Sensory systems create neural representations of environmental stimuli and these representations can be associated with other stimuli through learning. Are spike patterns the neural representations that get directly associated with reinforcement during conditioning? In the moth Manduca sexta, we found that odor presentations that support associative conditioning elicited only one or two spikes on the odor’s onset (and sometimes offset) in each of a small fraction of Kenyon cells. Using associative conditioning procedures that effectively induced learning and varying the timing of reinforcement relative to spiking in Kenyon cells, we found that odor-elicited spiking in these cells ended well before the reinforcement was delivered. Furthermore, increasing the temporal overlap between spiking in Kenyon cells and reinforcement presentation actually reduced the efficacy of learning. Thus, spikes in Kenyon cells do not constitute the odor representation that coincides with reinforcement, and Hebbian spike timing–dependent plasticity in Kenyon cells alone cannot underlie this learning.

This study investigated psychotropic medication usage in two large, cohorts of people with autism spectrum disorder (ASD) throughout the calendar year 2014. The cohorts referred to individuals with commercial (employer-sponsored) and Medicaid insurance in the United States. We aimed to understand prescribing patterns of such medications across a wide age-range and in the presence/absence of other clinical and non-clinical characteristics, including psychiatric comorbidities. We described the prevalence and length of prescriptions by age, psychiatric comorbidity and overall. We also fitted multivariable logistic regression models to describe the relationship between treatments and subject characteristics simultaneously. Eighty percent of the identified population was male, although gender did not impact the odds of receiving medication. Medication use was strongly associated with age, increasing most rapidly before adulthood; generally plateauing thereafter. All psychiatric comorbidities studied also individually increased the chances of medication use, with epilepsy and ADHD having the highest associations in both the commercial (OR > 7) and Medicaid (OR around 12) cohorts. Those in non-capitated insurance plans, in foster care and white individuals also had increased odds of prescriptions. Overall, slightly more Medicaid enrollees received any psychotropic treatment (commercial: 64%, Medicaid: 69%). Nonetheless in both cohorts, a large proportion of individuals received treatment even without a diagnosis of any other psychiatric comorbidity (commercial: 31%, Medicaid: 33%). In summary, this report sheds new light on the latest patterns of psychiatric comorbidity profile and psycho-pharmacological treatment patterns in ASD Autism Res 2017, 10: 2037-2047. © 2017 International Society for Autism Research, Wiley Periodicals, Inc. LAY SUMMARY: this study identified a large number of children and adults in the US with autism spectrum disorder (autism) from employer-sponsored and government funded (Medicaid) health insurance data. Psychotropic medications were used by over two thirds of people, and four in ten people received two medications at the same time. The chances of receiving medication increased for individuals with other psychiatric conditions (e.g., ADHD), and also increased with age.

Summary In many species sensory stimuli elicit the oscillatory synchronization of groups of neurons. What determines the properties of these oscillations? In the olfactory system of the moth we found that odors elicited oscillatory synchronization through a neural mechanism like that described in locust and Drosophila. During responses to long odor pulses, oscillations suddenly slowed as net olfactory receptor neuron (ORN) output decreased; thus, stimulus intensity appeared to determine oscillation frequency. However, changing the concentration of the odor had little effect upon oscillatory frequency. Our recordings in vivo and computational models based on these results suggested the main effect of increasing odor concentration was to recruit additional, less well-tuned ORNs whose firing rates were tightly constrained by adaptation and saturation. Thus, in the periphery, concentration is encoded mainly by the size of the responsive ORN population, and oscillation frequency is set by the adaptation and saturation of this response.