"Long before it's in the papers"
January 27, 2015

RETURN TO THE WORLD SCIENCE HOME PAGE


Sense of direction may be innate

June 17, 2010
Courtesy of Norwegian University of Science and Technology
and World Science staff

Are we born with a sense of di­rec­tion, or is it learn­ed? New re­search sug­gests the brain comes hard-wired with work­ing naviga­t­ional cells, or neu­rons. 

While these neu­rons – head di­rec­tion cells, place cells and grid cells – ma­ture over time, they func­tion in ro­dents as soon as they make their first ex­plor­a­to­ry steps out­side the nest, a study sug­gests.

New re­search with ba­by rats sug­gests the brain comes hard wired with a sense of di­rec­tion. (Cour­te­sy Nor­we­gian Uni­vers­ity of Sci­ence and Tech­nol­o­gy)


Re­search­ers Ro­sa­mund Langs­ton of the Nor­we­gian Uni­vers­ity of Sci­ence and Tech­nol­o­gy and col­leagues wanted to know how the brain mapped place and space when an an­i­mal nav­i­gates for the first time ev­er. 

The group im­planted min­ia­ture sen­sors in rat pups be­fore their eyes had opened and be­fore they were mo­bile. That en­a­bled the re­search­ers to rec­ord brain cell ac­ti­vity when the pups left the nest for the first time.

The re­search­ers were not only able to see that the rats had work­ing naviga­t­ional neu­rons from the be­gin­ning, but they were al­so able to see the or­der in which the cells ma­tured. 

The first to ma­ture were head di­rec­tion cells, the group found. These neu­rons tell the an­i­mal which di­rec­tion it is head­ing, and are thought to ena­ble an in­ter­nal inertia-based naviga­t­ion sys­tem, like a com­pass. “These cells were al­most adult-like right from the be­gin­ning,” Langs­ton said.

Next to ma­ture were place cells, found in a brain struc­ture called the hip­po­cam­pus. These cells rep­re­sent a spe­cif­ic place in the en­vi­ron­ment, and in ad­di­tion pro­vide con­tex­tu­al in­forma­t­ion — per­haps even a mem­o­ry — that might be as­so­ci­at­ed with the place. Last to ma­ture were grid cells, which pro­vide the brain with a ge­o­met­ric co­or­di­nate sys­tem that ena­bles the an­i­mal to fig­ure out where it is in space and how far it has trav­elled, said Langs­ton and col­leagues. Grid cells es­sen­tially an­chor the oth­er cell types to the out­side world so that the an­i­mal can re­liably re­pro­duce the men­tal map that was made last time it was there.

Ba­by rats open their eyes and beg­in ex­plor­ing by about 15 days of age. At this point, re­search­ers found di­rec­tion cells were fully de­vel­oped, and the rudi­ments of the oth­er two cell types in place. By the time they were 30 days old, or on the thresh­old of rat ad­o­les­cence, vir­tu­ally all of the dif­fer­ent naviga­t­ional cell types had ma­tured, ac­cord­ing to the sci­en­tists.

Langs­ton said the find­ings are a par­tial an­swer to the age-old ques­tion of wheth­er or not you are born with the in­nate abil­ity to find your way around. “It really seems that this is hard-wired,” she said, “You do have a bas­ic founda­t­ion that is there as soon as you can ex­plore – there are strong build­ing blocks for a sys­tem that you can use to nav­i­gate.” Langs­ton said ex­pe­ri­ence could al­so play a role, which makes this top­ic an im­por­tant theme for fur­ther re­search.

The re­search­ers found no dif­fer­ence in naviga­t­ional skills be­tween male and female rat pups, sug­gest­ing both sexes have the same build­ing blocks with which to con­struct rep­re­senta­t­ions of space. Per­haps the age-old ques­tion of wheth­er males or females have a bet­ter sense of di­rec­tion could be a case of how we choose to build our map, rath­er than the ma­te­ri­als we start with, Langs­ton said.


* * *

Send us a comment on this story, or send it to a friend









 

Sign up for
e-newsletter
   
 
subscribe
 
cancel

On Home Page         

LATEST

  • St­ar found to have lit­tle plan­ets over twice as old as our own

  • “Kind­ness curricu­lum” may bo­ost suc­cess in pre­schoolers

EXCLUSIVES

  • Smart­er mice with a “hum­anized” gene?

  • Was black­mail essen­tial for marr­iage to evolve?

  • Plu­to has even cold­er “twin” of sim­ilar size, studies find

  • Could simple an­ger have taught people to coop­erate?

MORE NEWS

  • F­rog said to de­scribe its home through song

  • Even r­ats will lend a help­ing paw: study

  • D­rug may undo aging-assoc­iated brain changes in ani­mals

Are we born with a sense of direction, or is it learned? New research suggests that the brain comes hard-wired with working navigational cells, or neurons. While these neurons – head direction cells, place cells and grid cells – mature over time, they appear to function in rodents as soon as they make their first exploratory steps outside the nest, a study suggests. Researchers Rosamund Langston of the Norwegian University of Science and Technology and colleagues wanted to know how the brain mapped place and space when an animal navigates for the first time ever. The group implanted miniature sensors in rat pups before their eyes had opened and before they were mobile. That enabled the researchers to record brain cell activity when the rat pups left the nest for the first time to explore a new environment. The researchers were not only able to see that the rats had working navigational neurons from the beginning, but they were also able to see the order in which the cells matured. The first to mature were head direction cells, the group found. These neurons tell the animal which direction it is heading, and are thought to enable an internal inertia-based navigation system, like a compass. “These cells were almost adult-like right from the beginning,” Langston said. Next to mature were place cells, found in a brain structure called the hippocampus. These cells represent a specific place in the environment, and in addition provide contextual information — perhaps even a memory — that might be associated with the place. Last to mature were grid cells, which provide the brain with a geometric coordinate system that enables the animal to figure out where it is in space and how far it has travelled, said Langston and colleagues. Grid cells essentially anchor the other cell types to the outside world so that the animal can reliably reproduce the mental map that was made last time it was there. Baby rats open their eyes and begin exploring by about 15 days of age. At this point, researchers found direction cells were fully developed, and the rudiments of the other two cell types in place. By the time they were 30 days old, or on the threshold of rat adolescence, virtually all of the different navigational cell types had matured, according to the scientists. Langston said the findings are a partial answer to the age-old question of whether or not you are born with the innate ability to find your way around. “It really seems that this is hard-wired,” she said, “You do have a basic foundation that is there as soon as you can explore – there are strong building blocks for a system that you can use to navigate. “ Langston said experience could also play a role, which makes this topic an important theme for further research. The researchers found no difference in navigational skills between male and female rat pups, suggesting both sexes have the same building blocks with which to construct representations of space. Perhaps the age-old question of whether males or females have a better sense of direction could be a case of how we choose to build our map, rather than the materials we start with, Langston said.