Hand representations in the brain are increased at the age
RUB researchers report in "Cerebral Cortex"
At the age many things are not as good as at a young age. Besides hearing and eyesight also the power of touch decreases. Ordinary as buttoning a shirt then develop into a challenge. The neuroscientific Bochum group led by Prof. Dr. Martin Tegenthoff (Neurology Bergmannsheil) and PD Dr. Hubert Dinse (Institute for Neuro computer science) have now found that the representation of the hand in the brain in the elderly is significantly greater than in younger. There are age-related changes so other mechanisms based as learning where greater representation with better performance accompanied. The researchers report in the prestigious journal "Cerebral Cortex".
How big is the image of the hand in the brain
The functional organization of the human brain follows special ordering principles. For example, tactile sensations perceived via neighboring areas of skin are also processed in neighboring representations in the corresponding part of our brain. This creates a complete representation of the human body in the human brain, the "homunculus". In order to be able to measure the spatial extent of these hand representations, the scientists stimulated the index fingers and little fingers of young subjects between the ages of 19 and 35 and older subjects between the ages of 60 and 85 during an EEG measurement. The corresponding finger representations in the somatosensory part of the brain are activated by the stimulation and can be described by localizing the activation sources in spatial coordinates. The distances between the activation sources calculated for the index finger and the little finger serve to describe the size of the hand representation.
Surprise: Greater representation in older people
The sense of touch of older people is worse than that of young people in both the right and left hand area. In young subjects, a learning-related improvement in the sense of touch is typically associated with enlarged representational areas. Therefore, the Bochum researchers had expected to find smaller representations of the hand/finger areas in the brain of their elderly test subjects. However, the opposite was the case: despite poorer performance, the hand representations of the older test subjects were significantly larger than those of the young test subjects. Older people thus activate larger parts of their brain for a sensory task, even if it is performed less well. This suggests that the observed cortical changes in the brain of the elderly are subject to different mechanisms than those associated with learning-related changes.
The aim of further research is now to develop training and therapy methods for older people to maintain their everyday skills for a longer period of time through a better understanding of these initially unexpected age-related brain changes.
Title Shot
Tobias Kalisch, Patrick Ragert, Peter Schwenkreis, Hubert R. Dinse, Martin Tegenthoff. Impaired tactile acuity in old age is accompanied by enlarged hand representations in somatosensory cortex. In: Cerebral Cortex, 2008 Nov 13. [Epub ahead of print]
Source: Bochum [RUB]
