“We have developed a procedure which can repair severed nerves within minutes so that the behaviour they control can be partially restored within days and often largely restored within two to four weeks,” said Professor George Bittner, University of Texas. “If further developed in clinical trials this approach would be a great advance on current procedures that usually imperfectly restore lost function within months at best.”

 The team studied the mechanisms all animal cells use to repair damage to their membranes and focused on invertebrates, which have a superior ability to regenerate nerve axons compared to mammals. An axon is a long extension arising from a nerve cell body that communicates with other nerve cells or with muscles.

Research success arises from Bittner’s discovery that nerve axons of invertebrates which have been severed from their cell body do not degenerate within days, as happens with mammals, but can survive for months, or even years.

The severed proximal nerve axon in invertebrates can also reconnect with its surviving distal nerve axon to produce much quicker and much better restoration of behaviour than occurs in mammals.

“Severed invertebrate nerve axons can reconnect proximal and distal ends of severed nerve axons within seven days, allowing a rate of behavioural recovery that is far superior to mammals,” says (left) Bittner. “In mammals the severed distal axonal stump degenerates within three days and it can take nerve growths from proximal axonal stumps months or years to regenerate and restore use of muscles or sensory areas, often with less accuracy and with much less function being restored.”

The team applied this process to rats in two research papers Journal of Neuroscience Research and were able to repair severed sciatic nerves in the upper thigh, showing the rats were able to use their limb within a week and had much function restored within 2 to 4 weeks, in some cases to almost full function.

“We used rats as an experimental model to demonstrate how severed nerve axons can be repaired. Without our procedure return of nearly full function rarely comes close to happening,” said Bittner. “The sciatic nerve controls all muscle movement of the leg of all mammals and this new approach to repairing nerve axons could almost-certainly be just as successful in humans.”

MD’s and other scientist-collaborators at Harvard Medical School and Vanderbilt Medical School and Hospitals are conducting studies to obtain approval to begin clinical trials.

“We believe this procedure could produce a transformational change in the way nerve injuries are repaired,” concluded Bittner. "The cellular mechanism use is similar by that used by many invertebrates to repair damage to nerve axons."

SYNCHRONISED STRONG OSCILLATIONS IN THE THETA BAND  
Memorising information for a short term is a seemingly simple and everyday task. Short-term memory remember a new telephone if there is nothing to write at hand, or to can recall and match dress shape from the window to the unit in store. But despite it simplicity, short-term memory is a complex cognitive act, that needs participation by multiple brain reasons. But whether and how these regions cooperate during memory has been unclear.

Max Planck Institute for Biological Cybernetics researchers in Tübingen, Germany have now come closer to answers discovering that oscillations between brain regions are crucial in visually remembering things over a short period of time. 

The frontal brain is involved in short-term memory. Processing of visual information occurs primarily at the back of the brain. To successfully remember visual information over a short period of time, these regions need to coordinate and integrate information.

Scientists from the Max Planck Institute of Biological Cybernetics in the department of (right) Nikos Logothetis recorded electrical activity both in a visual area and in the frontal part of the brain in monkeys.  They show the animals identical or different images within short intervals, recording their brain activity. The animals then had to indicate whether the second image was the same as the first one.

In each of the two brain regions, brain activity showed strong oscillations in a certain set of frequencies, the theta-band. These oscillations did not occur independently of each other, but synchronised their activity temporarily.

“It is as if you have two revolving doors in each of the two areas. During working memory, they get in sync, thereby allowing information to pass through them much more efficiently than if they were out of sync,” explains Stefanie Liebe, the study's first author conducted in the team of Gregor Rainer, in cooperation with Gregor Hörzer from the Technical University Graz.

The more synchronised the activity, the better could the animals remember the initial image and they were able to establish a direct relationship between what they observed in the brain and the animal performance.

The study highlights how synchronized brain oscillations are important for the communication and interaction of different brain regions. Almost all multi-faceted cognitive acts, such as visual recognition, are a complex interplay of specialised and distributed neural networks.

How relationships between such distributed sites are established and how they contribute to represent and communicate information about external and internal events attain a coherent percept or memory is still poorly understood.