# Presentation: 143760

## Adolescent brain and behavior: Age-related sensitivities to natural rewards and drugs

- Linda Patia Spear
- Binghamton University
- Supported in part by grants R01 DA19071,      R37 AA12525 and R01 AA12150

## Adolescence

- transition between childhood/immaturity and adulthood/maturity
- prototypic age ranges:
- 	humans: 12-18 yrs. (early as 8-10; late as 25)
- 	rats: 28-42 days (early as 23-25; late as 55+)
- highly conserved physiological transitions:
- puberty
- other hormonal changes; growth spurt
- neural transformations
- common age-typical behavioral characteristics
- increases in peer-directed social behavior
- risk taking/novelty seeking/sensation seeking, impulsivity, etc.
- [species-specific characteristics as well]

## Slide 3

## Functional consequences of adolescent brain sculpting

- Relationship to hormonal reawakening of puberty?
- Reduction in brain energy utilization, and support of continued cognitive/emotional development
- Modulate highly conserved adolescent behaviors directed towards natural rewards

## Characteristic adolescent behaviors

***Increases in social interactions/peer affiliations***
**Develop social skills/support**
**Guide choice behavior**
**(may be associated with an increase in parent/ adolescent conflict)**

## CONDITIONED PLACE PREFERENCE

## Adolescent

- Subject Housing

- Coefficient (%)

- Adult

- Social CPP

## For adolescents, social history of stimulus 

- For adolescents, social history of stimulus
- animal matters

## For adolescents, social history of stimulus 

- For adolescents, social history of stimulus
- animal matters

## Social Avoidance during conditioning

## Social Avoidance during conditioning

## Adolescent animals are unusually sensitive to social stimuli
	-Adolescents (but not adults) show social CPP even when socially replete
	-Socially deprived adolescents exhibit marked increases in social behavior and are socially “ostracized” by non-deprived peers

- Adolescent animals are unusually sensitive to social stimuli
- 	-Adolescents (but not adults) show social CPP even when socially replete
- 	-Socially deprived adolescents exhibit marked increases in social behavior and are socially “ostracized” by non-deprived peers

## Characteristic adolescent behaviors

***Increases in social interactions/peer affiliations***
**Develop social skills/support**
**Guide choice behavior**
**(may be associated with an increase in parent/ adolescent conflict)**

***Increases in risk-taking, novelty-seeking, sensation-seeking, impulsivity***
**Impetus for exploring new territories, aiding in emigration**
**Enhance probability of reproductive success (Wilson & Daly)**
**Foster peer acceptance (Shedler **
**    ****& Block)**

## Novelty CPP –males

## Novelty CPP –males

- Time with object during condit.

- Novelty CPP

## Novelty CPP – females

- Time with object during condit.

## Novelty CPP – females

- Time with object during condit.

- Novelty CPP

## Novelty CPP

- Novelty exploration increased during adolescence
- Novelty CPP more robust in adolescent than adult males
- No age difference in novelty CPP in females
- Novelty exploration ≠ novelty reward

## Impulsivity in adolescence

## % Pellets received from LDH

- <date/time>

**Arc sine (% Pellets from LDH)**

- Experimental Day

- 1

- 2

- 3

- 4

- 5

- 6

- 7

- 8

- 9

- 10

- 11

- 12

- 0.4

- 0.6

- 0.8

- 1.0

- 1.2

- 1.4

- ADOL

- ADULT

## Interaction between impulsivity and ethanol intake

- <date/time>

- Impulsivity defined as SDH pokes during delay on Day 7

- Ethanol intake (g/kg)

- Ethanol intake (g/kg)

- Age

- Age

- ADOL

- ADULT

- 0

- 2

- 4

- 6

- 8

- 10

- ADOL

- ADULT

- 0

- 2

- 4

- 6

- 8

- 10

- LOW IMPUL

- HI IMPUL

- LOW IMPUL

- HI IMPUL

- Impulsivity defined as % rewarded pokes on Day 8

- (a)

- (b)

## Functional consequences of adolescent brain sculpting

- Relationship to hormonal reawakening of puberty?
- Support continued cognitive/emotional development
**Modulate highly conserved adolescent behaviors directed towards natural rewards **
**(social stimuli, risk taking/novelty seeking/impulsivity)**

- Influence sensitivity to and motivation for other
-    reinforcing/rewarding stimuli, including drugs

## Nicotine-induced CPP

**Nicotine-induced CPP**
- (0.6 mg/kg; biased design; 1 trial/day, saline control; group housed)

## Exposures

- 4

- 3

- 2

- 1

- Saline

- Nicotine

- Adolescents

- Number of Bouts

- 4

- 3

- 2

- 1

- Adults

- Locomotor Activity during Conditioning

## Summary

- Adolescence as a highly conserved developmental stage with certain common neurobehavioral features
- Sculpting of adolescent brain in mesocorticolimbic regions may influence reward-related behaviors
- Indeed, adolescents generally:
- spend more time engaged with social stimuli and novelty and are more impulsive than adults
- find:
- Social stimuli
- Novelty
- Nicotine            more rewarding/rewarding under more 			circumstances than adults
- Questions for the future:
- Neural substrates underlying specific adolescent-typical behaviors
- Adolescent-associated alterations in incentive motivation or hedonic value?

## Collaborators

- FACULTY collaborators:
- Terry Deak
- Juan Molina
- Lena Varlinskaya
- Brent Vogt
- Norman Spear
- Undergrad. honors students:
- Bonnie Vastola
- Kristin Osiecki
- Tom Washburn
- Mike Hernandez
- Michelle Baretto
- Scott Falkowitz

- Former and current graduate trainees:
- Marisa Silveri
- James Campbell
- Nina Katovic
- Drew Douglas
- Raj Pottayil
- Steve Brunell
- Tammi Doremus
- Rob Ristuccia
- Courtney Vetter
- Amanda Willey
- Carrie Wilmouth

- 	For futher info: lspear@binghamton.edu

## Slide 27