Specific regions of the hippocampus connected to discrete steps of task mastery, study finds

October 1, 2012

(Medical Xpress)—In a study published in Nature Neuroscience, neurobiologists from the Friedrich Miescher Institute for Biomedical Research have been linking synapse formation in the hippocampus to distinct learning steps. They show how different regions of the hippocampus have specific and sequential functions in the mastery of a complex task.

The setup is natural. The mouse finds herself in the water and is looking for a dry place. But how does she solve this task? And what happens if she finds herself in the same situation again? Here is what the scientists observed: At the beginning, the mouse swims all around the little pool, randomly searching for the platform. After two days, there is a change in search approach: The mouse has learned where about the platform is and will start to search right away in the area of the platform. Finally, after another five days, the mouse knows exactly where the platform is and swims directly for it. What is astonishing is that every mouse behaves same way and all the mice learn to find the platform in about the same time, through the same trial and error search strategy stages.

Pico Caroni, senior group leader at the Friedrich Miescher Institute for , and his team not only described for the first time how mice learn to master such a complex task step by step, but they have also been able to show how one region of the brain, the hippocampus, is engaged in these learning processes. The hippocampus is the region of the brain that is the relay station for a lot of sensory information. In this function, the hippocampus is extremely important for learning and the consolidation of memory. The hippocampus can be divided into three areas termed ventral (vH), intermediate (iH) and dorsal hippocampus (dH). Even though the composition of the in each area is comparable, they differ in , connectivity, tuning and function.

Caroni and his team could now show that this difference has functional implications in learning. It has been known that during learning new synapses are formed in the hippocampus by so called mossy fibers. In their study published in the scientists show that each search strategy, each level of learning, is associated with a different region of the hippocampus. First, mossy fiber synapses are formed in vH. With the first change in search strategy, mossy fiber formation moves to iH. The mice now have a clear understanding of the relative position of the platform, e.g. distance from the pool wall. Finally, synapse formation moves to dH. By now the mouse has a clear map of the pool, the platform and her position in these surroundings. From now on the mouse will always know where the platform is and will directly head for it.

"We believe that many complex tasks are achieved through sub-tasks and that the three areas of the are involved in similar ways," comments Caroni. "Our experiments indicate further that this approach is innate, which indicates that similar processes may play as we learn to bike or become proficient in playing tennis."

Explore further: Scientists discover brain structures associated with learning

More information: Ruediger S, Spirig D, Donato F, Caroni P (2012) Goal-oriented searching mediated by ventral hippocampus early in trial-and-error learning. Nat Neurosci. 2012 Sep 23 [Epub ahead of print] www.nature.com/neuro/journal/v … nt/full/nn.3224.html

Related Stories

Scientists discover brain structures associated with learning

May 2, 2011
(Medical Xpress) -- Scientists at the Friedrich Miescher Institute for Biomedical Research (FMI, part of the Novartis Research Foundation) have discovered neuronal connections which are formed in the brain when learning occurs, ...

Learning left from right

December 21, 2011
(Medical Xpress) -- Pop psychology assertions about left-brain/right-brain differences are pretty much tosh. Our personalities are not dominated by a battle between the creative skills residing in one half of the brain competing ...

The hippocampus as a decision-maker

July 19, 2012
(Medical Xpress) -- Synapses are modified through learning. Up until now, scientists believed that a particular form of synaptic plasticity in the brain’s hippocampus was responsible for learning spatial relations. This ...

Learning requires rhythmical activity of neurons

September 26, 2012
The hippocampus represents an important brain structure for learning. Scientists at the Max Planck Institute of Psychiatry in Munich discovered how it filters electrical neuronal signals through an input and output control, ...

Recommended for you

Small but distinct differences among species mark evolution of human brain

November 23, 2017
The most dramatic divergence between humans and other primates can be found in the brain, the primary organ that gives our species its identity.

Team constructs whole-brain map of electrical connections key to forming memories

November 22, 2017
A team of neuroscientists at the University of Pennsylvania has constructed the first whole-brain map of electrical connectivity in the brain based on data from nearly 300 neurosurgical patients with electrodes implanted ...

To forget or to remember? Memory depends on subtle brain signals, scientists find

November 22, 2017
The fragrance of hot pumpkin pie can bring back pleasant memories of holidays past, while the scent of an antiseptic hospital room may cause a shudder. The power of odors to activate memories both pleasing and aversive exists ...

Pitch imperfect? How the brain decodes pitch may improve cochlear implants

November 22, 2017
Picture yourself with a friend in a crowded restaurant. The din of other diners, the clattering of dishes, the muffled notes of background music, the voice of your friend, not to mention your own – all compete for your ...

New research suggests high-intensity exercise boosts memory

November 22, 2017
The health advantages of high-intensity exercise are widely known but new research from McMaster University points to another major benefit: better memory.

Schizophrenia originates early in pregnancy, 'mini-brain' research suggests

November 20, 2017
Symptoms of schizophrenia usually appear in adolescence or young adulthood, but new research reveals that the brain disease likely begins very early in development, toward the end of the first trimester of pregnancy. The ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.