Proboscis conditioning experiments with honeybees, Apis mellifera caucasica, with butyric acid and DEET mixture as conditioned and unconditioned stimuli

Three experiments are described investigating whether olfactory repellents DEET and butyric acid can support the classical conditioning of proboscis extension in the honeybee, Apis mellifera caucasica (Hymenoptera: Apidae). In the first experiment DEET and butyric acid readily led to standard acquisition and extinction effects, which are comparable to the use of cinnamon as a conditioned stimulus. These results demonstrate that the odor of DEET or butyric acid is not intrinsically repellent to honey bees. In a second experiment, with DEET and butyric acid mixed with sucrose as an unconditioned stimulus, proboscis conditioning was not established. After several trials, few animals responded to the unconditioned stimulus. These results demonstrate that these chemicals are gustatory repellents when in direct contact. In the last experiment a conditioned suppression paradigm was used. Exposing animals to butyric acid or DEET when the proboscis was extended by direct sucrose stimulation or by learning revealed that retraction of the proboscis was similar to another novel odor, lavender, and in all cases greatest when the animal was not permitted to feed. These results again demonstrate that DEET or butyric acid are not olfactory repellents, and in addition, conditioned suppression is influenced by feeding state of the bee.Peer reviewedPsychologyZoolog

Seduced by System: Edmund Burke's Aesthetic Embrace of Adam Smith's Philosophy

No abstract available

Novel genetic loci associated with hippocampal volume

The hippocampal formation is a brain structure integrally involved in episodic memory, spatial navigation, cognition and stress responsiveness. Structural abnormalities in hippocampal volume and shape are found in several common neuropsychiatric disorders. To identify the genetic underpinnings of hippocampal structure here we perform a genome-wide association study (GWAS) of 33,536 individuals and discover six independent loci significantly associated with hippocampal volume, four of them novel. Of the novel loci, three lie within genes (ASTN2, DPP4 and MAST4) and one is found 200 kb upstream of SHH. A hippocampal subfield analysis shows that a locus within the MSRB3 gene shows evidence of a localized effect along the dentate gyrus, subiculum, CA1 and fissure. Further, we show that genetic variants associated with decreased hippocampal volume are also associated with increased risk for Alzheimer's disease (rg =-0.155). Our findings suggest novel biological pathways through which human genetic variation influences hippocampal volume and risk for neuropsychiatric illness

Data from: Genetic and lifestyle risk factors for MRI-defined brain infarcts in a population-based setting

Objective: We explored genetic and lifestyle risk factors of MRI-defined brain infarcts (BI) in large population-based cohorts. Methods: We performed meta-analyses of genome-wide association studies (GWAS) and examined associations of vascular risk factors and their genetic risk scores (GRS) with MRI-defined BI and a subset of BI, namely small sub-cortical BI (SSBI), in eighteen population-based cohorts (N=20,949) from five ethnicities (3,726 with BI, 2,021 with SSBI). Top loci were followed up in seven population-based cohorts (N=6,862, 1,483 with BI, 630 with SBBI), and tested associations with related phenotypes including ischemic stroke and pathologically-defined BI. Results: The mean prevalence was 17.7% for BI and 10.5% for SSBI, steeply rising after age 65. Two loci showed genome-wide significant association with BI: FBN2, P=1.77×10-8 and LINC00539/ZDHHC20, P=5.82×10-9. Both have been associated with blood pressure (BP) related phenotypes, but did not replicate in the smaller follow-up sample nor show associations with related phenotypes. Age and sex-adjusted associations with BI and SSBI were observed for BP traits (P-value for BI, P[BI]=9.38×10-25; P[SSBI]=5.23×10-14 for hypertension), smoking (P[BI]=4.4×10-10; P[SSBI]=1.2×10-4), diabetes (P[BI]=1.7×10-8; P[SSBI]=2.8×10-3), previous cardiovascular disease (P[BI]=1.0×10-18; P[SSBI]=2.3×10-7), stroke (P[BI]=3.9×10-69; P[SSBI]=3.2×10-24), and MRI-defined white matter hyperintensity burden (P[BI]=1.43×10-157; P[SSBI]=3.16×10-106), but not with body-mass-index or cholesterol. GRS of BP traits were associated with BI and SSBI (P≤0.0022), without indication of directional pleiotropy. Conclusions: In this multi-ethnic GWAS meta-analysis, including over 20,000 population-based participants, we identified genetic risk loci for BI requiring validation once additional large datasets become available. High BP, including genetically determined, was the most significant modifiable, causal risk factor for BI