Adolescence: what do transmission, transition, and translation have to do with it?

Abstract

Negotiating the transition from dependence on parents to relative independence is not a unique demand for today's youth but has a long evolutionary history (transmission) and is shared across mammalian species (translation). However, behavioral changes observed during this period are often described as delinquent. This review examines changes in explorative and emotive behaviors during the transition into and out of adolescence and the underlying neurobiological bases in the context of adaptive and maladaptive functions.

Figure 1. Model of adolescent development

Prolongation of adolescence may result in increases in the duration and the degree (magnitude) of an imbalance between hormonally driven limbic processes relative to age-dependent (experience) driven cortical processes, In the cartoon above, cortical control is represented in blue, subcortical reactivity in pink, and red represents a further shift with earlier pubertal onset. Increasing the duration and degree of this imbalance may lead to greater difficulty as the individual moves from dependence on parents to relative independence.

Figure 2. Behavioral performance to appetitive relative to non appetitive social cues across development

Gray line represents missing a target go trial (misses); black line represents making a commission error (false alarm) by inappropriately responding to a nontarget when instructed to withhold a response. Behavioral performance is biased towards appetitive social cues (happy faces) relative to nonappetitive social cues (calm faces) during adolescence relative childhood or adulthood. Adapted from Somerville et al. (2010), Journal of Cognitive Neuroscience.

Figure 3. Development of ventral frontostriatal function

A) Ventral striatal region showing differential activity as a function of age. B) Plot of ventral striatal activity to appetitive cues as a function of age. C) Differential activity in the inferior frontal gyrus as a function of task (nogo > go). D) Plot of inferior frontal gyrus activity to nogo relative to go trials as a function of age. Recruitment decreases linearly with age. From Somerville et al. (2010), Journal of Cognitive Neuroscience.

Figure 4. Developmental and individual differences in amygdala responses to empty threat

A) Greater engagement of the amygdala to empty threat (fearful faces) in adolescents relative to children or adults. B) Localization of amygdala activation on a coronal image. C. Association of habituation of amygdala response with repeated exposure to empty threat and everyday ratings of anxiety. Adapted from Hare et al. (2008), Biological Psychiatry.