How our brains keep track of where we are in the world (Journal of Neuroscience)

Libraries, supermarkets, classrooms…the world is full of places that look very similar, and yet our brains always seem to keep track of where we are. In a new study published in the Journal of Neuroscience, researchers at Princeton University and Ohio State University have uncovered one way in which the brain does this.

Similar-looking places can be distinguished from each other because of differences in what we experience when navigating to them. As we head toward a destination, our brains catalogue details such as other nearby buildings, the look of the doorway, even the people nearby.

The researchers discovered that the parahippocampal cortex, a part of the visual system that analyzes the current scene in front of us, also incorporates the details leading up to the scene, or its “temporal context.” As a result, even when two scenes look identical, we create different memory traces for them when their temporal contexts are different. Ultimately, this can help our brains to keep track of where we are in the world.

Learn more about Nicholas Turk-Browne‘s research at Princeton University.

Journal Citation: Turk-Browne NB, Simon MG, Sederberg PB. Scene representations in parahippocampal cortex depend on temporal context.  J Neurosci. 2012 May 23;32(21):7202-7.

Water filters made with copper could remove bacteria at lower cost (Journal of Applied Physics)

Porous ceramic water filters are often coated with colloidal silver, which prevents the growth of microbes trapped in the micro- and nano-scale pores of the filter. Other metals such as copper and zinc have also been shown to exhibit anti-microbial activity. Princeton University’s Wole Soboyejo and colleagues used atomic force microscopy (AFM) measurements to study the adhesion interaction between Escherichia coli (E. coli) bacteria and colloidal silver, silver nanoparticles, and copper nanoparticles, as well as the interactions of the bacteria and the three different types of metal to porous clay-based ceramic surfaces.

As reported in the May 24, 2012 issue of Journal of Applied Physics, of the three antimicrobial metals studied the silver nanoparticles had the highest affinity for E. coli bacteria. The colloidal silver had the highest affinity for a porous ceramic surface and is therefore the least likely to leach into the filtrate. However, since the adhesion between colloidal silver and E. coli is in the same range as the adhesion between copper and the bacteria, copper may have potential as a less expensive disinfectant coating for ceramic water filters.

Source: American Institute of Physics

Twenty-first-century projections of North Atlantic tropical storms from CMIP5 models (Nature Climate Change)

Efforts to predict North Atlantic hurricane activity should focus on improving the ability of global climate models to capture the processes that control patterns of sea surface temperature change through better modeling of cloud physics, atmospheric convection, oceanic processes, the role of aerosols, and overall improvements in spatial resolution of the models, according to a new study by Gabriele Villarini, a postdoctoral research associate in the Department of Civil and Environmental Engineering at Princeton University, and Gabriel A. Vecchi, a scientist at the U.S. National Oceanic and Atmospheric Administration’s Geophysical Fluid Dynamics Laboratory in Princeton.

Villarini G. and Vecchi GA. Twenty-first-century projections of North Atlantic tropical storms from CMIP5 models, Nature Climate Change
Published online 13 May 2012

Read a summary of the paper (Geophysical Fluid Dynamic Laboratory)


Novel drug candidates offer new route to controlling inflammation (J. Medicinal Chemistry)

An international team of researchers has designed and conducted initial tests on molecules that have the potential to treat diseases involving inflammation, such as asthma, rheumatoid arthritis, stroke and sepsis.

The team started by creating a three-dimensional map of a protein structure called the C3a receptor, which sits on the surface of human cells and plays a critical role in regulating a branch of the immune system called the complement system. They then used computational techniques to design short portions of protein molecules, known as peptides, that they predicted would interact with the receptor and either block or enhance aspects of its activity. Finally, experimentalists validated the theoretical predictions by synthesizing the peptides and testing them in animal and human cells.

The researchers – a collaboration of teams at four institutions on three continents – published their results May 10 in the Journal of Medicinal Chemistry.

The collaboration includes Christodoulos Floudas, the Stephen C. Macaleer ’63 Professor of Engineering and Applied Science in the Department of Chemical and Biological Engineering at Princeton University; Dimitrios Morikis, professor of bioengineering at the University of California, Riverside; Peter Monk of the Department of Infection and Immunity at the University of Sheffield Medical School, U.K.; and Trent Woodruff of the School of Biomedical Sciences at the University of Queensland, Australia.

Read the press release issued by Princeton University’s School of Engineering.

Read the abstract.

Study sheds light on how facial expressions evolved (Journal of Neuroscience)

A new study led by Asif Ghaz­an­far’s lab of Prince­ton Uni­ver­sity investigates the evolution of primate facial movements. They found that monkeys coordinate their facial muscles in different ways when communicating than when eating, and these distinct motor patterns implicate different neural mechanisms in the brainstem. These findings give insights into the evolutionary origins of human facial expressions.

Read the abstract: Facial Muscle Coordination in Monkeys during Rhythmic Facial Expressions and Ingestive Movements. Shepherd SA, Lanzilotto M, Ghazanfar AA. Journal of Neuroscience, 2 May 2012, 32(18): 6105-6116; doi: 10.1523/​JNEUROSCI.6136-11.2012