Limbic system Flashcards
What is the overreaching function of the limbic system?
Assign value to emotions or sensory events
How many layers is the hippocampal formation?
3
What are the 3 layers of the hippocampal formation?
- Dentate gyrus
- Hippocampus proper
- Subiculum
What is the name of the circuit that predates the modern concept of the limbic system?
Papez circuit
What is the papez circuit?
- Cinguate gyrus
- Hippocampus
- Fornix
- Hypothalamus - Mamillary bodies
- Thalamus
- Cortex
What is the function of the hippocampal formation?
- Formation of new memories and learning
What results from removal of the hippocampal formation?
Anterograde amnesia
What is anterograde amnesia?
Profound loss of recent or short-term memory and the ability to learn
What is retrograde amnesia?
Loss of memories from before the date of injury
Where is the amygdaloid nucleus located?
Deep to the uncus
What is the major afferent modality to the amygdaloid?
Smell
What is the major function of the amygdaloid?
- Programs appropriate behavioral/ emotional responses
- Puts affective value on stimuli
What happened in animals when the amygdaloid was stimulated?
Became more aggressive
What happening in animals when the amygdala was removed?
- Indifferent to stimuli that would have caused fear or sexual responses
What are the 3 functions of the central nuclei of the amygdala?
- Mediate emotional response
- Regulate autonomic nervous system
- Shape responses to emotional stimuli
What nuclei of the amygdala are the major division that attach emotional significance to stimuli?
- Basolateral nuclei
What 3 structures do the basolateral nuclei of the amygdala project to?
- Frontal lobe
- Thalamus
- Temporal lobe
What is the function of the cortical nuclei of the amygdala?
- Perception of smell
- Behavioral link to smell
What occurs when the septal region of the amygdala is stimulated in conscious patients?
Feelings of:
- Pleasure
- Optimism
- Euphoria
- Happiness
What centers are found in the septal region?
Orgasm centers
What structure does the septal region of the amygdala connect with in the reward system?
hypothalamus
What is the main projection of the septal region?
Reticular formation of the brain stem
What 2 structures does the cingulate gyrus connect?
The hippocampus and thalamus
What is the function of the anterior cingulate cortex in each of the following anatomic areas:
- Anterior
- Posterior
- Dorsal
- Ventral
- Anterior: Executive
- Posterior: Evaluative
- Dorsal: Cognitive
- Ventral: Emotional
How is the anterior cingulate cortex related to learning?
- Helps focus when effort is needed to learn: Assists in: - Error detection - Anticipation of tasks - Motivation - Modulation of emotional responses
