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Effect of Neonatal Handling on Learned Helplessness Model of Depression

Effect of Neonatal Handling on Learned Helplessness Model of Depression. Costella, Tejedor-Real, Mico, & Rahola Presented by Jamie Renspe June 21, 2007. Prior Research. Handled rats exhibited attenuated (i.e. less) fearfulness in new environments More exploratory behaviors

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Effect of Neonatal Handling on Learned Helplessness Model of Depression

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  1. Effect of Neonatal Handling on Learned Helplessness Model of Depression Costella, Tejedor-Real, Mico, & Rahola Presented by Jamie Renspe June 21, 2007

  2. Prior Research • Handled rats exhibited attenuated (i.e. less) fearfulness in new environments • More exploratory behaviors • Low emotional reactivity • Shorter escape latencies in a shuttle-box • Increases the reactivity to foot shocks • Reduces cognitive, learning, and memory impairments in older rats

  3. Model of DepressionLearned Helplessness • A laboratory model of depression in which exposure to a series of unforeseen adverse situations gives rise to a sense of helplessness or an inability to cope with or devise ways to escape such situations, even when escape is possible. http://www.answers.com/topic/learned-helplessness

  4. Model of DepressionLearned Helplessness • Prior Research • Lack of control • Lack of prediction

  5. Question • Will rat handling during early postnatal periods make rats less susceptible to helplessness in adulthood?

  6. Methods • Conditions • Control group • These rats were left undisturbed in their cages • 12 rats • Handled rats • Handled rats were removed from their cages and placed in a plastic container with a paper towel for 15 minutes every day • 8 rats

  7. Methods continued… • Open field tests • Circular open fields • Measured emotivity counting the number of boluses excreted • Induction of Learned Helplessness • Electric foot shocks (US) paired with light (CS)

  8. Methods continued… • Escape and Avoidance Performance • Automated two-way shuttle box • 2 chambers divided by a plastic partition or gate • Led into other compartment • Escape response • Would they attempt to escape? • Avoidance response • Escape failure • Failure for the rat to escape within 30-60 seconds • Escape latency • The time from the start of shock to the escape response

  9. Results • Handled rats excreted less boluses compared to non-handled rats during the second session of the open field test • Handled rats had less of an escape deficit • Handling reduced the mean escape latency after induction of helplessness during the shuttle box sessions • Handled rats made more avoidance responses after inescapable shock session

  10. Results continued…

  11. Results continued… • Handling reduces the level of emotivity • Handling reduces the susceptibility of learned helplessness • Endogenous opioids • Opioid-peptides that are produced naturally in the body • An opioid is a chemical substance that has a morphine-like action in the body

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