Posts Tagged ‘hippocampus’

Hippocampus Takes Control of Learning

Friday, February 18th, 2011

Each week my first grade son brings home a new set of “spelling words”. It’s often a struggle to get him to focus on word study when a Clone Wars Lego project beckons. But this week my wife, faced with a particularly thorny set of new words, hit on the idea of getting Zane to integrate them into a star wars story. Fantastic!  Twenty minutes later we had a new scene synopsis for George Lucas complete with snakes and licks and dukes, and the next day Zane scored 100% on his spelling review.

Logical, inspired, and now supported by a new research study, the idea that we learn better when we have some active engagement in the learning process makes ample sense but seems to be sadly lacking from many pedagogical strategies.

Neal Cohen, University of Illinois psychology and Beckman Institute professor led the study with postdoctoral researcher Joel Voss. “Having active control over a learning situation is very powerful and we’re beginning to understand why,” commented Cohen. “Whole swaths of the brain not only turn on, but also get functionally connected when you’re actively exploring the world.”

Brain Training Online

Focused on the hippocampus and several other integrated brain regions, Voss asked participants to memorize an array of objects and their locations on a grid, one at a time. Participants with some control were permitted to reveal the objects themselves.

“They could inspect whatever they wanted, however they wanted, in whatever order for however much time they wanted, and they were just told to memorize everything on the screen,” Voss said. The “passive” learners instead reviewed a replay of the grid movements recorded in a previous trial by an active subject.

To complete the exercise the subjects tried to replicate the layout of the objects in the grid from memory. The active and passive subjects then changed roles and performed the task again with a new set of objects.

Recording significant differences in brain activity in the active and passive learners, Cohen and Voss found that the learners with had active control remembered the object placement significantly more accurately than the passive learners.

The researchers repeated the trials with people suffering memory impairment due to hippocampal damage. Surprisingly, these learners failed didn’t benefit from actively controlling the viewing window.

“These data suggest that the hippocampus has a role not just in the formation of new memory but possibly also in the beneficial effects of volitional control on memory,” the researchers wrote.

Confirming this hypothesis, further tests with fMRI showed the highest hippocampal activity in the active subjects’ brains. These tests also showed greater engagement in several other brain structures when the subject controlled the viewing window, and greater synchronization of activity in these brain regions and the hippocampus than in the passive trials.

Activity in the dorsolateral prefrontal cortex, the cerebellum and the hippocampus was higher, and more highly coordinated, in participants who did well on spatial recall, the researchers found. Increased activity in the inferior parietal lobe, the parahippocampal cortex and the hippocampus corresponded to better performance on item recognition.

“Lo and behold,” Cohen said, “our friend the hippocampus makes a very conspicuous appearance in active learning.”

The new findings challenge previous ideas about the role of the hippocampus in learning, Voss said. It is a surprise, he said, that other brain regions that are known to be involved in planning and strategizing, for instance, “can’t do very much unless they can interact with the hippocampus.”

Rather than being a passive player in learning, the hippocampus “is more like an integral part of an airplane guidance system,” Voss said. “You have all this velocity information, you have a destination target and every millisecond it’s taking in information about where you’re headed, comparing it to where you need to go, and correcting and updating it.”

The paper:
“Hippocampal Brain-network Coordination During Volitional Exploratory Behavior Enhances Learning.”

Neurogenesis & Addiction

Sunday, February 28th, 2010

Novel research at UT Southwestern Medical Center hints at new hope in combating addiction and dependence. The researchers’ experiments indicate that stimulating an increase in neurogenesis (brain cell growth) might help prevent addiction, dependence, or relapse. This is fascinating in the context of intensive brain training with programs such as Brain Fitness Pro.

Parallel studies show that intensive working memory training stimulates neurogenesis. Further, my own experience and the anecdotal experiences of Mind Sparke customers indicates that the training helps improve impulse control, self esteem, and elevate mood.

Published in the Journal of Neuroscience, the UT team’s work is the first research to directly link addiction with neurogenesis in the hippocampus.

“More research will be needed to test this hypothesis, but treatments that increase adult neurogenesis may prevent addiction before it starts, which would be especially important for patients treated with potentially addictive medications,” said Dr. Amelia Eisch, senior study author and associate professor of psychiatry at UT Southwestern. “Additionally, treatments that increase adult neurogenesis during abstinence might prevent relapse.”

Dr. Eisch and her team radiated rats’ brains to stop neurogenesis in the hippocampus. In one experiment, rats accessed cocaine by pressing a lever. The rats with radiated brains took more cocaine than rats that did not receive radiation.

In a second experiment, after becoming accustomed to taking cocaine the team radiated the rats, stopping neurogenesis while drugs were removed. Rats with reduced neurogenesis took more time to realize that the lever would no longer dispense cocaine.

“The nonirradiated rats didn’t like the cocaine as much and learned faster to not press the formerly drug-associated lever,” Dr. Eisch said. “In the context of this experiment, decreased neurogenesis fueled the process of addiction, instead of the cocaine changing the brain.”

Dr. Eisch plans to study other drugs of abuse, using imaging technology to study addiction and hippocampal neurogenesis in humans.

“If we can create and implement therapies that prevent addiction from happening in the first place, we can improve the length and quality of life for millions of drug abusers, and all those affected by an abuser’s behavior,” she said.

Exercise Makes Your Brain Bigger

Sunday, February 21st, 2010
Aerobic Exercise Increases Hippocampal Volume

Aerobic Exercise Increases Hippocampal Volume

In a study that focused specifically on patients suffering from schizophrenia, but also observing changes in non-schizophrenics, scientists have found that aerobic exercise increases the volume of the hippocampus by as much as 16%.

The volume increased by 12% in those with schizophrenia and by 16% in those without and was associated with improvements in short-term memory test scores.
“These results indicate that in [these patients], hippocampal volume is plastic in response to aerobic exercise,” write Frank-Gerald Pajonk, MD, Dr. K. Fontheim’s Hospital for Mental Health, Liedenburg, Germany, and colleagues.

“To provide a context, the magnitude of these changes in volume was similar to that observed for other subcortical structures when patients were switched from typical to atypical antipsychotic drug therapy,” they add.

“To be honest, we’ve been surprised that we found these results,” Dr. Pajonk told Medscape Psychiatry. “We double and tripled checked it, but the results were always confirmed. To our knowledge, this is the first time that it has been shown that the hippocampus is growing in patients with schizophrenia with a suitable method.

“As the hippocampus is one of the core structures in schizophrenia, we were thinking that if there was an increase in volume, it could give some improvement in cognition. And that’s what we found, at least to a small extent,” he added.

We’ve done this same study in other brain structures and did not find any volume increases,” said Dr. Pajonk. “So this really seems to be a result that is specific to the hippocampus. That means it’s not just a question of blood flow or unspecific factors, but maybe it’s really specific for development of neurons in terms of increase in synapses or even neurogenesis.”

He added that it may be too soon to draw any clinical conclusions.

The investigators hope to continue to follow up these patients and are awaiting funding for a new study comparing the effects of exercise with cognitive training.

“Although I can’t prove it right now, I’m positive that exercise is doing good in the treatment of schizophrenia,” said Dr. Pajonk. “Many of the schizophrenia patients from the sporting groups were able to go on and develop a life of their own, moving to a new apartment, taking up a job again, etc. It’s a bit early and we just had a small sample size, but with this small number of patients, we were really surprised and amazed at what has happened to them.”

From Arch Gen Psychiatry. 2010;67:133-143.

Also see:

Schizophrenia Improved By Mental And Physical Exercise

Effects of Physical Exercise & Schizophrenia

Brain Food | Diet And Brain Power

Saturday, December 5th, 2009

Brain food! New research indicates that particular foods can influence neurogenesis, leading to a greater proliferation of new nerve cells in particular regions of the brain.

The study focused on polyunsaturated fatty acids, derived from vegetables such as corn, soybeans, sunflowers and pumpkins as well as blue fish, and polyphenols found in tea, grapes, wine, olive oil, cocoa, nuts and other fruits and vegetables.

Spanish scientists from Universitat Autonoma de Barcelona who fed mice a diet rich in polyunsaturates and polyphenols noted greater cell proliferation in the two areas of the brain where neurogenesis is produced—the olfactory bulb and the hippocampus. (These areas become severely damaged in patients with Alzheimer’s disease, suggesting that a diet rich in these antioxidants could delay the onset or slow down the progress of this neurodegenerative disease.)

Neurogenesis And Memory

Tuesday, November 17th, 2009

Kaoru Inokuchi, a neuroscientist at the University of Toyama in Japan, and his team have shown that new brain cells in the hippocampus help clear away short term memories that have been passed along to long term storage.

It’s been known for a while that the hippocampus stores memories for a while then lets them go. Some memories make it into long term memory, some don’t. For a while, memories can be stored both in long term memory and the hippocampus.

Inokuchi and his colleagues suppressed neurogenesis in rats after inducing a “shock” memory. They found that the rats accessed hippocampal memory to remember the “shock” response. In contrast, rats with normal neurogenesis accessed long term memory for the shock response, indicating that neurogenesis had helped displace the “shock” memory from the hippocampus.

It had been previously theorized that neurogenesis helped form and consolidate memories in the hippocampus, but things now seem more complex.

“Our findings do not necessarily deny the important role of neurogenesis in memory acquisition,” Inokuchi says. “Hippocampal neurogenesis could have both of these roles, in erasing old memories and acquiring new memories.”

Hippocampal Neurogenesis: Proof of Long Term Rewiring

Tuesday, March 10th, 2009

Scientists from Tubingen, Germany have been able to demonstrate long term plastic change in the learning centers of the brain — specifically they focused on an area involved in memory and spacial awareness. The study used stimulation and magnetic resonance imaging to show that changes in the hippocampus resulted in changes in the activation of broad areas of the brain.

I’m posting this here because it connects yet another link in the chain of growing evidence supporting the idea that brain training can lead to long term brain change. The recent Swedish study by the team from the Karolinska Institutet showed that working memory training results in neurogenesis. And now we have the conclusion that plastic change (intrinsically linked to neurogenesis) leads to long term restructuring in large areas of the brain.

Long Term Brain Restructuring - Before and After

Brain Activity Before And After Plastic Change