Why an alerted person counts for two

Jun 12, 2007

It was already known that people respond faster when prepared. However Dutch researcher Jan-Mathijs Schoffelen has now unravelled the mechanism in the brain behind this phenomenon. Transmitting and receiving neurons synchronise with each other so that the stimulus is transmitted more efficiently.

Neurones in the nervous system appear to function like cogs. If cogwheels can interlock well they rotate more supply. The parallel phenomenon in neurons is the rhythm of the transmitting and receiving neurones being synchronous (coherence). When the signal arrives, the receiving neuron is extra sensitive for the stimulus.

Schoffelen, a neuroscientist, demonstrated a greater level of coherence between the brain and spinal cord in prepared people. Consequently they had a faster response time than when they were not prepared for an action. The coherence occurred slightly earlier than the actual transmission of the stimulus, which indicates the presence of an active process.

Study subjects had to look at moving rings on a screen. They were asked to respond to changes in the speed of movement by moving their arms. By doing this Schoffelen manipulated the probability distribution for this change in speed. This increased or decreased over the course of time. In the 'practice session' the study subjects were trained on one of these probability distributions. The higher the probability of a change, the shorter the response time of the volunteers.

Coherence between the spinal cord and the brain was also found to reveal which areas of the brain are active during certain movements. This is a highly promising application, as the techniques used are not harmful to the body. Schoffelen made external measurements of the brain using magneto-encephalography (MEG) and external measurements of the electrical activity of the spinal muscles using electromyography (EMG). Schoffelen's research was funded by NWO Division for Earth and Life Sciences.

Source: NWO

Explore further: New compounds protect nervous system from the structural damage of MS

add to favorites email to friend print save as pdf

Related Stories

Canada looks east-west to ship oil after Keystone veto

2 hours ago

After US President Barack Obama vetoed a bill to expedite construction of the Keystone XL pipeline Tuesday, petroleum producers are expected to turn to Canadian routes to ship oil internationally, but hurdles ...

Internet access limited in developing world

3 hours ago

Most people in the developing world do not use the Internet, with access limited by high costs, poor availability and a lack of relevant content, a Facebook report said Tuesday.

Manhattan Project physicist Ralph Nobles dies at 94

3 hours ago

(AP)—Ralph Nobles, a nuclear physicist who worked on the Manhattan Project and later led efforts to save thousands of acres of San Francisco Bay wetlands from development, died following complications of pneumonia, according ...

In Japan, robot dogs are for life - and death

3 hours ago

Incense smoke wafts through the cold air of the centuries-old Buddhist temple as a priest chants a sutra, praying for the peaceful transition of the souls of the departed.

US sees little severe weather so far in 2015

3 hours ago

(AP)—While a big chunk of the nation deals with snow and ice, the U.S. is poised to end January and February with the fewest bouts of severe weather in decades.

Recommended for you

Mystery of the reverse-wired eyeball solved

Feb 27, 2015

From a practical standpoint, the wiring of the human eye - a product of our evolutionary baggage - doesn't make a lot of sense. In vertebrates, photoreceptors are located behind the neurons in the back of the eye - resulting ...

Neurons controlling appetite made from skin cells

Feb 27, 2015

Researchers have for the first time successfully converted adult human skin cells into neurons of the type that regulate appetite, providing a patient-specific model for studying the neurophysiology of weight ...

Quality control for adult stem cell treatment

Feb 27, 2015

A team of European researchers has devised a strategy to ensure that adult epidermal stem cells are safe before they are used as treatments for patients. The approach involves a clonal strategy where stem cells are collected ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.