Memory & Learning Flashcards

According to the Atkinson & Shiffrin (1968) model, what are the three main stages of human memory?

Sensory memory: Initial processing of sensory information.

Working memory: Information maintained through rehearsal and retention.

Long-term memory: Information stored for long-term use.

Note: Information can be lost or forgotten at any of these stages.

Working memory (WM) can be defined as a...

the ability to maintain and perform operations on internal representations of information that is no longer available in the environment. It involves keeping information in an "online-state".

Compare the Goldman-Rakic prefrontal model and the "Sensory Copy" model of working memory storage.

Prefrontal: Information is processed in sensory areas and then fed forward to the prefrontal cortex, where cells maintain the info during the delay period.

Sensory copy: Primary sensory areas that initially encode the stimuli continue to maintain a copy of that information during the WM period.

How do population-decoding methods like MVPA (Multivariate Pattern Analysis) differ from traditional mean activity analysis?

Traditional methods look at a single aggregate measure (mean activity), which may not show differences between stimuli. MVPA looks at the pattern of activity across multiple voxels (ensemble activity), which can contain specific information; for example,  about the contents of working memory even when mean levels do not differ.

What is the difference between a stationary code and a dynamic code in population coding?

Stationary code: The same pattern of neural activity across a population of neurons is seen at all points in time, creating a point in multidimensional space.

Dynamic code: A different pattern of neural activity is present at each point in time, creating a trajectory in multidimensional space.

Name the two main branches of long-term memory (LTM) and the brain regions associated with them.

Declarative (Explicit): Facts and Events; involves the Hippocampus, Medial Temporal Lobe, and Diencephalon.

Nondeclarative (Implicit): Skills and Habits (Striatum/Motor Cortex/Cerebellum), Priming (Neocortex), and Basic Associative Learning (Amygdala/Cerebellum).

What is the difference between episodic and semantic memory?

Episodic memory is about events and semantic memory is about facts (episodic is "remembering", semantic is "knowing"). Both are part of the declarative and explicit memory systems in the taxonomy of memory systems, separate from non-declarative or implicit memory systems.

Fill in the blanks by using the words listed below.

The _______ is a critical structure for the formation of _______ . These traces represent the 'Events' category within the _________ long-term memory system. Anatomically, sensory input reaches the hippocampus from the _________  via the _________ pathway, primarily targeting the granule cells of the _________ 
 

hippocampus

episodic memory traces

declarative (explicit) 

entorhinal cortex 

perforant

dentate gyrus

The hippocampus is a critical structure for the formation of episodic memory traces. These traces represent the 'Events' category within the declarative (explicit) long-term memory system. Anatomically, sensory input reaches the hippocampus from the entorhinal cortex via the perforant pathway, primarily targeting the granule cells of the dentate gyrus.

True or False? Partial activation of the neocortical memory trace evokes activation of the hippocampal index and activation of this hippocampal index results in activation of the corresponding entire memory trace in the neocortex

Temporally-graded amnesia refers to the fact that...

damage in the medial temporal lobes, especially in the hippocampus, typically impairs recent memories more severely than older memories. Amnesic patients may recall memories from their childhood almost normally, while being totally amnesic for events that occurred days, weeks, months, or even years prior to the damage. This is known as “Ribot’s law”.

True or False? The basic mechanism of learning is often suggested to be synaptic plasticity, that is, changes in connections between neurons.

True. Synaptic strengths change by experience . A memory trace is generated when synpactic activity causes more AMPA receptors to be  created and transferred to the postsynaptic receptor area of a dendrite. A memory trace is consolidated through a process in which new protein are made in the cell nucleus and transferred to dendritic spines. Consolidation mostly takes place during rest and sleep

What are the different time scales for memory trace generation and consolidation?

1–20 minutes: Initial memory trace generation (e.g., creation of more AMPA receptors in postsynaptic receptor area ).

2–4 hours: Consolidation through new protein synthesis in the cell nucleus.

Months or more: System-level consolidation and re-organization.

What happens to a consolidated memory trace when it is reactivated?

Reactivation destabilizes the memory trace, making it "labile" or vulnerable again. It then requires a time-limited process of reconsolidation, which depends on protein synthesis, to be restabilized.

How have researchers attempted to "erase" fear memories in humans?

By reactivating the fear memory and administering propranolol, a β-adrenergic receptor antagonist that interferes with protein synthesis. This blocks the reconsolidation process, neutralizing the fear-potentiated startle response on Day 3 without affecting explicit knowledge of the memory.

So the approach involves reactivation and blocking the reconsolidation.