Neurocognitive Development

Neurocognitive Development

1. Cognition

   • mental abilities: Attention, Memory, Decision-making, etc
   • changes considerably over lifespan, more than any other mental abilities
   • Reason for Human's unique higher cognition
     • evolved brain
       • Highest brain size to body size ratio
       • largest prefrontal cortex proportion
         • Why do we need a prefrontal cortex
           • cognitive flexibility: integrative function between sensory, motor, and higher cognitive regions
             • animal without this are limited to simple approach and avoid behaviors
           • Important regulatory role--> "top-down" processing: governance over other brain regions
             • guiding behavior base on goals and ways to achieve them
               • Cognitive control: goal-driven behavior in the face of distraction, those with prefrontal damage have a hard time

2. Typical Development

   • Structural Development
     • Brain develops from the back to the front
       • Prefrontal cortex(PFC) is the last brain region to develop and undergoes synaptic pruning the last
     • NIMH Longitudinal study of brain structure
       • gray matter follows inverted-U shaped trajectory
         • peaks in early to mid adolescence
       • white matter follows linear trajectory
         • white matter
           • increase speed of transmission
           • greater integration of disparate brain regions
           • modulates timing/ synchrony of neuron firing
   • Functional Development
     • Immature Cognitive Control
       • limited ability to control behavior in the face of distraction, emotion, challenge
         • Go/ No-Go Test
           • Adults more accurate on incongruent and no-go trails
             • Children showed a greater interference effect(much longer time for incongruent than neutral)
           • Interference Suppression
             • Adults show greater activation during interference suppression in the right PFC
               • greater PFC activation --> less susceptible to interference(distraction)
     • functional development of the prefrontal cortexs supports maturation of cognitive control
       • delay gratification
         • high delayers more PFC activation, better cognitive control-->inhibit no-go response
       • emotional interference
         • Kids and teens' cognitive control is more disrupted by -->perform worse in negative emotion trials
           • can be adaptive for staying away from harms
       • incentives
         • improve performance for teens but not adults
           • teens' brain more sensitive to rewards
             • more susceptible to external info--> beneficial
             • greater activation in the ventral striatum (reward- related region)

3. Atypical Development

   • delayed shifts
     • same general shape but shifted to the right
       • peak at later age(~11.5) compared to the healthy group(~10)
       • ADHD
         • examine cortical maturation(peak thichkenss)
           • not simply a deviation in cortical maturation but a delay in specific regions
           • "growing out" of ADHD may be the result of normalization of initial delays
           • Stable(lifelong) ADHD may be the result of a deviant trajectory
   • disrupted velocity
     • show the same developmental trajectory but the speed is altered
       • Pruning occurs sooner and faster
     • Schizophrenia
       • Loss rate of gray matter was faster in kids with schizophrenia
   • deviant trajectories
     • No resemblance of typical development

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