Unbiased Stereological Estimates of Dopaminergic and GABAergic Neurons in the A10, A9, and A8 Subregions in the Young Male Macaque.

The ventral midbrain is the primary source of dopamine- (DA) expressing neurons in most species. GABA-ergic and glutamatergic cell populations are intermixed among DA-expressing cells and purported to regulate both local and long-range dopamine neuron activity. Most work has been conducted in rodent models, however due to evolutionary expansion of the ventral midbrain in primates, the increased size and complexity of DA subpopulations warrants further investigation. Here, we quantified the number of DA neurons, and their GABA-ergic complement in classic DA cell groups A10 (midline ventral tegmental area nuclei [VTA] and parabrachial pigmented nucleus [PBP]), A9 (substantia nigra, pars compacta [SNc]) and A8 (retrorubral field [RRF]) in the macaque. Because the PBP is a disproportionately expanded feature of the A10 group, and has unique connectional features in monkeys, we analyzed A10 data by dividing it into 'classic' midline nuclei and the PBP. Unbiased stereology revealed total putative DA neuron counts to be 210,238 ±â€¯17,127 (A10 = 110,319 ±â€¯9649, A9 = 87,399 ±â€¯7751 and A8 = 12,520 ±â€¯827). Putative GABAergic neurons were fewer overall, and evenly dispersed across the DA subpopulations (GAD67 = 71,215 ±â€¯5663; A10 = 16,836 ±â€¯2743; A9 = 24,855 ±â€¯3144 and A8 = 12,633 ±â€¯3557). Calculating the GAD67/TH ratio for each subregion revealed differential balances of these two cell types across the DA subregions. The A8 subregion had the highest complement of GAD67-positive neurons compared to TH-positive neurons (1:1), suggesting a potentially high capacity for GABAergic inhibition of DA output in this region.

Measuring Adolescents' Self-injurious Thoughts and Behaviors: Comparing Ecological Momentary Assessment to a Traditional Interview.

The purpose of this study was to compare adolescents' reports of self-injurious thoughts and behaviors (SITBs) between ecological momentary assessment (EMA) and a traditional, retrospective interview. Adolescents were recruited following recent discharge from acute psychiatric care for a suicidal crisis (as part of a larger study). Participants completed: (1) EMA surveys assessing SITBs multiple times daily over a 28-day follow-up period, and (2) a follow-up phone interview to evaluate SITBs retrospectively at the end of the same 28-day follow-up period. Forty-one adolescents completed the final follow-up interview (Mage = 14.9 years; 78.0% White; 61.0% female). Adolescents' reports of SITB presence (vs. absence) and frequency, collected via EMA and retrospective interview over follow-up, were compared. Preliminary differences in SITB endorsement (presence/absence) were observed between reporting methods with more adolescents endorsing suicide ideation (SI; n = 30) and nonsuicidal self-injury (NSSI; n = 15) in EMA compared to retrospective interview (SI: n = 17; NSSI: n = 10). Reasons for withholding SITBs from EMA reports (gathered during a final qualitative interview) included not wanting to answer additional EMA questions and concerns about EMA-reporting consequences. There were no statistically significant differences in SITB frequency by report method. Further investigation is warranted in a larger sample to elucidate frequency patterns. Given the growing research using this method, these findings are important to help clarify the utility of EMA methods for studying SITBs in youth.