PSYC 3684 1st Edition Lecture 8Outline of Last Lecture I. Conception and ChildhoodOutline of Current Lecture II. AdolescenceIII. Implications of Adolescence brain developmentIV. Risky behaviorV. Adult hood and developmentCurrent LectureAdolescence- More effective information processingo Corpus callosum thickenso Lateralization = specialization of functioning Increased risky behaviorso Can brain development explain this?Adolescent Risky Behavior- Cross-sectional research suggested gradual maturation of the braino Linear decreased in gray matter and increase in white matter- Gredd (2004)o Longitudional study suggests something different, though- Methodo N=161, age 5-21 with MRI scans, 2 years apartResults- Gray matter increased and decreased at different rates for different brain areas, invertedU graph- Suggests a second wave of synaptogenesis and pruning- Prefrontal cortex, peaks at age 11 for girls and 12 for boys- AND did not reach maturity until age 20-25These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.Implications of Adolescent Brain Development- Second wave of synaptogenesis and synaptic pruning- Sensitive periodso Binge drinking in adolescent is associated with: Reduced synaptogenesis (Tafee et al 2010, Bava&Tapert 2010) Increased synaptic pruning to damaging levels (Squeglia, et all 2011)Neurobiological Model of Adolescent Risky Behavior- Imbalance model (Galvan 2012)o Limbic and striatal systems develop before the prefrontal cortexo (The thought of getting into a car and drunk driving to another fun and exciting party can be very exciting and enticing for adolescents)o Says that teenagers don’t really know how to say no to things that could be very dangerouso Governed by feelings and reward-seeking without control over ito Dopamine system is still developing Lower base levels of dopamine and GREATER releases, so positive feedback loop if there is more dopamine than children and adults getGalvan continued… 3 rd factor:- Context and environment- Revised imbalance modelContext: Risk vs. Resilience ApproachRisk factors:- Risky peers- Descriptive norms and perceptions of other people’s behaviors- Parental supply- MediaProtective Factors:- Older siblings- Religious beliefs- Parental modeling- Refusal assertiveness techniquesAdvantages of Imbalance- adolescents are more open to new experiences- enabling developing independenceAdulthood:- smaller brains- slower working brains- reduced lateralizationo function? Compensatory vs. declineNeurogenesis in adulthood- Mice  (Van Praag 2009)- Neurogenesis in dentate gyrus of hippocampus and olfactory bulb throughout adulthood- Normal age-related decline in neurogenesis may be related to deficits in cognition and memoryFactors influencing neurogenesis in adult mice:- Wheel running increased neuron activity- Cognitive challenges (like mazes or climbing sculptures) also increased neuron activity and enhanced neuron survival- Stress reduces neuron growth and activity!Neurogensis in Human Adults- Pereira et al 2007- Purpose  can neurogenesis in human adults be environmentally stimulated?Method:- N= 11 adults (age= 33)- 12- week exercise program (40 minutes aerobic exercise every day)- MRI’s at several points throughout 12 weeks- Memory task before and afterResults:- Increased cerebral blood volume in dentate gyrus- Improved on memory test AFTER exercise program (pretty neat!!)Conclusion:- Exercise induced neurogenesis in adults- Exercise may help reduce normal age-related cognitive declines and may increase the development of new