Limbic Flashcards
What are the “classic” structures of the limbic system?
Hippocampus, amygdala, cingulate gyrus, fornix, and mammillary bodies.
What additional structures are often included in the limbic system?
Hypothalamus, anterior nucleus of the thalamus, frontal cortex, basal forebrain, septal nuclei, and nucleus accumbens.
What is the main function of the mesolimbic dopamine system?
Connects the limbic system to the nucleus accumbens, serving as the brain’s reward center.
What is the role of the hippocampus in memory?
It consolidates short-term memories into long-term memory.
What is the Papez circuit mnemonic and pathway?
Pa is Hipp For Mamm A NT C ause she’s a Good Hipp y
Pathway: Hippocampus → Fornix → Mammillary bodies → Anterior Nucleus of the Thalamus → Cingulate Gyrus
What happens when the Papez circuit is disrupted?
Amnesia occurs, but the amygdala is not part of this circuit.
What is Long-Term Potentiation (LTP) and why is it important?
It is the process of strengthening synaptic connections, necessary for learning and memory.
What molecular changes occur during LTP?
Increased Ca²⁺ influx, activation of CREB, and upregulation of AMPA & NMDA receptors.
What is the difference between declarative and non-declarative memory?
Declarative (explicit) memory includes facts & events. Non-declarative (implicit) memory includes skills & conditioning.
What brain regions store different types of memory?
Hippocampus → episodic & pattern recognition
Frontal Cortex → factual retrieval
Cerebellum → motor skills
Amygdala → emotional memories
What is retrograde amnesia?
Loss of old memories but ability to form new ones remains.
What is anterograde amnesia?
Inability to form new memories but past memories are intact.
What is Wernicke’s encephalopathy and how is it treated?
Acute thiamine (B1) deficiency affecting the mammillary bodies; reversible with early thiamine replacement.
What is Korsakoff syndrome?
Chronic alcohol-induced memory disorder with irreversible anterograde & retrograde amnesia, confabulation, and susceptibility to seizures.
How does amygdala dysfunction affect behavior?
It can cause fearlessness, impulsivity, risk-taking, and emotional dysregulation (seen in Klüver-Bucy syndrome).
What is the function of the amygdala?
It processes fear, emotions, and emotional memory.
How does overactivity of the amygdala contribute to psychiatric disorders?
It is linked to anxiety, PTSD, and phobias.
What is the connection between the amygdala and the hypothalamus?
The amygdala helps trigger the hypothalamic stress response.
What is a seizure?
A temporary disruption of brain function due to excessive neuronal activity.
What is status epilepticus?
A prolonged seizure without recovery between episodes, potentially life-threatening.
What is the most common type of focal seizure?
Temporal lobe (limbic) seizures, often affecting memory and emotions.
What are common causes of seizures?
Acute causes: Hypoglycemia, infections, trauma, alcohol withdrawal
Chronic causes: Epilepsy, brain tumors, neurodegenerative diseases
How does alcohol withdrawal contribute to seizures?
Chronic alcohol use lowers seizure threshold, making withdrawal a major risk factor.
What type of seizure is absence seizure?
A generalized seizure originating in the thalamus, characterized by a brief vacant stare.
What distinguishes epilepsy from acute seizures?
Epilepsy is a chronic disorder with recurrent unprovoked seizures, while acute seizures may be triggered by reversible causes.
