Making Sense of the Multiplicity and Dynamics of Navigational Codes in the Brain.

Since the discovery of conspicuously spatially tuned neurons in the hippocampal formation over 50 years ago, characterizing which, where, and how neurons encode navigationally relevant variables has been a major thrust of navigational neuroscience. While much of this effort has centered on the hippocampal formation and functionally-adjacent structures, recent work suggests that spatial codes, in some form or another, can be found throughout the brain, even in areas traditionally associated with sensation, movement, and executive function. In this review, we highlight these unexpected results, draw insights from comparison of these codes across contexts, regions, and species, and finally suggest an avenue for future work to make sense of these diverse and dynamic navigational codes

Conserved molecular components for pollen tube reception and fungal invasion

During sexual reproduction in flowering plants such as Arabidopsis, a tip-growing pollen tube (PT) is guided to the synergid cells of the female gametophyte, where it bursts and releases the two sperm. Here we show that PT reception and powdery mildew (PM) infection, which involves communication between a tip-growing hypha and a plant epidermal cell, share molecular components. NORTIA (NTA), a member of the MLO family originally discovered in the context of PM resistance, and FERONIA (FER), a receptor-like kinase, both control PT reception in synergids. Homozygous fer mutants also display PM resistance, revealing a new function for FER and suggesting that conserved components, such as FER and distinct MLO proteins, are involved in both PT reception and PM infection