Towards the study of functional brain development in depression: an Interactive Specialization approach

Abstract

Depression is a significant and impairing mood disorder with onset possible as early as age 3 and into adulthood. Given this varying pattern of age of onset, identifying the relationship between brain development and depression across the lifespan has proven elusive. This review identifies some of the factors that may have limited the advancement of our knowledge in this area and discusses how synthesizing established models of depression and normative brain development may help to overcome them. More specifically, it is suggested that current neurobiological models of depression fail to account for the developmental variance associated with early neural network development and the potential influence of experience on this process. The utility of applying an established framework of normative brain development to this topic is described and its potential utility for conceptualizing the influence of depression on brain function across the life span is addressed. Future directions including longitudinal neuroimaging studies of early onset depression and groups at risk for this disorder are proposed.

Figure 1. Competing neurobiological models of brain development and later skill emergence

The figure illustrates (a) a maturational account where skill emergence is associated with cortical regions previously silent prior to maturation, (b) an interactive specialization account where skill emergence is associated with developing interactions between cortical/subcortical regions, and (c) a skill learning account where skill emergence is associated with a transition from greater frontal to posterior activity following the eventual establishment of a given skill. Reprinted by permission from Macmillan Publishers LTD: Nature Reviews Neuroscience, Johnson, M.H. (2001). Functional brain development in humans. 2(7), Pg. 479.

Figure 2. Representative neurobiological model of emotion regulation and its disruption in mood disorders

Neurobiological model of emotion regulation depicting dorsal and ventral regions commonly implicated in mood disorders, including depression. Arrows in the figure depict a disrupted relationship between control (depicted as ovals) and emotion generating (depicted as stars) regions. Refer to the figure for an explanation of the colors used. Reprinted by permission from Macmillan Publishers LTD: Molecular Psychiatry, Phillips, M.L., Ladouceur, C.D., & Drevets, W.C., (2008). A neural model of voluntary and automatic emotion regulation: implications for understanding the pathophysiology and neurodevelopment of bipolar disorder. 13(9), Pg. 849.

Figure 3. Representative neurobiological model of core- and extended face processing networks

A simplified neurobiological model of face processing including core- and extended face processing networks. Regions included in the core face processing network include inferior occipital gyri, fusiform gyrus, and superior temporal sulcus. The extended network is composed of regions including the amygdala, ventromedial/orbitofrontal cortices, anterior insula, and anterior cingulate gyrus (among others). Regions shaded in yellow are intended to represent those involved in processing identity and associated semantic information, those in red represent regions involved in emotion analysis, and those in blue represent regions involved in spatial attention. As can be seen in the figure, some regions are suggested to have multiple roles. Reprinted from Neuropsychologia, 45(1), Palermo, R., & Rhodes, G., Are you always on my mind? A review of how face perception and attention interact., Pg. 76, 2007, with permission from Elsevier.