Medical student burnout: Impact of the gap year in burnout prevention.

OBJECTIVE: Burnout is a common response to stress and is pervasive among medical students. An increasing proportion of students are taking "gap years" following undergraduate education and before matriculation to medical school. This study evaluates rates of and risk factors for burnout, with a particular focus on students who took gap years. METHODS: Burnout was measured utilizing the abbreviated Maslach Burnout Inventory. The primary independent variable was whether a student took one or more gap years prior to medical school matriculation. Other variables included age, gender, year in medical school, choice in specialty, and status in a combined baccalaureate-M.D. PROGRAM: Bivariate and multivariate regression was performed to elucidate relationships between student-level variables and burnout. RESULTS: A total of 31.4% of respondents were found to be experiencing high levels of burnout. In multivariate analysis, gap years were independently associated with lower levels of burnout (p = 0.041). Further, burnout decreased in a stepwise fashion with students who took 0 (p = 0.350), 1 (p = 0.192), and 2+ (p = 0.048) gap years. CONCLUSIONS: Students taking gap years exhibited significantly lower levels of burnout than those who did not. Efforts should be made in pre-medical and medical school curricula to better support students in their paths to medical school.

Changes in Olfactory Sensory Neuron Physiology and Olfactory Perceptual Learning After Odorant Exposure in Adult Mice.

The adult olfactory system undergoes experience-dependent plasticity to adapt to the olfactory environment. This plasticity may be accompanied by perceptual changes, including improved olfactory discrimination. Here, we assessed experience-dependent changes in the perception of a homologous aldehyde pair by testing mice in a cross-habituation/dishabituation behavioral paradigm before and after a week-long ester-odorant exposure protocol. In a parallel experiment, we used optical neurophysiology to observe neurotransmitter release from olfactory sensory neuron (OSN) terminals in vivo, and thus compared primary sensory representations of the aldehydes before and after the week-long ester-odorant exposure in individual animals. Mice could not discriminate between the aldehydes during pre-exposure testing, but ester-exposed subjects spontaneously discriminated between the homologous pair after exposure, whereas home cage control mice cross-habituated. Ester exposure did not alter the spatial pattern, peak magnitude, or odorant-selectivity of aldehyde-evoked OSN input to olfactory bulb glomeruli, but did alter the temporal dynamics of that input to make the time course of OSN input more dissimilar between odorants. Together, these findings demonstrate that odor exposure can induce both physiological and perceptual changes in odor processing, and suggest that changes in the temporal patterns of OSN input to olfactory bulb glomeruli could induce differences in odor quality.

Odor-specific, olfactory marker protein-mediated sparsening of primary olfactory input to the brain after odor exposure.

Long-term plasticity in sensory systems is usually conceptualized as changing the interpretation of the brain of sensory information, not an alteration of how the sensor itself responds to external stimuli. However, here we demonstrate that, in the adult mouse olfactory system, a 1-week-long exposure to an artificially odorized environment narrows the range of odorants that can induce neurotransmitter release from olfactory sensory neurons (OSNs) and reduces the total transmitter release from responsive neurons. In animals heterozygous for the olfactory marker protein (OMP), this adaptive plasticity was strongest in the populations of OSNs that originally responded to the exposure odorant (an ester) and also observed in the responses to a similar odorant (another ester) but had no effect on the responses to odorants dissimilar to the exposure odorant (a ketone and an aldehyde). In contrast, in OMP knock-out mice, odorant exposure reduced the number and amplitude of OSN responses evoked by all four types of odorants equally. The effect of this plasticity is to preferentially sparsen the primary neural representations of common olfactory stimuli, which has the computational benefit of increasing the number of distinct sensory patterns that could be represented in the circuit and might thus underlie the improvements in olfactory discrimination often observed after odorant exposure (Mandairon et al., 2006a). The absence of odorant specificity in this adaptive plasticity in OMP knock-out mice suggests a potential role for this protein in adaptively reshaping OSN responses to function in different environments.