Biology subjects

Harris, J.

Publications and source records attributed to Harris, J..

3 recordsLinked to original sources

bioRxiv2018

Connectional architecture of a mouse hypothalamic circuit node controlling social behavior

Type 1 Estrogen receptor-expressing neurons in the ventrolateral subdivision of the ventromedial hypothalamus (VMHvlEsr1) play a causal role in the control of social behaviors including aggression. Here we use six different viral-genetic tracing methods to map the connectional architecture of VMHvlEsr1 neurons. These data reveal a high level of input convergence and output divergence (\"fan-in/fan-out\") from and to over 30 distinct brain regions, with a high degree (~90%) of recurrence. Unlike GABAergic populations in other hypothalamic nuclei controlling feeding and parenting behavior, VMHvlEsr1 glutamatergic neurons collateralize to multiple targets. However, we identify two anatomically distinct subpopulations with anterior vs. posterior biases in their collateralization patterns. Surprisingly, these two subpopulations receive indistinguishable inputs. These studies suggest an overall system architecture in which an anatomically feed-forward sensory-to-motor processing stream is integrated with a dense, highly recurrent central processing circuit. This architecture differs from the \"brain-inspired\" feed-forward circuits used in certain types of artificial intelligence networks.\n\nSIGNIFICANCEHow the cellular heterogeneity of brain nuclei maps onto circuit connectivity, the relationship of this anatomical mapping to behavioral function, and whether there are general principles underlying this relationship, remains poorly understood. Here we systematically map the connectivity of estrogen receptor-1-expressing neurons in the ventromedial hypothalamus (VMHvlEsr1), which control aggression and other social behaviors. We find that a relatively sparse, anatomically feed-forward sensory-to-motor processing stream is integrated with a dense, highly recurrent central processing circuit. Further, the VMHvl contains at least two subpopulations of Esr1+ neurons with different cell body characteristics and locations, with distinct patterns of collateralization to downstream targets. Nevertheless, these projection-defined subpopulations receive similar inputs. This input-output organization appears distinct from those described in other hypothalamic nuclei.

neuroscience↗

bioRxiv2018

Quality circles for quality improvement in primary health care: their effectiveness, gaps of knowledge, origins and significance - a scoping review

BackgroundQuality circles, or similarly structured small groups in primary health care, such as peer review groups, consist of 6 to 12 professionals from the same background who meet regularly to improve their standard practice. This paper reports the results from a scoping search performed to clarify possible effectiveness, knowledge gaps, underlying concepts and significance.\n\nObjectivesTo gain insight into knowledge gaps and understanding of the effectiveness, origins and significance of quality circles.\n\nMethodsA search strategy was developed starting with quality circle in PubMed and the index terms from those articles revealed were then used as search terms to identify further papers. Repeating this process in collaboration with a librarian, search strings relating to quality circles were built, and databases searched up to December 2017. Any paper on structured quality circles or related small group work in primary health care was included when relevant to the objectives.\n\nResultsFrom 11973 citations, 82 background papers and 58 key papers were identified, in addition to 12 books and 10 websites. 19 studies, one paper summarizing three studies and one systematic review suggest that quality circles can be effective in behaviour change, though with varying effect sizes. Quality circles and their techniques are complex, as they are not standardized, and changes seem to depend on the topic and context, which requires further research into how and why they work in order to improve them. From their origins in industry, they are now used in primary health care in many countries for continuous medical education, continuous professional development and quality improvement.\n\nConclusionThe evidence on quality circles indicates that they can successfully change general practitioner behaviour. As they are a complex intervention, theory-driven research approaches are needed to understand and improve their effectiveness. This is of major importance because they play an important role in quality improvement in primary health care in many countries.

scientific communication and education↗

bioRxiv2018

Classification of electrophysiological and morphological types in mouse visual cortex

Understanding the diversity of cell types in the brain has been an enduring challenge and requires detailed characterization of individual neurons in multiple dimensions. To profile morpho-electric properties of mammalian neurons systematically, we established a single cell characterization pipeline using standardized patch clamp recordings in brain slices and biocytin-based neuronal reconstructions. We built a publicly-accessible online database, the Allen Cell Types Database, to display these data sets. Intrinsic physiological and morphological properties were measured from over 1,800 neurons from the adult laboratory mouse visual cortex. Quantitative features were used to classify neurons into distinct types using unsupervised methods. We establish a taxonomy of morphologically- and electrophysiologically-defined cell types for this region of cortex with 17 e-types and 35 m-types, as well as an initial correspondence with previously-defined transcriptomic cell types using the same transgenic mouse lines.

neuroscience↗