes via mammilothalmic tract to get info to thalamus

• Fiber tract thtat conveys info from amygdala to septal area and hypothalamus
• runs lateral to the fornix
• * passes info to ventral amygdalo fugal pathway to get things to thalamus

=at the head of the caudate nucleus

• if info makes it here then decides if becomes a long term memory or a behavioral response
• info travels into the thalamus at - anterior nucleus of the dorsal thalamus --> then to cingulate gyrus and into hippocampus

• 2 types:
• 1. declarative = explicit facts and events and short term memory...hippo
• 2. nondeclarative = implicit/ procedural - like learning to ride a bike
• if damage hippocampus you can lose one type but ay still have the second

= neural circuit for emotion

• hippocampus subiculum to
• fornix to
• mamillary bodies to
• mammillothalmic tract to
• anterior nucleus of dorsal thalamus to
• cingulate gyrus to
• parahippocampal gyrus to
• entorhinal cortex to
• subculiculum

• how we make long term memory
• additive type of event of electrical and chemical signals
• must get past thalamus to be made
• independent of hypothalamus

• cannot recognize facial expressions, fear

lose ability to learn new info, make new memories

alzheimers - can remember past only

lose ability to recall remote events or previously learned facts

lose more long term memory

• disease of the limbic system - due to alcoholism, vit b1 def
• anterograde and retrograde amnesia
• confabulation - make things up due to gaps in memory
• conversation is meager
• lack of insight
• apathy

• disease of limbic system - temporal lobe + amygdala damage
• dec fear
• overeat + eat inappropriate objects
• visual agnosia
• get behavioral changes, OCD, inappropriate hypersexuality
• psychic blindness - can see fine but problem with info coming from occipital lobe to frontal lobe