In order to guide us accurately through space, the brain needs a “sense” of the speed of our movement. But how do such stimuli actually reach the brain? Researchers at the German Center for Neurodegenerative Diseases (DZNE) have now identified a signal pathway in mice that feeds speed information directly into the brain’s navigation system. Scientists led by Stefan Remy report on this in the journal “Nature Neuroscience”. Similar neural pathways exist in humans. They are known to be damaged by Alzheimer’s disease – a possible explanation why spatial orientation is frequently impaired in this form of dementia.
In this study, the researchers stimulated specific areas in the brains of mice and recorded the evoked brain activity. “In previous studies, we found specific cells in the medial septum that fire at higher rates when the mouse moves faster. They function as ‘speedometer cells’. Possibly, they receive their input from deeper brain areas that are involved in motion control”, explains Professor Remy.
DZNE researchers have identified a neural pathway that feeds speed information directly into the brain’s navigation system. Image: DZNE/Daniel Justus; OpenStreetMap
Neuronal data bus
These neurons are connected to other brain regions via long-range projections. This includes an area called the “entorhinal cortex” which is considered to be the brain’s navigation center. “The computations needed to navigate in space are ultimately made in this area of the brain,” says Remy.
“We have now been able to show that the rate at which the speedometer cells fire influences neuronal activity in the entorhinal cortex. When the firing rate increases, activity in the entorhinal cortex increases too. The speedometer cells act like a data bus, an interface that relays speed information directly to the brain's navigation center.”
Cause of spatial orientation disorders?
Humans have similar neural pathways connecting the medial septum and entorhinal cortex. Their function has not yet been investigated in detail; however, in the brains of Alzheimer’s patients these connections are known to degenerate early in the progress of the disease.
“The symptoms of Alzheimer’s disease include spatial memory impairments. In such cases, it might happen that an affected person cannot find the way home,” says Remy. “Our results now provide a possible explanation for these symptoms: Information about the ongoing speed of movement is withheld and does not reach the brain’s navigation center.”
“Glutamatergic synaptic integration of locomotion speed via septoentorhinal projections”, Daniel Justus, Dennis Dalügge, Stefanie Bothe, Falko Fuhrmann, Christian Hannes, Hiroshi Kaneko, Detlef Friedrichs, Liudmila Sosulina, Inna Schwarz, David Anthony Elliott, Susanne Schoch, Frank Bradke, Martin Karl Schwarz, Stefan Remy, Nature Neuroscience, DOI: http://dx.doi.org/10.1038/nn.4447
Dr. Marcus Neitzert | idw - Informationsdienst Wissenschaft
Enabling technology in cell-based therapies: Scale-up, scale-out or program in-place
23.07.2018 | SLAS (Society for Laboratory Automation and Screening)
FAU researchers identify Parkinson's disease as a possible autoimmune disease
23.07.2018 | Friedrich-Alexander-Universität Erlangen-Nürnberg
A new manufacturing technique uses a process similar to newspaper printing to form smoother and more flexible metals for making ultrafast electronic devices.
The low-cost process, developed by Purdue University researchers, combines tools already used in industry for manufacturing metals on a large scale, but uses...
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
23.07.2018 | Materials Sciences
23.07.2018 | Information Technology
23.07.2018 | Health and Medicine