The role of sleep in fear learning and memory

Background: Learning and memory is basic aspects in neurogenetics as most of the neurological disorders start with dementia or memory loss. Several genes associated with memory formation have been discovered. MicroRNA genes miR-1000 and miR-375 were reported to be associated with neural integration and glucose homeostasis in some insects and vertebrates. However, neuronal function of these genes is yet to be established in D. melanogaster. Objective: Possible role of miR-1000 and miR-375 in learning and memory formation in this fly has been explored in the present study. Methods: Both appetitive and aversive olfactory conditional learning were tested in the miR-1000 and miR-375 knockout (KO) strains and compared with wild one. Five days old third instar larvae were trained by allowing them to be associated with an odor with reward (fructose) or punishment (salt). Then, the larvae were tested to calculate their preferences to the odor trained with. Learning index (LI) values and larval locomotion speed were calculated for all strains. Results: No significant difference was observed for larval locomotion speed in mutant strains. Knockout strain of miR-1000 showed significant deficiency in both appetitive and aversive memory formation whereas miR-375 KO strain showed a significantly lower response only in appetitive one. Conclusion: The results of the present study indicate important role played by these two genes in forming short-term memory in D. melanogaster.

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Marijuana and β-estradiol interactions on spatial learning and memory in young female rats: Lack of role of the G protein-coupled estrogen receptor (GPR30)

Life Sciences ◽

10.1016/j.lfs.2021.119723 ◽

2021 ◽

pp. 119723

Author(s):

Mohadeseh Chahkandi ◽

Gholamreza Komeili ◽

Gholamreza Sepehri ◽

Mohammad Khaksari ◽

Sedigheh Amiresmaili

Keyword(s):

Estrogen Receptor ◽

Learning And Memory ◽

G Protein ◽

Spatial Learning ◽

Young Female ◽

Female Rats ◽

Spatial Learning And Memory ◽

G Protein Coupled

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Observational Fear Learning in Rats: Role of Trait Anxiety and Ultrasonic Vocalization

Brain Sciences ◽

10.3390/brainsci11040423 ◽

2021 ◽

Vol 11 (4) ◽

pp. 423

Author(s):

Markus Fendt ◽

Claudia Paulina Gonzalez-Guerrero ◽

Evelyn Kahl

Keyword(s):

Trait Anxiety ◽

Conditioned Fear ◽

Ultrasonic Vocalization ◽

Fear Learning ◽

Anxiety State ◽

Learning Procedure ◽

The Social ◽

Medium Level ◽

Male Wistar Rats

Rats can acquire fear by observing conspecifics that express fear in the presence of conditioned fear stimuli. This process is called observational fear learning and is based on the social transmission of the demonstrator rat’s emotion and the induction of an empathy-like or anxiety state in the observer. The aim of the present study was to investigate the role of trait anxiety and ultrasonic vocalization in observational fear learning. Two experiments with male Wistar rats were performed. In the first experiment, trait anxiety was assessed in a light–dark box test before the rats were submitted to the observational fear learning procedure. In the second experiment, ultrasonic vocalization was recorded throughout the whole observational fear learning procedure, and 22 kHz and 50 kHz calls were analyzed. The results of our study show that trait anxiety differently affects direct fear learning and observational fear learning. Direct fear learning was more pronounced with higher trait anxiety, while observational fear learning was the best with a medium-level of trait anxiety. There were no indications in the present study that ultrasonic vocalization, especially emission of 22 kHz calls, but also 50 kHz calls, are critical for observational fear learning.

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