The Limbic System Flashcards
What is the limbic system?
A network of neurones that processes emotion and enables communication of structures involved in autonomic function with structures involved in awareness.
List the components of the limbic system.
1 - Cortex.
2 - Cingulate gyrus.
3 - Hippocampus.
4 - Hypothalamus.
5 - Anterior thalamic nuclei.
6 - Amygdala.
Where is the cingulate gyrus?
The cingulate gyrus is a curved fold that covers the corpus callosum.
Where is the amygdala?
List the component nuclei of the amygdala.
- The amygdala is close to the hippocampus in the frontal portion of the temporal lobe.
Component nuclei:
1 - Corticomedial nuclei.
2 - Central nucleus.
3 - Basolateral nuclei.
List 2 functions specific to the amygdala.
1 - The amygdala controls fear.
2 - The amygdala is a site of entry for sensory information, and therefore facilitates emotional memory if a stimulus has sufficiently strong emotional content.
What is the Papez circuit?
Describe the circuit.
How would a more modern revised circuit differ from the traditional Papez circuit?
The circuit formed by the components of the limbic system (amygdala not included as this was more recently discovered):
1 - The cingulate gyrus sends information to the hippocampus.
2 - The hippocampus sends information to the hypothalamus.
3 - The hypothalamus sends information to the anterior thalamic nuclei.
4 - The anterior thalamic nuclei sends information to the cingulate gyrus.
- The cingulate gyrus and cortex are freely able to communicate with each other.
- A more modern revised circuit would have the amygdala between the hippocampus and hypothalamus, where it acts as a site of entry for sensory information.
Which area of the cortex is thought to have the strongest influence on the limbic system of all areas of the cortex?
The prefrontal cortex.
With which structure does the limbic system communicate to elicit a behavioural response?
The periaqueductal grey area elicits a behavioural response.
What is the role of the hypothalamus in the limbic system?
The hypothalamus can elicit an autonomic response to stimuli that excite the limbic system (e.g. sweating and shitting yourself when you see a big lion).
What is the role of the cortex in the limbic system?
The cortex can elicit an emotional response to stimuli that excite the limbic system.
List the structures of the limbic system that control aggression.
With which emotion might aggression share a neural pathway?
1 - Amygdala.
2 - Hypothalamus.
- Aggression might share a neural pathway with fear.
List 5 conditions that are linked to dysfunction of the amygdala.
1 - Anxiety disorders.
2 - PTSD.
3 - Depression.
4 - Autism.
5 - Aggression.
Give an example of an experimental treatment for a condition relating to limbic system dysfunction.
Deep brain stimulation for depression.
