Biology subjects

Mayer, J. L.

Publications and source records attributed to Mayer, J. L..

3 recordsLinked to original sources

bioRxiv2024

Visual objects refine head direction coding

Animals use visual objects to guide navigation-related behaviors, from hunting prey, to escaping predators, to exploring the world. However, little is known about where visual objects are encoded in the mouse brain or how they impact processing in the spatial navigation system. Using functional ultrasound imaging in mice, we conducted a brain-wide screen and identified brain areas that were preferentially activated by images of objects compared to scrambled versions of the same images. While visual cortical areas did not show a significant preference, regions associated with spatial navigation were preferentially activated by visual objects. Electrophysiological recordings in postsubiculum, the primary cortical area of the head direction (HD) system, further confirmed a preference for visual objects, which was present in both HD cells and fast-spiking interneurons. Finally, we found that visual objects dynamically modulated HD cells, selectively increasing firing rates of HD cells aligned with a visual landmarks direction, while decreasing activity in HD cells coding for other directions. These results reveal that visual objects refine population-level coding of head direction.

neuroscience↗

bioRxiv2023

Genetically- and spatially-defined basolateral amygdala neurons control food consumption and social interaction

The basolateral amygdala (BLA) contains discrete neuronal circuits that integrate positive or negative emotional information and drive the appropriate innate and learned behaviors. Whether these circuits consist of genetically-identifiable and anatomically segregated neuron types, is poorly understood. Also, our understanding of the response patterns and behavioral spectra of genetically-identifiable BLA neurons is limited. Here, we classified 11 glutamatergic BLA cell clusters and found that several of them were anatomically segregated in lateral versus basal amygdala, and anterior versus posterior regions of the BLA. Two of these BLA subpopulations innately responded to valence-specific, whereas one responded to mixed - aversive and social - cues. Positive-valence BLA neurons promoted normal feeding, while mixed selectivity neurons promoted fear learning and social interactions. These findings enhance our understanding of cell type diversity and spatial organization of the BLA and the role of distinct BLA populations in representing valence-specific and mixed stimuli. HighlightsO_LIClassification of molecularly-defined glutamatergic neuron types in mouse BLA with distinct spatial expression patterns. C_LIO_LIBLALypd1 neurons are positive-valence neurons innately responding to food and promoting normal feeding. C_LIO_LIBLAEtv1 neurons innately represent aversive and social stimuli. C_LIO_LIBLAEtv1 neurons promote fear learning and social interactions. C_LI

neuroscience↗

bioRxiv2022

Dynamic changes in gas solubility of xylem sap reiterate the enigma of plant water transport under negative pressure

Despite a long research history, we do not fully understand why plants are able to transport xylem sap under negative pressure without constant failure. Microbubble formation via direct gas entry is assumed to cause hydraulic failure, while the concentration of gas dissolved in xylem sap is traditionally supposed to be constant, following Henrys law. Here, the concentration of soluble gas in xylem sap was estimated in vivo using well-watered Citrus plants under varying levels of air temperature and photoperiodic exposure, and compared to modelled data. The gas concentration in xylem sap showed non-equilibrium curves, with a minimum over- or undersaturation of 5% compared to gas solubility based on Henrys law. A similar diurnal pattern was obtained from the gas concentration in the cut-open conduits and discharge tube, and oversolubility was strongly associated with decreasing xylem water potentials during transpiration. Although our model did not explain the daily changes in gas solubility for an anisobaric situation, oversolubility characterises nanoconfined liquids, such as sap inside cell walls. Thus, plants are able to transport sap under negative pressure with relatively high amounts of dissolved gas, providing them with a buffering capacity to prevent hydraulic failure, despite diurnal changes in pressure and temperature.

plant biology↗