Stimulus selection in passive avoidance learning and retention: weanling, periadolescent, and young adult rats

Neuroscience & Biobehavioral Reviews

2016

Adolescence is an evolutionarily conserved developmental period, with neural circuits and behaviors contributing to the detection, procurement, and receipt of rewards bearing similarity across species. Studies with laboratory animals suggest that adolescence is typified by a “reward-centric” phenotype—an increased sensitivity to rewards relative to adults. In contrast, adolescent rodents are reportedly less sensitive to the aversive properties of many drugs and naturally aversive stimuli. Alterations within the mesocorticolimbic dopamine and endocannabinoid systems likely contribute to an adolescent reward-sensitive, yet aversion-resistant, phenotype. Although early hypotheses postulated that developmental changes in dopaminergic circuitry would result in a “reward deficiency” syndrome, evidence now suggests the opposite: that adolescents are uniquely poised to seek out hedonic stimuli, experience greater “pleasure” from rewards, and consume rewarding stimuli in excess. Future studies that more clearly define the role of specific brain regions and neurotransmitter systems in the expression of behaviors toward reward- and aversive-related cues and stimuli are necessary to more fully understand an adolescent-proclivity for and vulnerability to rewards and drugs of potential abuse.

Section: Adolescent Sensitivity To Rewardsmentioning

confidence: 99%

Reward-centricity and attenuated aversions: An adolescent phenotype emerging from studies in laboratory animals

Doremus-Fitzwater

Neuroscience & Biobehavioral Reviews

2016

“…For instance, in a classical conditioning paradigm using parameters that support aversions at both ages to a conditioned stimulus (CS) when paired with an aversive (footshock) unconditioned stimulus (US) in a particular context, adolescents have been varyingly reported to exhibit either stronger (Brasser & N. Spear, 2005; Esmoris et al, 2008; see also Barrett et al, 1984) or weaker (Pattwell et al, 2011) aversive (fear) conditioning to the training context than adults –differences perhaps due in part to dissimilarities across studies in salience of the contexts used. Intriguing age differences in cue reinstatement have also been reported.…”

Section: Adolescent Sensitivity To Aversive Stimuli and Punishmentsmentioning

confidence: 99%

Rewards, aversions and affect in adolescence: Emerging convergences across laboratory animal and human data

Developmental Cognitive Neuroscience

2011

Self Cite

252

214

The adolescent transition is associated with increases in reward- and sensation-seeking, peer-directed social interactions, and risk-taking, with exploratory use of alcohol and other drugs often beginning at this time. These age-related behaviors may have biological roots embedded in the evolutionary past, with similar adolescent-typical characteristics evident across a variety of mammalian species. Drawing across human behavioral and fMRI data and studies conducting in laboratory animals, this review examines processing of rewards, aversions, and affect in adolescence. Evidence for both hyper- and hypo-reactivity during adolescence in the processing of rewards is reviewed, along with possible contributors to these differences. Indications of sometimes heightened reward reactivity during adolescence are contrasted with frequent attenuations in adolescent sensitivity to aversive stimuli. At the same time, adolescents appear particularly prone to becoming emotionally aroused, especially in social contexts. Emerging evidence hints that exaggerated adolescent reactivity in reward and affective systems may be promoted in part by unusual strong cross-reactivity between these systems during adolescence. Such age-related propensities may promote adolescent risk taking, especially in social and exciting contexts, and contribute to adolescent-typical propensities to attach greater benefit and less cost to risky behaviors such as alcohol and drug use than individuals at other ages.

“…For instance, in a passive avoidance task, an older study found that adolescent rats were less disrupted by a change in a redundant discriminative cue, while more disrupted by a contextual change than younger or older rats (Barrett et al, 1984). In recent work, less cue-induced reinstatement of drug intake was seen in rats trained to self-administer cocaine or morphine in adolescence compared to animals that initiated drug use as adults (Doherty et al, 2009, Li & Frantz, 2009), data also commensurate with the suggestion that adolescents may perhaps attribute motivational salience to stimuli differently than do adults.…”

Section: Adolescent Motivation For Natural Rewards and Drugs Of Amentioning

confidence: 99%

Motivational systems in adolescence: Possible implications for age differences in substance abuse and other risk-taking behaviors

Doremus-Fitzwater

Varlinskaya

2010

Brain and Cognition

353

257

Adolescence is an evolutionarily conserved developmental phase characterized by hormonal, physiological, neural and behavioral alterations evident widely across mammalian species. For instance, adolescent rats, like their human counterparts, exhibit elevations in peer-directed social interactions, risk-taking/novelty seeking and drug and alcohol use relative to adults, along with notable changes in motivational and reward-related brain regions. After reviewing these topics, the present paper discusses conditioned preference and aversion data showing adolescents to be more sensitive than adults to positive rewarding properties of various drugs and natural stimuli, while less sensitive to the aversive properties of these stimuli. Additional experiments designed to parse specific components of reward-related processing using natural rewards have yielded more mixed findings, with reports of accentuated positive hedonic sensitivity during adolescence contrasting with studies showing less positive hedonic affect and reduced incentive salience at this age. Implications of these findings for adolescent substance abuse will be discussed.