Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Neural architecture

25.02.2008
The neurons in the primary visual cortex processing high- and low-frequency images are distinct

Neuroscientists from the RIKEN Brain Science Institute, Wako, and New York University have used functional magnetic resonance imaging (fMRI) to study the organization of neurons in the primary visual cortex (V1) of humans and establish that the temporal frequency of a stimulus activates specific V1 neurons.

The V1 is an area at the back of the brain where the first stage of visual processing takes place. Although this is one of the most heavily studied parts of the visual cortex, little is known about how its neurons are arranged. In general, neurons with similar selectivity for visual stimuli cluster together. For example, V1 neurons that process stimuli from each eye are grouped into pillars, called ocular dominance columns.

V1 neurons are highly sensitive to the contrast, orientation, and spatio-temporal frequency of a visual stimulus. Temporal frequency is an important determinant of how moving images are processed by the brain and is a measure of how often an image appears in the visual field. This attribute is also of particular interest to RIKEN researcher Pei Sun and his team, headed by Keiji Tanaka and Kang Cheng, who have determined that images appearing less frequently over time are handled by neurons that arrange themselves differently to those that are activated by more frequently appearing images.

The fMRI technique allows the function and anatomical structure of the brain to be studied live and works by measuring the level of oxygen in the blood immediately after a neuron has been active, giving a pattern of which neurons have been triggered by a stimulus.

The team has shown that separate domains in human V1 respond preferentially to low- and high-temporal frequencies. The former appear to be continuous, whereas the latter seem to be more like isolated islands with no particular orientation (Fig. 1).

This study provides direct physiological evidence that different temporal frequencies are preferentially processed by spatially segregated streams in human V1. The work recently published in Nature Neuroscience (1) is the first to show neuronal organization specific to temporal frequency in primate V1.

Evidence of these separate neural regions will assist further study into human perception of moving images and help to develop a map of the neural architecture of the brain. Pei plans to develop the fMRI technique as “it could link animal and human behavioral studies, giving a better picture of how information is processed by the brain,” he says.

Reference

1. Sun, P., Ueno, K., Waggoner, R.A., Gardner, J.L., Tanaka, K. & Cheng, K. A temporal frequency-dependent functional architecture in human V1 revealed by high-resolution fMRI. Nature Neuroscience 10, 1404–1406 (2007).

Saeko Okada | ResearchSEA
Further information:
http://www.rikenresearch.riken.jp/research/390/

More articles from Studies and Analyses:

nachricht New study from the University of Halle: How climate change alters plant growth
12.01.2018 | Martin-Luther-Universität Halle-Wittenberg

nachricht Disarray in the brain
18.12.2017 | Universität zu Lübeck

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Artificial agent designs quantum experiments

On the way to an intelligent laboratory, physicists from Innsbruck and Vienna present an artificial agent that autonomously designs quantum experiments. In initial experiments, the system has independently (re)discovered experimental techniques that are nowadays standard in modern quantum optical laboratories. This shows how machines could play a more creative role in research in the future.

We carry smartphones in our pockets, the streets are dotted with semi-autonomous cars, but in the research laboratory experiments are still being designed by...

Im Focus: Scientists decipher key principle behind reaction of metalloenzymes

So-called pre-distorted states accelerate photochemical reactions too

What enables electrons to be transferred swiftly, for example during photosynthesis? An interdisciplinary team of researchers has worked out the details of how...

Im Focus: The first precise measurement of a single molecule's effective charge

For the first time, scientists have precisely measured the effective electrical charge of a single molecule in solution. This fundamental insight of an SNSF Professor could also pave the way for future medical diagnostics.

Electrical charge is one of the key properties that allows molecules to interact. Life itself depends on this phenomenon: many biological processes involve...

Im Focus: Paradigm shift in Paris: Encouraging an holistic view of laser machining

At the JEC World Composite Show in Paris in March 2018, the Fraunhofer Institute for Laser Technology ILT will be focusing on the latest trends and innovations in laser machining of composites. Among other things, researchers at the booth shared with the Aachen Center for Integrative Lightweight Production (AZL) will demonstrate how lasers can be used for joining, structuring, cutting and drilling composite materials.

No other industry has attracted as much public attention to composite materials as the automotive industry, which along with the aerospace industry is a driver...

Im Focus: Room-temperature multiferroic thin films and their properties

Scientists at Tokyo Institute of Technology (Tokyo Tech) and Tohoku University have developed high-quality GFO epitaxial films and systematically investigated their ferroelectric and ferromagnetic properties. They also demonstrated the room-temperature magnetocapacitance effects of these GFO thin films.

Multiferroic materials show magnetically driven ferroelectricity. They are attracting increasing attention because of their fascinating properties such as...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

10th International Symposium: “Advanced Battery Power – Kraftwerk Batterie” Münster, 10-11 April 2018

08.01.2018 | Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

 
Latest News

Let the good tubes roll

19.01.2018 | Materials Sciences

How cancer metastasis happens: Researchers reveal a key mechanism

19.01.2018 | Health and Medicine

Meteoritic stardust unlocks timing of supernova dust formation

19.01.2018 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>