Memory and Behavior in Roaches and Mice

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Questions and Answers

What behavior did roaches display after finding the apple slice at the peppermint?

They stopped visiting the peppermint altogether.

They showed a reduced number of visits to the vanilla odor. (correct)

They continued to visit the vanilla odor more frequently.

They increased their visits to both odors equally.

What can be inferred about the memory capacity of the roaches during training?

They were unable to remember the odors effectively.

They displayed both short-term and long-term memory. (correct)

They only retained information for longer than a week.

They only demonstrated short-term memory.

Which factor did NOT contribute to the performance change in roaches after training?

The presence of apple slices at the peppermint.

The interval between training trials. (correct)

The time elapsed since the training.

Position of the peppermint relative to vanilla.

What is the impact of misaligned feeding on memory recall in mice?

It disrupts time-dependent memories. Signup and view all the answers

When does peak performance for contextual fear conditioning (FC) typically occur?

During sleep (day). Signup and view all the answers

What was the initial behavioral pattern of roaches regarding the vanilla odor?

They visited the vanilla odor six or more times before peppermint. Signup and view all the answers

In the context of memory tasks, how does the novel object recognition (NOR) test relate to time of day?

It yields peak performance when mice are awake. Signup and view all the answers

What does the consistency in performance at different times after training suggest about roaches?

Their memory and learning were stable over time. Signup and view all the answers

What is one factor that can disrupt memory tasks such as NOR and FC?

Misaligned feeding. Signup and view all the answers

Which core clock gene's knockout is associated with memory tasks?

Bmal1. Signup and view all the answers

What effect does a rapid change in the light-dark cycle have on the recall ability of mice?

It disrupts their ability to recall contextual fear conditioning. Signup and view all the answers

Which scenario results in mice forgetting faster according to the study?

Being trained before an advance phase shift and tested after. Signup and view all the answers

What was observed regarding the acquisition of fear conditioning under phase shifted conditions?

Acquisition was not impacted. Signup and view all the answers

When is the ability to recall contextual fear conditioning adversely affected according to the findings?

When trained while experiencing jet lag. Signup and view all the answers

What specific change in the light-dark cycle was examined in the study's Model 1?

A rapid advance phase shift. Signup and view all the answers

Which of the following best describes the graph pertaining to freezing behavior in mice?

Phase-shifted mice showed higher freezing rates compared to controls initially. Signup and view all the answers

What is suggested about the timeline of forgetting in mice trained under altered light conditions?

Forgetting occurs rapidly within certain days after training. Signup and view all the answers

What does the term 'contextual fear conditioning' refer to in the study?

Mice associating a specific environment with an aversive experience. Signup and view all the answers

What is the primary distinction between operant conditioning and classical conditioning?

Operant conditioning involves voluntary behaviors, while classical conditioning involves involuntary responses. Signup and view all the answers

In the context of the Novel Object Recognition (NOR) test, what does a high Discrimination Index indicate?

The animal focuses primarily on the novel object and ignores the familiar one. Signup and view all the answers

Which of the following best illustrates an example of operant conditioning?

A dog learns to sit in response to a command when given a treat. Signup and view all the answers

What is the role of discriminative stimuli in operant conditioning?

They signal when a behavior will be rewarded or punished. Signup and view all the answers

In a Fear Conditioning test, what outcome results from pairing an aversive stimulus with a neutral stimulus?

The neutral stimulus alone eventually triggers a fear response. Signup and view all the answers

What type of behavior does classical conditioning primarily involve?

Involuntary responses to paired stimuli. Signup and view all the answers

Which statement correctly describes a key feature of operant conditioning?

It involves choices between different behaviors. Signup and view all the answers

During a Novel Object Recognition test, which behavior pattern suggests successful memory retention by the animal?

Spending more time with the novel object than the familiar one. Signup and view all the answers

What is the effect of surgical ablation of the biological clock via optic lobe removal (OLX) on memory formation?

It rescues the animal’s ability to form memories at CT 2. Signup and view all the answers

What does the circadian system inhibit according to the study?

Memory formation during CT 2 Signup and view all the answers

What neurotransmitter is indicated as key to memory inhibition at CT 2?

GABA Signup and view all the answers

What genetic modification was made to study the effects of Bmal1 in forebrain excitatory cells?

Bmal1 targeted deletion in forebrain excitatory neurons Signup and view all the answers

In which region of the brain was Bmal1 expression disrupted in the Bmal1 (fl/fl) mice?

CTX and GCL Signup and view all the answers

What outcome was observed when the SCN was lesioned in the study on hamsters?

Memories could be stored during the usual non-learning period. Signup and view all the answers

What was the primary observable behavior in the locomotor activity of the Bmal1 fKO mouse?

Normal locomotor activity Signup and view all the answers

At which time does the optic lobe removal (OLX) most notably rescue memory formation?

CT 2 Signup and view all the answers

Which method was used to assess learning based on time-of-day in the mice?

Novel object location (NOL) test Signup and view all the answers

In operant conditioning, what does OLX abolish according to the findings?

The circadian rhythm in recall Signup and view all the answers

What does the CaMKII-CRE driver specifically target in the forebrain?

Excitatory neurons Signup and view all the answers

Which of the following statements best describes the relationship between the circadian system and memory formation?

Inhibitory phases inhibit memory formation when conditions are met. Signup and view all the answers

What phenomenon was noted about Bmal1 expression in the CRE:Bmal1 (fl/fl) mice?

Some forebrain cells still expressed Bmal1 Signup and view all the answers

What was the sample size used in the classical conditioning study with Sham and OLX at CT 2?

7 for Sham and 13 for OLX Signup and view all the answers

Which expression pattern is associated with the gene Bmal1 in the study's context?

Circadian rhythm regulation primarily in excitatory cells Signup and view all the answers

What characterization best describes the Bmal1-”floxed” mouse line?

A conditional knockout model for specific neuronal targeting Signup and view all the answers

Study Notes

BSci 3230 Study Notes

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Circadian Regulation of Learning and Memory

The presentation discusses how circadian rhythms affect learning and memory, particularly comparing mice and cockroaches.
"Sometimes Cockroaches are Smarter Than They Appear to Be," highlights the presentation's focus.

Learning & Memory Terms

Operant Conditioning: Stimuli present during reward or punishment control behavior; voluntary. Examples include a child learning to open a box for candy or avoiding a hot stove.
Classical Conditioning: Involuntary behaviors based on associations with biologically significant events; not based on consequences. Examples include salivating at the sight of candy or trembling at a door slam that signals an angry parent.

Novel Object Recognition (NOR) & Fear Conditioning

NOR test: Measures how well an animal remembers a familiar object and ignores it. A high Discrimination Index means the animal spends more time with a new object.
Fear Conditioning test: Pairing an aversive stimulus (e.g., shock) with a neutral context (e.g., cage) or stimulus (e.g., tone) creates fear responses to the originally neutral stimulus.

Learning/Memory & Clocks

Circadian suppression of memory formation/recall can occur at "inappropriate" times.
Disruptions in circadian rhythms affect learning and memory processes.

Zeitgedächtnis ("Time Memory") in Bees

Bees in the experiment by Beling (1929) showed time-dependent memory.
The bees continued to visit a sugar source at the same time each day, even when the sugar was removed.

Diurnal Variation in Learning and Memory

Diurnal variation (daily rhythm) in learning and memory is common across species.
Humans, while showing circadian rhythms, often haven't had their learning and memory studied under consistent conditions in the laboratory.
Other species continue showing these rhythms even in constant conditions. The example studied suggests this regularity in rhythm is circadian.

Mouse Memory Tests

Contextual fear conditioning (FC): Studies daily/circadian rhythms of memory acquisition, recall, and extinction.
Novel object recognition (NOR): Tests recognition of objects and how misaligned feeding affects mice memories.
Novel object location (NOL): Studies novel object location in the lab environment, related to time of day, and the effects of core clock gene knockout (Bmal1).

Fear Conditioning Protocol

Mice conditioned to fear stimuli at specific times show circadian related learning based on the time of day the conditioning or testing happened.

Circadian Variations in Acquisition

Training mice in different circadian phases influences how quickly they learn fear conditioning responses.
Some tasks are faster in the day (or subjective day) for fear conditioning. Circadian variation in responses to fear conditioning was clear in the tests.

Rhythms in Recall of Training

Mice show clear circadian rhythms in recall responses. Memory recall best in a particular period after training.

Forgetting ("Extinction")

The rate of forgetting varies with training and testing times, more forgetting when trained in the inactive phase or when the cycle was shifted.
Memory forgetting is related to the time of day traumatic events happened for the studies. This is relevant to PTSD in humans.

Mouse Memory Tests (Repeated Section)

Contextual fear conditioning: Evaluates circadian rhythms in acquiring, recalling, and forgetting memories. Includes jet lag and misaligned feeding effects.
Novel object recognition (NOR): Studies recognition of objects.
Novel object location (NOL): Examines how time of day affects memory of object locations in the lab.
Core clock gene (Bmal1) knockout: Investigate how removing or altering core clock genes impacts learning and memory.

Model 1: Rapid Change in the LD Cycle

Rapid changes in the light-dark cycle disrupt the ability to remember contextual fear conditioning (recall) in mice.

Model 1: Phase Shifts Before Training

Mice were trained during testing, demonstrating the phase shift can inhibit recall.

Model 2: Misaligned Feeding Schedules

Misaligned feeding disrupts activity rhythms, resulting in various physiological effects.

Hippocampal Neurons

Hippocampal neurons are weak circadian oscillators.

Misaligned Feeding Alters Phase of Molecular Oscillations

Misaligned feeding affects the phase of molecular oscillations (the molecular, cellular, and systemic timing of the 24-hour cycles) in the SCN (Suprachiasmatic Nucleus), hippocampus, and liver. Misalignment disrupts the temporal synchrony of those tissues.

Misaligned Feeding Interferes with Memory

Misaligned feeding disrupts memory formation, especially in contextual fear conditioning and novel object recognition (NOR) tasks.

Model 3: Targeted Loss of Bmal1 in Forebrain

Removing the Bmal1 gene in the forebrain (part of the brain) shows a normal circadian activity rhythm for mice.
Researchers used specialized methods (CaMKII-CRE driver) to target loss of Bmal1 to specific cell types in the forebrain.
Removing or altering core clock genes impacts learning and memory.

Time-of-day Dependent Learning

Time of day affects learning and memory in mice, and appears to interact with circadian systems as a vital component for recall.

Cockroach Memory Tests

Classical Conditioning: Involuntary behaviors based on stimulus associations.
Operant Conditioning: Voluntary behaviors based on reward or punishment association.

Olfactory Discrimination Test

Cockroaches prefer vanilla to peppermint naturally.
In olfactory discrimination, odor preference and discrimination don't change with circadian phase.

Classical Olfactory Conditioning

Conditioning roaches to associate odors with rewards or punishments.
Roaches prefer vanilla and dislike peppermint.

Can Cockroaches Learn?

Cockroaches can learn to associate an odor (peppermint) with a reward (sugar) in the early subjective night.
The association with the reward may modify the odor preference in the training period. Early subjective night training has a stronger association with learning.

A Circadian Rhythm in Learning and Memory

Rats/Cockroaches trained and tested at the same phase of their circadian cycle show improved learning and memory.
When the time of learning and recall is different from the circadian cycle, memory performance varies.

Is the Deficit at CT 2 Due to a Deficit in Memory Formation or a Deficit in Memory Recall?

In a recall test, memory is not stored well and recall is poor when tested during the early subjective day; however, this deficit is an inability to store new memories, and not in recalling already established memories.

Operant Olfactory Conditioning

Pairing an unpleasant odor (peppermint) with an inaccessible reward (apple) to change the cockroach's behavior patterns.

Does the Circadian System's Effect Depend on the Type of Training?

Whether circadian rhythms affect learning and memory depends on the type of training used (e.g.; operant methods). In some cases, the circadian time of the training had little effect on performance in the test. Recall was still possible.

With Operant Conditioning, Recall Is Dependent On Circadian Phase

Operant training at different circadian phases affect whether roaches can recall, showing time of training is a critical factor.

Classical Conditioning: The Optic Lobe Clock Inhibits Memory Formation

Optically-induced ablation to the circadian timing system impacts the ability to establish new memories, especially with classical conditioning.
Circadian-timed memory formation, especially the creation of new memories, is diminished during the early subjective day.

Classical Conditioning: Inhibition at CT 2 by GABA

GABA (a neurotransmitter) can affect memory formation in a circadian dependent manner.
In classical conditioning tests using insects (roach), GABA neurotransmitters, which are involved in inhibition, are critical to inhibiting memory formation in a certain time window.

Conclusions

The circadian system heavily influences learning and memory.
The impact varies with the method of training and among species.
Inhibition in the circadian system, possibly by GABA, seems to be a widespread mechanism affecting learning and memory at particular times of the day.

Food for Thought

What evolutionary benefits does being less effective at learning/remembering at certain times of day provide?
How does the brain store and retrieve information related to memory phases?
When is the ideal time for human learning/memory studies?

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Description

This quiz explores the memory and behavioral responses of roaches and mice under various experimental conditions. Questions cover topics such as memory capacity, contextual fear conditioning, and the effects of feeding schedules on recall performance. Test your understanding of how these factors influence memory in different species!