Motor neurons generate pose-targeted movements via proprioceptive sculpting

Motor neurons are the final common pathway1 through which the brain controls movement of the body, forming the basic elements from which all movement is composed. Yet how a single motor neuron contributes to control during natural movement remains unclear. Here we anatomically and functionally characterize the individual roles of the motor neurons that control head movement in the fly, Drosophila melanogaster. Counterintuitively, we find that activity in a single motor neuron rotates the head in different directions, depending on the starting posture of the head, such that the head converges towards a pose determined by the identity of the stimulated motor neuron. A feedback model predicts that this convergent behaviour results from motor neuron drive interacting with proprioceptive feedback. We identify and genetically2 suppress a single class of proprioceptive neuron3 that changes the motor neuron-induced convergence as predicted by the feedback model. These data suggest a framework for how the brain controls movements: instead of directly generating movement in a given direction by activating a fixed set of motor neurons, the brain controls movements by adding bias to a continuing proprioceptive-motor loop.

Neurogenetic dissection of the Drosophila lateral horn reveals major outputs, diverse behavioural functions, and interactions with the mushroom body

Animals exhibit innate behaviours to a variety of sensory stimuli including olfactory cues. In Drosophila, one higher olfactory centre, the lateral horn (LH), is implicated in innate behaviour. However, our structural and functional understanding of the LH is scant, in large part due to a lack of sparse neurogenetic tools for this region. We generate a collection of split-GAL4 driver lines providing genetic access to 82 LH cell types. We use these to create an anatomical and neurotransmitter map of the LH and link this to EM connectomics data. We find ~30% of LH projections converge with outputs from the mushroom body, site of olfactory learning and memory. Using optogenetic activation, we identify LH cell types that drive changes in valence behavior or specific locomotor programs. In summary, we have generated a resource for manipulating and mapping LH neurons, providing new insights into the circuit basis of innate and learned olfactory behavior.

Implementation of Oral Health Screening and Referral Guidelines in Primary Health Care

Objectives:

To determine the oral health screening and referral practices of pediatric providers, their adherence to American Academy of Pediatrics oral health guidelines, and barriers to adherence.

Methods:

Providers in 10 pediatric practices participating in the North Carolina Quality Improvement Initiative, funded by the Child Health Insurance Program Reauthorization Act of 2009, were asked to complete a 91-item questionnaire. Questions on risk assessment and referral practices were based on those recommended by the American Academy of Pediatrics. Adherence to oral health guidelines was assessed by practitioners’ evaluation of 4 vignettes presenting screening results for an 18-mo-old child with different levels of risk and caries status. Respondents chose referral recommendations assuming adequate and inadequate dentist workforces. Logit models determined the association between barriers specified in Cabana’s framework and adherence (count of 6 to 8 adherent vignettes vs. 0 to 5).

Results:

Of 72 eligible providers, 53 (74%) responded. Almost everyone (98.1%) screened for dental problems; 45.2% referred in at least half of well-child visits. Respondents were aware of oral health guidelines, expressed strong agreement with them, and reported confidence in providing preventive oral health services. Yet they underreferred by an average of 42% per vignette for the 7 clinical vignette-workforce scenarios requiring an immediate referral. Frequently cited barriers were providers’ beliefs that 1) parents are poorly motivated to seek dental care, 2) oral health counseling has a small effect on parent behaviors, 3) there is a shortage of dentists in their community who will see infants and toddlers, and 4) information systems to support referrals are insufficient.

Conclusion:

Pediatric clinicians’ beliefs lead to a conscious decision not to refer many patients, even when children should be referred.

Knowledge Transfer Statement:

Evidence suggests that the primary care–dental referral process needs improvement. This study identifies barriers to delivering recommended preventive oral health services in pediatrics. The information can be used to improve the screening and referral process and, thus, the quality of preventive oral health services provided in primary care. Results also can guide researchers on the selection of interventions that need testing and might close gaps in the referral process and improve access to dental care.

Morphine inhibits the release of tumor necrosis factor in human peripheral blood mononuclear cell cultures

Opiates modulate a variety of immune responses of peripheral blood mononuclear cells (PBMC). When PBMC were treated with morphine for 24 h, cells released less (P < 0.05) bioactive TNF, a cytokine important in host defense, in the following 24-h incubation period when stimulated with lipopolysaccharide and phytohemagglutinin. Morphine alone did not significantly alter the release of TNF from PBMC cultures. Pretreatment of PBMC cultures for 1 h with naloxone blocked (P < 0.05) the inhibitory effect of morphine on the release of TNF upon stimulation with phytohemagglutinin, but not with lipopolysaccharide, suggesting the involvement of an opioid receptor. The mechanism of morphine-induced suppression of TNF release appears to be counteracted by the effect of this opiate on the release of transforming growth factor (TGF)-beta, since antibodies to this immunoregulatory cytokine further enhanced morphine-related inhibition of TNF release. Taken together, these findings indicate that morphine suppresses the release of bioactive TNF from PBMC and that TGF-beta plays a modulatory role in this inhibitory process.

Cytokine release from microglia: differential inhibition by pentoxifylline and dexamethasone

Cytokines have been implicated in the pathogenesis of gram-negative bacterial meningitis. The effects of pentoxifylline and dexamethasone on the release of tumor necrosis factor (TNF), interleukin (IL)-1, and IL-6 from primary murine microglial cell cultures were explored using bioassays. When added concomitantly with lipopolysaccharide, pentoxifylline blocked the release of TNF and IL-1 but not IL-6, while dexamethasone inhibited the release of TNF and IL-6. After a 2-h exposure of microglia to lipopolysaccharide, pentoxifylline but not dexamethasone still inhibited the release of TNF. Release of TNF was enhanced 20-fold by priming of the microglia with interferon-gamma; only pentoxifylline blocked the priming effect of interferon-gamma on TNF release. These results demonstrate that pentoxifylline and dexamethasone differentially regulate the release of cytokines in microglial cell cultures and provide potential insight into their role in the treatment of gram-negative bacterial meningitis.

Immunologically mediated fatigue: a murine model

Chronic fatigue syndrome (CFS) is an idiopathic disorder in which the chief symptoms is profound fatigue. To explore the relationship between immune stimulation and fatigue, we developed a murine model for quantifying fatigue: reduction in voluntary running and delayed initiation of grooming after swimming. Inoculation of female BALB/c mice with Corynebacterium parvum antigen or the relatively avirulent Me49 strain of Toxoplasma gondii induced fatigue: baseline running reduced to less than 50 and 30% for 8 and 14 days, respectively, and delayed initiation of grooming after swimming in both immunologically stimulated groups. A threefold evaluation of serum transforming growth factor-beta levels, a cytokine increased in CFS patients, was found in fatigued C. parvum- and T. gondii-inoculated mice. This murine model appears promising for investigation of the pathogenesis of immunologically mediated fatigue.