limbic system Flashcards
what is the limbic system - location wise
ring of cortical components surround subcortical nuclei and connecting paths
how old is the limbic system
Deepest part of the brain is the oldest part of the brain – this is where the limbic system is
olfactory system and the limbic system
smell makes you remember something (poem)
The olfactory system has massive inputs to the limbic system
Amygdala functions
in behavioral awareness and passion
(charge to drive)
Hippocampus functions
memory formation and retrieval
connects to other brain regions for memory storage and recall
much through entorhinal cortex
key thalamic nuclei with limbic connections
Mammillary body (of hypothalamus)
Anterior nucleus of thalamus
Medial dorsal nucleus of thalamus
overall Limbic system connections
lots of talk, and still under construction
Fornix limbic connection
from the mamillary body to the hippocampus (black)
Mammillothalamic track
full memeory and learning - emotion and drive
mamillary bodies to the anterior nucleus of the thalamus
Medial forebrain pathway
the major output pathway used by the post hypo and has pathways to the BS for the ANS and to the limbic system
Cingulate bundle
communication from the cingulate cortex to all other areas of the cortex
The cingulate has a lot input to the cortex about weighting behavior
Cingulate cortex functions
mood, thinking, moving and visual processing
these are all on different areas of the cortex
Cingulate cortex connects with what
the rest of the cerbral cortex
Motor sensory area of the cingulate cortex
role- making the decision to move
what are motor skills
voluntary, goal-directed, sequences of motor actions
limbic activity in preparation of a skilled movement
activity goes down
If you really know how to do a movement – you do not think a lot about it/decide to do it
when people become experts in their motor skill the activity become automatic
Papez circuit - function
important for episodic memory consolidation - Establishing the emotion sig of memory for survival
hypo role in papez circuit
The hypo has actions to change the phys of the body through the ANS - this change is seen because of emotion expressed
fornix - papez circuit
major pathway for processing cognition to emotions
Mammillo-thalamic tract - papez
- Emotion and physiology became conscious aware – I am aware of how I am feeling
Prefrontal path - papez
major pathway into the hippo, for memory info
emotional based learning
entrohinal cortex
Hypothalamus and brainstem nuclei do what for the limbic system
carry out the roles of weight decisions
Limbic function in BG loop
amygdala, hippocampus
Most of the input is to the ventral striatum (red arrows)
this is intergrateing limbic function with regulation of motivation, reward-based action and mood
Modulator in the limbic BG loop
ventral tegmental area (dope input to the striatum)
Dope driving the selection and energizing it
what is the ventral sriatum.
nucleus accumbens
would limbic drive for BG bee seen in early learning
no - this is based or reward therefore we need to know how to do the action before this
Goal directed behavior
something you expect to accomplish our have reward for
which mean we know how to do something and know how to respond
what is role of the The ventral striatum in the limbic BG path
integrates the limbic drive and cortical planning to facilitate goal directed behavior
what does the hippo do to the VS
Depolarizes neurons in the VS
high limbic drive leads to what
If the limbic drive it high – this leads to a quick strong well learned response – do it
Ventral tegmental area role
Dope input: regulating the balance between limbic drive and prefrontal cortex drive
what does ventral tegmental input allow you do to in the limbic BG
This allows who to shift your drive from an emotional quick action (limbic driven) to having the flexibility to choose a response strategy
the Prefrontal cortex drive allows for what kind of response
flexibility to choose the response strategy
in Schizophrenia what circuit is interrupted
hippocampal -PFC-Nuc Accumbens circuit and dopamine modulation disrupted
hippocampal -PFC-Nuc Accumbens circuit and dopamine modulation disrupted circuit interruption leads to what
lose cognitive flexibility
difficulty with switching responses in executive functions
when seeking or expecting reward - VTA dopaminergic input facilitates BLANK via what receptors
limbic drive
D1 receptors
VTA inputs when reward expectation is removed
D1 receptor firing is suppressed
allows PFC inputs to dominate, thus flexibility in behavioral response.
PFC deficits seen with Schizophrenia due to
D1 receptor activation - increased hippocampal input to Nuc Accumbens (limbic drive) facilitates dopamine release from VTA input,
attenuates PFC effects
