Biology subjects

Nilssen, E. S.

Publications and source records attributed to Nilssen, E. S..

3 recordsLinked to original sources

bioRxiv2026

Dispersal behavior in a cold-water coral is orchestrated via stage and species-specific physiology.

Corals form important ecosystems that serve as habitat for numerous marine species. Being sessile, adult corals are exposed to changing environments without the means to relocate. Species dispersal is therefore restricted to the motile larval lifestage. How do microscopic larvae achieve reliable dispersal and conquest of novel habitats under time pressure and unpredictable environmental conditions? Here we show an unexpected diversity of behaviors in the cold-water coral Lophelia pertusa. Anatomical and behavioral changes of coral planula promote a change from neutral, passive buoyancy in the dispersal phase, to active swimming and search behavior during competency. As lipids are metabolized and sensory abilities develop, the coral larvae drastically change their motility patterns. Comparative analysis with a poorly dispersing, lecithotrophic anthozoan larvae reveals that developmentally timed sensory integration is conserved between species, but the behavioral modes and sensory responses are adapted to their particular ecology.

developmental biology↗

bioRxiv2022

Long-range inhibitory axons from medial entorhinal cortex target lateral entorhinal neurons projecting to the hippocampus

The functionally different lateral entorhinal cortex (LEC) and medial entorhinal cortex (MEC) are strongly interconnected. The role of this interconnectivity in view of their functional differences is not known. Here we provide details on a circuit that directly connects MEC to neurons in the superficial layers of LEC. Using a combination of anatomical tracing experiments and in vitro electrophysiological recordings in the mouse, we report that axons from MEC somatostatin-expressing GABAergic neurons densely distribute in layer I of LEC, where they drive strong and near selective inhibition of principal neurons in layer IIa. This inhibitory pathway is accompanied by MEC glutamatergic axons that innervate multiple layers of LEC and preferentially synapse onto principal neurons in layers IIb and III rather than principal neurons in layer IIa. These findings indicate that excitatory and inhibitory projections from MEC may separately regulate the activity of different populations of hippocampal-projecting principal neurons in LEC.

neuroscience↗

bioRxiv2020

Local circuits of layer Vb-to-Va neurons mediate hippocampal-cortical outputs in lateral but not in medial entorhinal cortex

The entorhinal cortex, in particular neurons in layer V, allegedly mediate transfer of information from the hippocampus to the neocortex, underlying long-term memory. Recently, this circuit has been shown to comprise a hippocampal output recipient layer Vb and a cortical projecting layer Va. With the use of in vitro electrophysiology in transgenic mice specific for layer Vb, we assessed the presence of the thus necessary connection from layer Vb-to-Va in the functionally distinct medial (MEC) and lateral (LEC) subdivisions; MEC, particularly its dorsal part, processes allocentric spatial information, whereas the corresponding part of LEC processes information representing elements of episodes. Using identical experimental approaches, we show that connections from layer Vb-to-Va neurons are more effective in LEC compared with dorsal MEC. This indicates that the hippocampal-cortex output circuit is more effective in LEC, suggesting that episodic systems-consolidation may use LEC-derived information more than allocentric spatial information from MEC.

neuroscience↗