Test‐retest reliability of amygdala response to emotional faces

In the current study, we evaluated the test‐retest reliability of amygdala response using an emotional face‐matching task that has been widely used to examine pathophysiology and treatment mechanisms in psychiatric populations. Activation within the fusiform face area ( FFA ) was also examined. Twenty‐seven healthy volunteers completed a variation of the face‐matching paradigm developed by Hariri et al. (2000) at two time points approximately 90 days apart. Estimates of test‐retest reliability of amygdala response to fearful faces were moderate, whereas angry and happy faces showed poor reliability. Test‐retest reliability of the FFA was moderate to strong, regardless of facial affect. Collectively, these findings indicate that the reliability of the BOLD MR signal in the amygdala varies substantially by facial affect. Efforts to improve measurement precision, enlarge sample sizes, or increase the number of assessment occasions seem warranted.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/100342/1/psyp12129.pd

Reward dysfunction in major depression: Multimodal neuroimaging evidence for refining the melancholic phenotype

Reward dysfunction is thought to play a core role in the pathophysiology of major depressive disorder (MDD). Event-related potential (ERP) and functional magnetic resonance imaging (fMRI) studies have identified reward processing deficits in MDD, but these methods have yet to be applied together in a single MDD sample. We utilized multimodal neuroimaging evidence to examine reward dysfunction in MDD. Further, we explored how neurobiological reward dysfunction would map onto subtypes of MDD. The feedback negativity (FN), an ERP index of reward evaluation, was recorded in 34 unmedicated depressed individuals and 42 never-depressed controls during a laboratory gambling task. Ventral striatal (VS) activation to reward was recorded in a separate fMRI session, using an identical task, among a subgroup of 24 depressed individuals and a comparison group of 18 non-depressed controls. FN amplitude was blunted in MDD. This effect was driven by a MDD subgroup characterized by impaired mood reactivity to positive events, a core feature of melancholic MDD. A similar pattern was observed for VS activation, which was also blunted among the MDD subgroup with impaired mood reactivity. Neither FN amplitude nor VS activation were related to the full, DSM-defined melancholic or atypical MDD subtypes. Across the MDD sample, FN amplitude and VS activation were correlated, indicating convergence across methods. These results indicate that not all MDD is characterized by reward dysfunction, and that there is meaningful heterogeneity in reward processing within MDD. The current study offers neurobiological evidence that impaired mood reactivity is a key phenotypic distinction for subtyping MDD, and further suggests that the existing melancholic phenotype may require further refinement

Grassy–herbaceous land moderates regional climate effects on honey bee colonies in the Northcentral US

The lack of seasonally sustained floral resources (i.e. pollen and nectar) is considered a primary global threat to pollinator health. However, the ability to predict the abundance of flowering resources for pollinators based upon climate, weather, and land cover is difficult due to insufficient monitoring over adequate spatial and temporal scales. Here we use spatiotemporally distributed honey bee hive scales that continuously measure hive weights as a standardized method to assess nectar intake. We analyze late summer colony weight gain as the response variable in a random forest regression model to determine the importance of climate, weather, and land cover on honey bee colony productivity. Our random forest model predicted resource acquisition by honey bee colonies with 71% accuracy, highlighting the detrimental effects of warm, wet regions in the Northcentral United States on nectar intake, as well as the detrimental effect of years with high growing degree day accumulation. Our model also predicted that grassy–herbaceous natural land had a positive effect on the summer nectar flow and that large areas of natural grassy–herbaceous land around apiaries can moderate the detrimental effects of warm, wet climates. These patterns characterize multi-scale ecological processes that constrain the quantity and quality of pollinator nutritional resources. That is, broad climate conditions constrain regional floral communities, while land use and weather act to further modify the quantity and quality of pollinator nutritional resources. Observing such broad-scale trends demonstrates the potential for utilizing hive scales to monitor the effects of climate change on landscape-level floral resources for pollinators. The interaction of climate and land use also present an opportunity to manage for climate-resilient landscapes that support pollinators through abundant floral resources under climate change

Ecological momentary assessment as a measurement tool in depression trials

We used ecological momentary assessment (EMA) to track symptoms during a clinical trial. Thirty-six participants with major depressive disorder (MDD) and MADRS scores ≥20 were enrolled in a nonrandomized 6-week open-label trial of commercially available antidepressants. Twice daily, a mobile device prompted participants to self-report the 6 items of the HamD6 sub-scale derived from the Hamilton rating scale for depression (HamD17). Morning EMA reports asked “how do you feel now” whereas evening reports gathered a full-day impression. Clinicians who were blinded to the EMA data rated the MADRS, HamD17 and HamD6 at screen, baseline and weeks 2,4, and 6. Hierarchical linear modeling (HLM) examined the course of the EMA assessments and convergence between EMA scores and clinician ratings. HLM analyses revealed strong correlations between AM and PM EMA derived HamD6 scores and revealed significant improvements over time. EMA improvements were significantly correlated with the clinician rated HamD6 scores at endpoint and predicted clinician rated HamD6 score changes from baseline to endpoint (p < .001). There was a large correlation between EMA and clinician derived HamD6 scores at each in-person assessment after baseline. Treatment response defined by EMA matched the clinician rated HamD6 treatment responses in 33 of 36 cases (91.7%). EMA derived symptom scores appear to be efficient and valid measures to track daily symptomatic change in clinical trials and may provide more accurate measures of symptom severity than the episodic “snapshots” that are currently used as clinical outcomes. These findings support further investigation of EMA for assessment in clinical trials. •Ecological momentary assessment (EMA) tracked symptoms in an MDD clinical trial.•Participants were prompted twice daily to self-report symptoms from the HamD6 scale.•HLM revealed strong correlations between EMA HamD6 and clinician HamD6 scores.•The EMA scores predicted clinician score changes at endpoint (p < .001).•33 of 36 EMA HamD6 scores (91.7%) matched clinician rated HamD6 treatment responses