Faculty Bibliography

This review summarizes the available literature on the intersection of adolescent cannabis use and sleep disturbances, along with interventions for adolescent cannabis users who suffer sleep impairments. Adolescents are susceptible to various sleep disorders, which are often exacerbated by the use of substances such as cannabis. The relationship between cannabis and sleep is bidirectional. Interventions to improve sleep impairments among adolescent cannabis users to date have demonstrated limited efficacy, although few studies indicating the benefits of behavioral interventions-such as Cognitive Behavior Therapy for Insomnia or Mindfulness Based Stress Reduction-appear promising in the treatment of sleep disorders, which are present for users of cannabis. Further research is necessary to elucidate the precise mechanisms by which cannabis use coexists with sleep impairments, along with effective interventions for those users who suffer sleep difficulties.

Human olfaction is sensitive but poorly encoded by language. A new study comparing horticulturalists and hunter-gatherers suggests that the strength of odor language is dependent on life-style. This work may stimulate olfactory research at the crossroads between biology and culture.

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A widely held view is that top-down modulation of sensory information relies on an amodal control network that acts through the thalamus to regulate incoming signals. Olfaction lacks a direct thalamic projection, which suggests that it may differ from other modalities in this regard. We investigated the late positive complex (LPC) amplitudes of event-related potentials (ERP) from 28 participants, elicited by intensity-matched olfactory, auditory and visual stimuli, during a condition of focused attention, a neutral condition, and a condition in which stimuli were to be actively ignored. Amplitudes were largest during the attend condition, lowest during the ignore condition, with the neutral condition in between. A Bayesian analysis resulted in strong evidence for similar effects of task across sensory modalities. We conclude that olfaction, despite its unique neural projections, does not differ from audition and vision in terms of task-dependent neural modulation of the LPC.

We argue that subjective emotional experience, the feeling, is the essence of an emotion, and that objective manifestations in behavior and in body or brain physiology are, at best, indirect indicators of these inner experiences. As a result, the most direct way to assess conscious emotional feelings is through verbal self-report. This creates a methodological barrier to studies of conscious feelings in animals. While the behavioral and physiological responses are not "˜emotions,"™ they contribute to emotions indirectly, and sometimes profoundly. Whether non-verbal animals have emotional experiences is a difficult, maybe impossible, question to answer in the positive or negative. But because behavioral and physiological responses are important contributors to emotions, and the circuits underlying these are highly conserved, studies of animals have an important role in understanding how emotions are expressed and regulated in the brain. Conflation of circuits that directly give rise to conscious emotional feelings with circuits that indirectly influences these conscious feelings has hampered progress in efforts to understand emotions, and also to understand and to develop treatments for emotional disorders. Recognition of differences in these circuits will allow research in animals to have a lasting impact on understanding of human emotions as research goes forward.

Infant gross motor development is vital to adaptive function and predictive of both cognitive outcomes and neurodevelopmental disorders. However, little is known about neural systems underlying the emergence of walking and general gross motor abilities. Using resting state fcMRI, we identified functional brain networks associated with walking and gross motor scores in a mixed cross-sectional and longitudinal cohort of infants at high and low risk for autism spectrum disorder, who represent a dimensionally distributed range of motor function. At age 12 months, functional connectivity of motor and default mode networks was correlated with walking, whereas dorsal attention and posterior cingulo-opercular networks were implicated at age 24 months. Analyses of general gross motor function also revealed involvement of motor and default mode networks at 12 and 24 months, with dorsal attention, cingulo-opercular, frontoparietal, and subcortical networks additionally implicated at 24 months. These findings suggest that changes in network-level brain-behavior relationships underlie the emergence and consolidation of walking and gross motor abilities in the toddler period. This initial description of network substrates of early gross motor development may inform hypotheses regarding neural systems contributing to typical and atypical motor outcomes, as well as neurodevelopmental disorders associated with motor dysfunction.