Neuronal research: The brain needs to feel the beat

July 19, 2000

How do the eyes "speak" with the brain to convey visual information? And how does the brain reconstruct tactile sensations formed at ones fingertips?

Scientists have long known that sensory information such as touch, vision, and hearing is converted into electrochemical impulses and channeled by neuronal pathways to respective sensory areas in the brain. The data, organized in the same spatial pattern as that obtained by the sensory organs, is then processed to divulge its encrypted messages.

However, a recent study by Dr. Ehud Ahissar of the Weizmann Institute of Science suggests that in processing tactile information, the brain requires more than spatial patterning. Put simply -- it needs to feel the beat.

Due to appear in the July 20 issue of Nature, the study shows that tactile information is encoded by both spatial and temporal data. In a series of experiments in animal models, Ahissar and colleagues at the Neurobiology Department found that soon after sensory input is translated into electrical impulses, these divide into parallel pathways. The first is probably responsible for spatial data, while the second processes temporal data. "The brain compares the timing of cells activated by external stimuli to the internal timing of other brain cells, which operate much like a metronome," says Ahissar.

Previous attempts to uncover the functional significance of the temporal pathway were thwarted by technical difficulties. Ahissar's team overcame this obstacle by designing an improved experimental strategy, which included using stimuli similar to those found in the natural environment.

The findings also suggest a where and what scheme, encoded by the frequency of incoming stimuli. The temporal pathway primarily processes low frequency stimuli, sufficient for determining an object's location. In contrast, the spatial pathway focuses on high-frequency stimuli, making it better suited for representing an object's features. "Most textures in nature are highly detailed," explains Ahissar. "Imagine running your finger across a fabric. The more complex the texture, the more 'bumps' of tactile information encountered, meaning a higher frequency of incoming data to be processed."

The current study may contribute to improving tactile aids for the blind. According to Ahissar, these aids were originally designed to accommodate the known physiology of the fingertip without regard to brain processing. For instance, Braille letters are too long, so users often have to scan the information twice to retrieve all the data and then "stitch" it together. Since the new evidence suggests that efficient tactile processing must be done in continuum, this may explain the relatively low speed of most Braille readers. As with much in life, it's all about timing.
-end-
This research is funded by the Abramson Family Foundation, North Bethesda, MD, the Nella and Leon Benoziyo Center for Neurosciences and the Murray H. and Meyer Grodetsky Center for Higher Brain Functions.




American Committee for the Weizmann Institute of Science

Related Aids Articles from Brightsurf:

Developing a new vaccination strategy against AIDS
Infection researchers from the German Primate Center (DPZ) -- Leibniz Institute for Primate Research have in cooperation with international colleagues tested a new vaccination strategy against the HIV-related simian immunodeficiency virus (SIV) in rhesus monkeys.

HIV-AIDS: Following your gut
Researchers find a way to reduce replication of the AIDS virus in the gastrointestinal tract.

A path toward ending AIDS in the US by 2025
Using prevention surveillance data to model rates of HIV incidence, prevalence and mortality, investigators at Brigham and Women's Hospital and Johns Hopkins Bloomberg School of Public Health set targets, specifically a decrease in new infections to 21,000 by 2020 and to 12,000 by 2025, that would mark a transition toward ending the HIV/AIDS epidemic.

What does it take for an AIDS virus to infect a person?
Researchers examined the characteristics of HIV-1 strains that were successful in traversing the genital mucosa that forms a boundary to entry by viruses and bacteria.

How AIDS conquered North America
A new technique that allowed researchers to analyze genetic material from serum samples of HIV patients taken before AIDS was known provides a glimpse of unprecedented detail into the beginnings of the AIDS epidemic in North America.

New research could help build better hearing aids
Scientists at Binghamton University, State University of New York want to improve sensor technology critical to billions of devices made every year.

NY State Department of Health AIDS Institute funds HIV/AIDS prevention in high-risk youth
NewYork-Presbyterian's Comprehensive Health Program and Project STAY, an initiative of the Harlem Heath Promotion Center (HHPC) at Columbia University's Mailman School of Public Health has received two grants totaling more than $3.75 million from the New York State Department of Health AIDS Institute for their continued efforts to prevent HIV/AIDS in at-risk youth.

A new way to nip AIDS in the bud
When new HIV particles bud from an infected cell, the enzyme protease activates to help the viruses infect more cells.

AIDS research prize for Warwick academic
A researcher at the University of Warwick has received international recognition for his contribution to AIDS research.

Insects inspire next generation of hearing aids
An insect-inspired microphone that can tackle the problem of locating sounds and eliminate background noise is set to revolutionize modern-day hearing aid systems.

Read More: Aids News and Aids Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.