Adolescent Δ9-Tetrahydrocannabinol Exposure Selectively Impairs Working Memory but Not Several Other mPFC-Mediated

Han-Ting Chen1,2, Ken Mackie1,2

  • 1Department of Psychology and Brain Sciences, Indiana University, Bloomington, IN, United States.

Frontiers in Psychiatry
|December 2, 2020
PubMed

Insights

Adolescent tetrahydrocannabinol (THC) exposure in mice impaired working memory establishment and recall. This cannabis exposure did not significantly alter anxiety, social behaviors, or decision-making in developing mice.

Area of Science:

  • Neuroscience
  • Developmental Psychology
  • Pharmacology

Background:

  • Increasing cannabis use among adolescents (14-16 years old) necessitates understanding its impact on the developing central nervous system.
  • The adolescent brain undergoes significant development, making it potentially vulnerable to the effects of psychoactive substances like tetrahydrocannabinol (THC).

Purpose of the Study:

  • To investigate the long-term effects of adolescent tetrahydrocannabinol (THC) exposure on cognitive functions in a mouse model.
  • To determine if adolescent THC exposure impacts specific behavioral domains, including working memory, social preference, anxiety, and decision-making.

Main Methods:

  • Adolescent male and female C57BL6/J mice (28 days old) were treated with 3 mg/kg tetrahydrocannabinol (THC) or vehicle for 3 weeks.
  • Cognitive behaviors, including working memory, social preference, anxiety, and decision-making, were assessed starting one week after the final THC treatment.
  • Working memory was evaluated using tasks assessing acquisition and recall under increasing cognitive load.

Main Results:

  • Adolescent THC-treated mice demonstrated slower acquisition of working memory tasks compared to controls.
  • Both male and female THC-exposed mice exhibited deficits in working memory recall under increasing cognitive load.
  • No significant effects of adolescent THC treatment were observed on social preference, anxiety-like behaviors, or decision-making in the elevated T maze task.

Conclusions:

  • Adolescent exposure to tetrahydrocannabinol (THC) significantly impacts the establishment and persistence of working memory in mice.
  • The findings suggest that adolescent THC exposure affects specific cognitive domains, particularly working memory, while having minimal influence on anxiety, social behaviors, or decision-making under the study's conditions.
  • This research underscores the specific vulnerability of the developing brain's working memory systems to cannabis exposure.

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