lecture 6 - memory systems

What is a cross-sectional study?

A study that examines different groups of people at one point in time to compare variables or characteristics between them.

What is a longitudinal study?

A study that follows the same individuals over time to observe changes and developments in the measured variables.

What is egocentric space?

A spatial frame of reference centered on the individual.

What is allocentric space?

A spatial frame of reference based on landmarks in the external world.

Define ischemia.

Restricted blood flow to tissue, often causing cell damage or death due to lack of oxygen and nutrients.

Who was patient H.M. and what was his condition?

Had both temporal lobes (including the hippocampus) surgically removed; struggled to form new spatial representations and memories.

How did patient H.M. perform on the Rey-Osterreith figure test?

Showed poor performance, indicating impaired spatial memory.

What is the Rey-Osterreith figure test used for?

To assess visuospatial constructional ability and visual memory.

Who was patient R.B. and what was his condition?

Had ischemic damage to the hippocampus, resulting in poor performance on the Rey-Osterreith figure.

Who was patient N.A. and what brain damage did he have?

Damage to the diencephalon—specifically the mediodorsal thalamus and mammillary bodies—causing diencephalic amnesia.

Define diencephalic amnesia.

Memory loss due to diencephalon damage (thalamus or mammillary bodies), affecting both anterograde and retrograde memory.

What is Wernicke-Korsakoff syndrome?

A neuropsychiatric disorder from thiamine (vitamin B1) deficiency, marked by confusion, confabulation, and severe memory impairment, often with diencephalic damage.

What causes Wernicke-Korsakoff syndrome?

Thiamine (vitamin B1) deficiency, often associated with chronic alcohol use, leading to brain and nervous system damage.

What is piloting in navigation?

Using external landmarks to determine position and direction.

What is the parahippocampal gyrus and its function?

A cortical area surrounding the hippocampus that supports spatial scene recognition and context processing.

When does the parahippocampal gyrus show strong activation?

When viewing navigationally relevant landmarks (e.g., at a decision point to turn left or right).

What is the primary function of the hippocampus?

Formation and retrieval of spatial and declarative memories; essential for spatial navigation.

What is the rhinal cortex and its role in memory?

Relays sensory and spatial information to the hippocampus to support memory formation.

What is the limbic system and its role in memory?

A network including the hippocampus and associated structures that processes spatial memory and navigation.

How is the hippocampal-diencephalic memory system related to the limbic system?

It is part of the limbic system and supports memory integration.

What are place cells?

Neurons in the hippocampus that fire when the animal is in a specific location within its environment.

Where are place cells found?

In the hippocampus.

What did studies of London taxi drivers reveal about the hippocampus?

They had a larger posterior hippocampal area, with hippocampal volume correlating with years of taxi-driving experience.

What are head direction cells?

Neurons that fire when the animal’s head points in a specific direction—functioning as an internal compass.

Where are head direction cells located?

In regions adjacent to the hippocampus, such as the post-subiculum and entorhinal cortex.

What are grid cells?

Neurons in the entorhinal cortex that fire at multiple spatial locations, forming a grid-like pattern that helps encode spatial navigation and distance.