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Stahlberg, M. A.

Publications and source records attributed to Stahlberg, M. A..

2 recordsLinked to original sources

A Proof-of-Principle of Nanoscale Optogenetics

Optogenetics has revolutionized the study of circuit function in the brain, by allowing activation of specific ensembles of neurons by light. However, this technique has not yet been exploited extensively at the subcellular level. Here we propose a novel focal stimulation approach using STED/RESOLFT-like illumination, whereby switchable light-gated channels are focally activated by a laser beam of one wavelength and deactivated by an overlapping donut-shaped beam of a different wavelength, confining activation to a center focal region. We demonstrate the utility of current optogenetic tools to achieve highly focal depolarization using this method and further examine a proof-of-principle of nanoscale optogenetic activation using an initial macroscale approach. When employed at the nanoscale, this approach will allow unprecedented optogenetic control of nanodomains within cells.

neuroscience

Visualizing BDNF cell-to-cell transfer reveals astrocytes are the primary recipient of neuronal BDNF

Brain-derived neurotrophic factor (BDNF) is essential for neuronal growth, differentiation, and synaptic plasticity. Although the release and effects of BDNF have been well-studied separately, the transfer of BDNF between cells has not been investigated. Using a four-fluorophore imaging approach to identify both the cell of origin and target cells, we quantified the transfer of BDNF. Surprisingly, we found that astrocytes are the main recipient of neuronally expressed BDNF. We further found that astrocytes specifically take up mature (not pro) BDNF released by neurons. Over-expression of TrkB in neurons redirects released BDNF from astrocytes to neurons, indicating that TrkB levels determine neuronal versus astrocytic BDNF uptake. Increased neuronal activity further increased astrocytic (but not neuronal) uptake of neuronally expressed BDNF. Finally, we demonstrate that astrocytes are not simply a sink for excess BDNF, but that BDNF taken up by astrocytes mediates physiological effects on the astrocytic population by increasing astrocytic territory.

neuroscience