Featured Research

from universities, journals, and other organizations

Spatial memory: Mapping blank spots in the cheeseboard maze

Date:
March 22, 2013
Source:
Institute of Science and Technology Austria
Summary:
During learning, novel information is transformed into memory through the processing and encoding of information in neural circuits. Scientists have now uncovered a novel role for inhibitory interneurons in the rat hippocampus during the formation of spatial memory.

Image of rat on a cheeseboard maze. Neuronal traces show action potentials for some recorded cells at the reward locations. LED traces taken by long exposure show the movement of the animal across the maze.
Credit: Image courtesy of Institute of Science and Technology Austria

IST Austria Professor Jozsef Csicsvari together with collaborators has succeeded in uncovering processes in which the formation of spatial memory is manifested in a map representation.

Related Articles


During learning, novel information is transformed into memory through the processing and encoding of information in neural circuits. In a recent publication in Neuron, IST Austria Professor Jozsef Csicsvari, together with his collaborator David Dupret at the University of Oxford, and Joseph O'Neill, postdoc in Csicsvari's group, uncovered a novel role for inhibitory interneurons in the rat hippocampus during the formation of spatial memory.

During spatial learning, space is represented in the hippocampus through plastic changes in the connections between neurons. Jozsef Csicsvari and his collaborators investigate spatial learning in rats using the cheeseboard maze apparatus. This apparatus contains many holes, some of which are selected to hide food in order to test spatial memory. During learning trials, animals learn where the rewards are located, and after a period sleep, the researchers test whether the animal can recall these reward locations. In previous work, they and others have shown that memory of space is encoded in the hippocampus through changes in the firing of excitatory pyramidal cells, the so-called "place cells."

A place cell fires when the animal arrives at a particular location. Normally, place cells always fire at the same place in an environment; however, during spatial learning the place of their firing can change to encode where the reward is found, forming memory maps.

In their new publication, the researchers investigated the timescale of map formation, showing that during spatial learning, pyramidal neuron maps representing previous and new reward locations "flicker," with both firing patterns occurring. At first, old maps and new maps fluctuate, as the animal is unsure whether the location change is transient or long-lasting. At a later stage, the new map and so the relevant new information dominates.

The scientists also investigated the contribution of inhibitory interneuron circuits to learning. They show that these interneurons, which are extensively interconnected with pyramidal cells, change their firing rates during map formation and flickering: some interneurons fire more often when the new pyramidal map fires, while others fire less often with the new map. These changes in interneuron firing were only observed during learning, not during sleep or recall. The scientists also show that the changes in firing rate are due to map-specific changes in the connections between pyramidal cells and interneurons. When a pyramidal cell is part of a new map, the strengthening of a connection with an interneuron causes an increase in the firing of this interneuron. Conversely, when a pyramidal cell is not part of a new map, the weakening of the connection with the interneuron causes a decrease in interneuron firing rate. Both, the increase and the decrease in firing rate can be beneficial for learning, allowing the regulation of plasticity between pyramidal cells and controlling the timing in their firing.

The new research therefore shows that not only excitatory neurons modify their behaviour and exhibit plastic connection changes during learning, but also the inhibitory interneuron circuits. The researchers suggest that inhibitory interneurons could be involved in map selection -- helping one map dominate and take over during learning, so that the relevant information is encoded.


Story Source:

The above story is based on materials provided by Institute of Science and Technology Austria. Note: Materials may be edited for content and length.


Journal Reference:

  1. David Dupret, Joseph O’Neill, Jozsef Csicsvari. Dynamic Reconfiguration of Hippocampal Interneuron Circuits during Spatial Learning. Neuron, 2013; DOI: 10.1016/j.neuron.2013.01.033

Cite This Page:

Institute of Science and Technology Austria. "Spatial memory: Mapping blank spots in the cheeseboard maze." ScienceDaily. ScienceDaily, 22 March 2013. <www.sciencedaily.com/releases/2013/03/130322104258.htm>.
Institute of Science and Technology Austria. (2013, March 22). Spatial memory: Mapping blank spots in the cheeseboard maze. ScienceDaily. Retrieved December 20, 2014 from www.sciencedaily.com/releases/2013/03/130322104258.htm
Institute of Science and Technology Austria. "Spatial memory: Mapping blank spots in the cheeseboard maze." ScienceDaily. www.sciencedaily.com/releases/2013/03/130322104258.htm (accessed December 20, 2014).

Share This


More From ScienceDaily



More Mind & Brain News

Saturday, December 20, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Researchers Test Colombian Village With High Alzheimer's Rates

Researchers Test Colombian Village With High Alzheimer's Rates

AFP (Dec. 19, 2014) In Yarumal, a village in N. Colombia, Alzheimer's has ravaged a disproportionately large number of families. A genetic "curse" that may pave the way for research on how to treat the disease that claims a new victim every four seconds. Duration: 02:42 Video provided by AFP
Powered by NewsLook.com
Double-Amputee Becomes First To Move Two Prosthetic Arms With His Mind

Double-Amputee Becomes First To Move Two Prosthetic Arms With His Mind

Buzz60 (Dec. 19, 2014) A double-amputee makes history by becoming the first person to wear and operate two prosthetic arms using only his mind. Jen Markham has the story. Video provided by Buzz60
Powered by NewsLook.com
Prenatal Exposure To Pollution Might Increase Autism Risk

Prenatal Exposure To Pollution Might Increase Autism Risk

Newsy (Dec. 18, 2014) Harvard researchers found children whose mothers were exposed to high pollution levels in the third trimester were twice as likely to develop autism. Video provided by Newsy
Powered by NewsLook.com
Yoga Could Be As Beneficial For The Heart As Walking, Biking

Yoga Could Be As Beneficial For The Heart As Walking, Biking

Newsy (Dec. 17, 2014) Yoga can help your weight, blood pressure, cholesterol and heart just as much as biking and walking does, a new study suggests. Video provided by Newsy
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