PSY Learning 21/9 - Chapter 2

Flashcards reviewing key concepts from the lecture on the limbic system, long-term memory circuits, cortical lobes, comparative neuroanatomy, and neuronal structures.

What are the two main limbic system structures focused on in Chapter 1?

The left and right hippocampus, and the left and right amygdala.

What does the word "hippocampus" mean and where does its name originate?

It is named after the Greek word for "seahorse," referenced in relation to Poseidon's seahorses in the Odyssey movie.

Where are the hippocampi located in the human brain?

They are located about an inch and a half inside the brain, right at the top of the ears.

What does the word "amygdala" mean in Latin, and what are its physical dimensions?

"Amygdala" is Latin for "almond," and each amygdala is roughly the size and shape of an almond.

What primary function does the amygdala serve in processing emotional stimuli?

It acts as the brain's "alarm bell" by registering fear-inducing and threatening stimuli to trigger fight-or-flight responses.

What distinct contributions do the hippocampus, mammillary bodies, and amygdala make to long-term memory?

The hippocampus lays down the factual information, the mammillary bodies add a timeline, and the amygdala adds the emotional tone or component.

Which two neurotransmitters experience huge surges driven by the amygdala during a fight-or-flight response?

Epinephrine (acting primarily in the body) and norepinephrine (acting primarily in the brain).

According to the lecture, how does the amygdala assist in social interactions?

It helps read people's social intent through nonverbal cues like body language, tone of voice, physical proximity, and foot/body orientation.

How does retrieving a memory affect its original state in the brain?

Retrieving a memory causes the hippocampus to re-encode it upon saving, which can introduce small changes over time and lead to false memories.

What is the most common first symptom of Alzheimer's disease, and why?

Memory issues, because the temporal lobes and hippocampus are destroyed first by the disease process.

What are the six components of the Papez circuit in order of processing input to output?

Input travels from the cingulate cortex through parahippocampal tissue and entorhinal cortex to the hippocampus; output travels via the fornix to the mammillary bodies of the hypothalamus, up to the anterior nucleus of the thalamus, and back to the cingulate.

What role does the anterior nucleus of the thalamus play in memory processing?

It is responsible for memory consolidation, allowing new long-term memories to solidify.

During which phase of sleep does memory consolidation primarily occur?

REM sleep.

What percentage of people with dementia have Alzheimer's disease?

Approximately $70\%$ of people with dementia have Alzheimer's disease, out of about $60$ diagnosable dementias.

What is the second most common symptom of Alzheimer's disease mentioned in the lecture?

The inability to name an object, caused by the breakdown of organizational schema files in the temporal lobes.

What is the primary function of the corpus callosum?

It is a thick strip of myelinated white matter that connects the left and right cerebral hemispheres, allowing them to communicate with each other.

What is the origin of the name for the front part of the corpus callosum, known as the "genu"?

"Genu" is Latin for "bent knee" (as in genuflect), named because the structure resembles a bent knee.

What structural brain differences are associated with ADHD in the studies mentioned?

A smaller corpus callosum, a smaller right basal ganglia with reduced blood flow, and a smaller right prefrontal area.

Approximately how much of the cerebral cortex is made up of the frontal lobes?

About one-third ($\frac{1}{3}$) of cortical tissue.

What cognitive functions are governed by the prefrontal cortex?

Executive functions, including attention, problem-solving, organizing, sequencing, executing tasks, and short-term/working memory.

What are "schemas" in the context of memory storage in the temporal lobes?

Mental organizational frameworks or category files used to organize and identify concepts, objects, and experiences.

Why does a dolphin's brain have a proportionately larger cerebellum than a human brain?

Because dolphins are constantly in motion and shut down only one brain hemisphere at a time to sleep while continuing to swim.

What are the four main components of a neuron?

The cell body (soma), dendrites, the axon, and axon terminals (synaptic terminals).

What function do dendrites perform?

They receive neurotransmitter messages from neighboring neurons using receptor cells located along their branching edges.

How many potential connections between neurons can exist in the human brain?

One quadrillion ($1 \times 10^{15}$) potential connections.

What is myelin, and how does it affect signal transmission speed along an axon?

A fatty fibrous substance made of glial cells that wraps around axons, increasing chemical/electrical communication speed from $2\,\text{mph}$ up to $200\,\text{mph}$.

What are the gaps in the myelin sheath called, and what is their function?

Nodes of Ranvier, which allow the electrical impulse to jump along the axon to speed up signal transmission.

How long does the complete myelination process of the prefrontal cortex take in humans?

Approximately $20$ to $25$ years (and up to $30$ years according to some studies).

What date was scheduled for the upcoming exam?

Wednesday, September 30.