develop psych sem 2 lec 3

Development of the Emotional Brain

Authors: B.J. Casey, Aaron S. Heller, Dylan G. Gee, Alexandra O. Cohen
Published in: Neurosci Lett. 2019 February 06; 693: 29-34. doi:10.1016/j.neulet.2017.11.055.

Abstract

  • Highlights the dynamic reorganization of neural circuitry during adolescence related to emotional development.

  • Offers a neurobiological account of hierarchical, circuit-based changes coinciding with emotional development.

  • Imaging studies indicate changes in limbic and cognitive control circuitry are pronounced during adolescence.

  • Proposes hierarchical changes in circuitry:

    • From subcortico-subcortical

    • To subcortico-cortical

    • Then to cortico-subcortical

    • Finally to cortico-cortical

  • Each level's changes are necessary for the successive emergence of emotional reactivity and regulation from adolescence to young adulthood.

Keywords

  • Adolescence; development; emotion; limbic; prefrontal cortex

Introduction

  • Literature Overview: Rapidly evolving studies on the emotional brain explore changes in emotional behavior, especially during adolescence.

  • Mental Disorders Peak: Incidence of mental disorders linked to emotion dysregulation peaks during adolescence.

  • Vulnerability: Adolescence is sensitive to influences from social and emotional environments.

Key Questions Addressed:

  1. How do changes in neural circuitry explain emotional reactivity and regulation during adolescence?

  2. When does emotional regulation reach adult levels, and how does this vary across emotional contexts?

Neurobiological Models of Adolescence

  • Proposed Models: Various models explain neurobiology underlying fluctuating emotions and reduced emotional control during adolescence.

    • Dual Systems Model: Emphasizes competing cognitive control and emotional systems, indicating breakdown in structure when emotional systems dominate less mature cognitive controls.

    • Supported by empirical findings that highlight reward versus control systems.

    • Effective for public understanding and informing youth protection policies.

    • Imbalance Model: Focuses on the nonlinear ways emotion reactivity and regulation develop.

    • Suggests interactions between multiple circuits from subcortical to cortical levels.

    • Aspects of developmental changes in behavior correlate with regional fine-tuning of limbic and cortical circuits.

    • Highlights developmental pathways as hierarchical rather than mismatched or competing systems.

  • Evidence: Supports the imbalance model through postmortem studies showing selective stabilization in excitatory synapses in prefrontal regions.

    • Neuroimaging Studies: Show patterns of regional brain changes with development and functional connectivity implicating the evolution of local circuits before distal cortical refinements.

  • Cascading Developmental Events: Mechanisms of neurodevelopmental cascades parallel psychological theories regarding behavior.

    • Thelen's Hierarchical View: Development phases build on previous ones, emphasizing interconnectedness among brain regions.

Developmental Changes in Neural Circuits and Emotional Regulation

Subcortico-Subcortical Connectivity

  • Major focus on amygdala and ventral striatum regarding emotional processes.

    • Ventral Striatum: Involved in learning and predicting positive outcomes, receives input from the basolateral amygdala.

    • Amygdala: Facilitates motivated action and learns emotional significance of environmental cues.

  • Connection studies have revealed impulsive behaviors linked to amygdala-ventral striatum connectivity during youth; impulsivity appears prominent in early adolescence irrespective of cue valence (positive or negative).

    • Research Example: Heller et al. (2016) conducted a fMRI study suggesting a relationship between connectivity and impulsivity in response to emotional cues.

Subcortico-Cortical Connectivity

  • As emotional circuitry develops, relationships between subcortical structures and prefrontal regions become evident, particularly when resolving conflicted emotions from rewards and punishments.

    • Tye et al. Studies: Indicate how amygdala-prefrontal inputs guide behaviors amid mixed emotional cues.

    • Highlight the need for subcortico-cortical development for proper emotion regulation.

Cortico-Subcortical Connectivity and Emotion Regulation

  • Development of top-down modulation from cortical projections leads to reduced reflexive emotional responses.

  • Ventromedial prefrontal cortex (vmPFC) connectivity shows slower maturation compared to subcortical connections.

    • It shifts from positive to negative as individuals grow from childhood to adulthood.

  • Research indicates that robust subcortical signaling facilitates the strengthening of cortical projections understood through resting-state and task-based functional connectivity studies.

Cortico-Cortical Connectivity

  • The discovery of roles played by lateral prefrontal cortex (PFC) in cognitive reappraisal emphasizes cognitive modulation of emotional circuitry.

  • Age-related improvements in cognitive control correlate with heightened coupling between vmPFC and lateral PFC enabling proper emotional attention and regulation.

Timing of Emotional Development to Adult Levels

  • Offers a complex view whereby cognition and emotion regulation transitions reach an adult-like level before complete societal integration (typically around age 18).

  • Studies by Cohen et al. indicated varying capacities for emotional control seen in different age groups during emotionally charged tasks.

    • Findings: Teens and young adults demonstrated less effective cognitive control during emotional states compared to older adults, with significant neurofunctional implications.

Conclusions

  • Shift in neurodevelopmental understanding from simple dichotomy theories to circuit-based approaches.

  • Suggests emotional development consists of cascading changes in neural connection structure from subcortical circuits to cortical networks.

  • Emphasizes that maturation in emotional and cognitive control is not only linear but layered, necessitating both temporal and relational developmental frameworks.

    • These insights underscore important implications for legal and social policy concerning youth mental health and development.

Acknowledgments

  • Supported by:

    • U01 DA041174 (BJC)

    • MacArthur Foundation Research Network on Law and Neuroscience (BJC)

    • DP50D021370 (DGG)

    • National Science Foundation Graduate and Postdoctoral Research Fellowship (AOC).

References

  • Lists key literature providing evidence for discussed theories and findings, including those from Casey, Lee, Shulman, and others regarding adolescent brain development and neurobiology.