Featured Research

from universities, journals, and other organizations

Neurons For Numerosity: Parietal Neurons 'Sum Up' Individual Items In A Group

Date:
July 25, 2007
Source:
PLoS Biology
Summary:
As any child knows, to answer the question "how many," one must start by adding up individual objects in a group. This cognitive ability is shared by animals as diverse as humans and birds. Surprisingly, the exact brain mechanisms responsible for this process remained unknown until now.

Neurons in the lateral intraparietal area of the monkey brain have been shown to integrate information about space and time. A new study asks whether they also "add up" numerical quantity.
Credit: Article authors and PLoS Biology

As any child knows, to answer the question "how many," one must start by adding up individual objects in a group. This cognitive ability is shared by animals as diverse as humans and birds.

Related Articles


Surprisingly, the exact brain mechanisms responsible for this process remained unknown until now. In PLoS Biology, Jamie Roitman, Elizabeth Brannon, and Michael Platt from the University of Illinois at Chicago now report novel evidence for the existence of "accumulator neurons," which respond to increasing numbers of items in a display with progressively increasing activity, in the parietal cortex of monkeys.

The authors focused on the parietal cortex based on evidence that damage to this brain region disrupts basic mathematical skills, and is activated during functional imaging studies when people perform basic computations. To understand how parietal cortex contributes to numerical behavior, the authors studied the activity of neurons in the lateral intraparietal area in monkeys while they looked at arrays of dots on a computer screen.

Parietal neurons responded with progressively increasing activity as the total number of elements in the display was varied across a wide range of values (2-32). These neurons resemble "accumulator neurons" that have been suggested to serve the first stage in counting.

This information could be used by other neurons that respond best for a particular cardinal number, such as "4," as have been reported in prior studies. These findings support computer models that separate the processes of summing and numerical identification, and may also explain the fact that parietal cortex damage causes both numerical and spatial confusion.

Neurons in the lateral intraparietal area in monkeys respond in a graded fashion to the number of items in a visual array during a delayed saccade task, suggesting that the neurons "sum up" individual elements to represent accumulated magnitude.

Citation: Roitman JD, Brannon EM, Platt ML (2007) Monotonic coding of numerosity in macaque lateral intraparietal area. PLoS Biol 5(8): e208. doi:10.1371/journal.pbio. 0050208.


Story Source:

The above story is based on materials provided by PLoS Biology. Note: Materials may be edited for content and length.


Cite This Page:

PLoS Biology. "Neurons For Numerosity: Parietal Neurons 'Sum Up' Individual Items In A Group." ScienceDaily. ScienceDaily, 25 July 2007. <www.sciencedaily.com/releases/2007/07/070724114048.htm>.
PLoS Biology. (2007, July 25). Neurons For Numerosity: Parietal Neurons 'Sum Up' Individual Items In A Group. ScienceDaily. Retrieved March 2, 2015 from www.sciencedaily.com/releases/2007/07/070724114048.htm
PLoS Biology. "Neurons For Numerosity: Parietal Neurons 'Sum Up' Individual Items In A Group." ScienceDaily. www.sciencedaily.com/releases/2007/07/070724114048.htm (accessed March 2, 2015).

Share This


More From ScienceDaily



More Mind & Brain News

Monday, March 2, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

How Facebook Use Can Lead To Depression

How Facebook Use Can Lead To Depression

Newsy (Mar. 1, 2015) Margaret Duffy of the University of Missouri talks about her study on the social network and the envy and depression that Facebook use can cause. Video provided by Newsy
Powered by NewsLook.com
The Best Foods to Battle Stress

The Best Foods to Battle Stress

Buzz60 (Feb. 26, 2015) If you&apos;re dealing with anxiety, there are a few foods that can help. Krystin Goodwin (@krystingoodwin) has the best foods to tame stress. Video provided by Buzz60
Powered by NewsLook.com
Sleeping Too Much Or Too Little Might Increase Stroke Risk

Sleeping Too Much Or Too Little Might Increase Stroke Risk

Newsy (Feb. 26, 2015) People who sleep more than eight hours per night are 45 percent more likely to have a stroke, according to a University of Cambridge study. Video provided by Newsy
Powered by NewsLook.com
Mayor Says District of Columbia to Go Ahead With Pot Legalization

Mayor Says District of Columbia to Go Ahead With Pot Legalization

Reuters - News Video Online (Feb. 25, 2015) Washington&apos;s mayor says the District of Columbia will move forward with marijuana legalization, despite pushback from Congress. Rough Cut (no reporter narration). Video provided by Reuters
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins