Impulsivity

What is it?

• Acting or Done without Forethought•Latin Root: impulsivus = Driven Onward• Actuated or swayed by emotional or involuntary impulses• Proceeding from natural feeling or impulse without external stimulus• Doing things or tending to do things suddenly

Definition of Impulsive

What is Impulsivity?

Impulsivity has been variously defined as behavior without adequate thought, the tendency to act with less forethought than do most individuals of equal ability and knowledge, or a predisposition toward rapid, unplanned reactions to internal or external stimuli without regard to the negative consequences of these reactions.

Impulsivity is implicated in a number of psychiatric disorders including Mania, Personality Disorders, and Substance Use Disorders;

yet, there is significant disagreement among researchers and clinicians regarding the

exact definition of impulsivity and how it should be measured.

Definition of Impulsivity

http://www.impulsivity.org/

Actions that are • Poorly Conceived• Prematurely Expressed• Unduly Risky• Inappropriate to the Situation• Result in Undesirable Outcomes

• Dysfunctional: maladaptive•Act with less forethought, which produces difficulty

• Functional: Adaptive?• Act with little forethought when it is optimal

Impulsivity vs Risky Behavior

Are they the same?

Impulsivity vs Risky Behavior

Are they the same?

Impulsivity vs Risky Behavior

Risky?

Does Training matter for Impulsivity?

Impulsive?

• Not all impulsive behavior is disadvantageous• Impulsive individuals say they act with less forethought•But they often respond more slowly in experimental Tasks than non-impulsive individuals• Are decision time, persistence, boredom, and sensation seeking important aspects?

• Phenotypic Impulsivity• Negative consequences• Risky Behavior• Repetitive* • Not able to discern want from need• Underdeveloped PFC• less feedback from PFC to limbic• impatience• make choices even recognizing the negative consequences for that choice

Why don’t drugs work consistently?

• Drugs were delivered systemically –• Complex Behavioral Outputs• Such as Impulsivity• Require Complex Circuitry• Suggests multiple Transmitter modulation

• Is the Definition of Impulsivity Good Enough to determine multifactorial causation?

Do drug experiments strongly support the hypothesis that Impulsivity is multifactorial?

Transitional Bridge 5-choice serial reaction time task

Two New Models of Impulsivity

5CSRTT

5CSRTT

5CSRTT

Strong negative correlation r2=0.42 of premature responding with accuracy for Long ITI (5-10s)

Variable ITI (2-15s) – low correlation of premature responding and accuracy

Explains 42%

Explains 5%

5s

10s

Transitional Bridge

Transitional Bridge• COGNITIVE IMPULSIVITY• 2 bridges/remove panel 4• on platform A or C• trained → B or D• tone + food reward• √ bridge preference

•TESTING• A → B• immediate reward• C → D• 2X reward•5 s delay (3 days)

•7s delay (days 4-6)

• 10 s delay (7-9)

• Impulsivity =• choosing A → B• ↓ crossing latency

T-Bridge: Motor Impulsivity

T- Bridge: Cognitive Impulsivity

Toward Phenotypic ImpulsivityModels must include/consider • Behaviors meaningful to the animal used• Poor Conception is impossible to measure in animals and humans• Undue Risk•Situation Inappropriateness•Undesirable Outcomes• All affected by • Emotional state & Stress responsivity• Habitual, Learned and Not yet Learned behavior

The Next Step:

all individually variable}