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.

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 September 20, 2014 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 September 20, 2014).

Share This



More Mind & Brain News

Saturday, September 20, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Could Grief Affect The Immune Systems Of Senior Citizens?

Could Grief Affect The Immune Systems Of Senior Citizens?

Newsy (Sep. 19, 2014) The study found elderly people are much more likely to become susceptible to infection than younger adults going though a similar situation. Video provided by Newsy
Powered by NewsLook.com
Food Addiction Might Be Caused By PTSD

Food Addiction Might Be Caused By PTSD

Newsy (Sep. 18, 2014) New research shows that women who suffer from PTSD are three times more likely to develop a food addiction. Video provided by Newsy
Powered by NewsLook.com
Corporal Punishment on Decline, Debate Renews

Corporal Punishment on Decline, Debate Renews

AP (Sep. 16, 2014) Corporal punishment in the United States is on the decline, but there is renewed debate over its use after Minnesota Vikings running back Adrian Peterson was charged with child abuse. (Sept. 16) Video provided by AP
Powered by NewsLook.com
FDA Eyes Skin Shocks Used at Mass. School

FDA Eyes Skin Shocks Used at Mass. School

AP (Sep. 15, 2014) The FDA is considering whether to ban devices used by the Judge Rotenberg Educational Center in Canton, Massachusetts, the only place in the country known to use electrical skin shocks as aversive conditioning for aggressive patients. (Sept. 15) Video provided by AP
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:
from the past week

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