Subcortical structure (diencephalon, brainstem, RF)
-Ant. thalamic nuclei
All these structures and more have interconnections and play an important role in memory, emotions and behavior.
Its involved in cortical control of emotions and storage of memories.
It starts and ends in hippocampus.
1) Signals from hippocampus are transferred via fornix to mammilary bodies (hypothalamus)
2) Fibers run from mam. bodies to the anterior thalamic nuclei (mammilothalamic tract)
3) From thalamus, signals are transmitted to cingulate gyrus and via cingulum it goes to parahippocampal gyrus -> entorhinal cortex (28)
4) Fibers from entorhinal cortex will enter subiculum og hippocampus
-located in the temporal lobe
-huge impact on memories
-formation of new memories
-commisure of fownix is where the R+L fornix connects
-stimulation of amygdala can cause fear.
-patients with post-traumatic-stress disorder have large amygdala
-Amygdala communicates with other structures:
-amygdala-fugal pathway (to brainstem, thal, hypothal)
-stria terminalis (to hypothalamus) - direct pathway
-> autonomic response to emotions (inc. HR, BP)
-connection to hippocampus
-> create memories regarding a fearful experience
-> can explain why we remember scary, sad things
-connections to trigeminal nuclei: facial expression
-several connections to prefrontal area (behavior)
-less fear, more restless, emotional instability
-Prefrontal cortex (9,10,11,12)
*Phineas Gage got a metal rod penetrated through his prefrontal cortex -changed personality and behavior
Emotional feelings like euphora, pleasure.
When our body brings sensory info to our brain, the stimulus causes transmission via synapses and neurotransmitters.
When there is increased synaptic transmission, the synapses has the ability to strengthen.
So we say that synaptic plasticity is the ability of synapses to strengthen or weaken in response to increase or decrease in their activity.
Increased plasticity: stronger response to stimuli.
The act of glutamate on NMDA receptors are especially important.
Short term memory: look up phone number, remember and dial. We forget it within seconds.
-Hippocampus, mammilary bodies, ant&med thalamic ncl
Long term memory: permanent type of memory-days/years
-we see a phone number several times and it becomes a part of LTM, where info can be retrieved when needed.
-only 1% of conscious info is stored as LTM
LTM is divided into 2 parts
1) Declarative memory: events, things, people etc
2) Non-declarative memory: you recall specific skills or procedures. - how to use a pencil, ride a bike.
-if a person is given a list of items to remember and is tested if he could recall them in any given order.
2) Cued recall
-some numbers are paired with items and he is tested if he can recall the numbers with associated items.
3) Serie recall
-the person has the ability to recall the items in the correct order.