Limbic System: Hippocampus, Amygdala, Memory & Behavior

What is the Limbic System?

A functional system of cortical and subcortical neurons involved with memory and behavior.

Where is the Limbic Lobe located?

On the medial surface of the cerebral hemisphere, surrounding the corpus callosum and rostral brainstem.

What are the two key functional structures of the Limbic System?

The hippocampus and the amygdala.

What role does the hippocampus play?

It is crucial for memory and learning.

What are the three parts of the hippocampus?

Dentate gyrus, hippocampus proper, and subiculum.

What is the Papez circuit?

A circuit involving the hippocampus that includes connections like the fornix and mammillothalamic tract.

What is anterograde amnesia?

A condition where a patient cannot remember events that occurred longer than a few minutes beforehand.

What can cause profound short-term memory loss?

Severe hypoxia leading to bilateral damage to the hippocampus.

What characterizes Alzheimer's Disease?

Progressive dementia with abnormalities in memory, cognition, orientation, and behavior.

What happens to neurons in Alzheimer's Disease?

There is a loss of neurons in the hippocampus and entorhinal area.

What is the function of the amygdala?

It plays a role in behavior and emotions, associating experiences with consequences.

Where is the amygdala located?

Below the uncus near the dorsomedial tip of the temporal lobe.

What is the major output of the amygdala?

The ventral amygdaloid path, which sends input to the hypothalamus and other areas.

What is the role of the accumbens nucleus?

It is associated with reward mechanisms and pleasure.

What is the significance of the septal nuclei?

They are involved in connections that affect emotional and behavioral responses.

What is the relationship between the orbitofrontal cortex and social behaviors?

The orbitofrontal cortex is associated with social behaviors and decision-making.

What is the function of the anterior cingulate gyrus?

It serves as an inhibitory control center, allowing for second thoughts about actions.

How does deep brain stimulation relate to the subcallosal part of the cingulate gyrus?

It is used as treatment in severe depression associated with feelings of sadness.

What sensory systems are connected to the limbic system?

Olfactory, optic, gustatory, and acoustic systems.

What is the impact of excessive drug use on the anterior cingulate gyrus?

It can damage the area, leading to altered inhibition and addiction.

What is the role of practice and repetition in memory?

They are key to both memory consolidation and learning.

What happens to behavior with bilateral dysfunction of the amygdala?

There can be a profound loss of fear and decreased emotional excitability.

What is the function of the cingulum in the hippocampal circuit?

It gathers sensory input and transmits it to the medial dorsal nucleus of the thalamus.

What is the relationship between the accumbens nucleus and psychostimulants?

The accumbens nucleus is related to euphoria associated with the use of psychostimulants.

What is the effect of the medial forebrain bundle stimulation?

It allows for pleasure phenomena, such as sexual feelings.