The Obese Brain May Thwart Weight Loss

New research by Terry Davidson, director of American University’s Center for Behavioral Neuroscience, indicates that diets that lead to obesity—diets high in saturated fat and refined sugar—may cause changes to the brains of obese people that in turn may fuel overconsumption of those same foods and make weight loss more challenging.

“It is a vicious cycle that may explain why obesity is so difficult to overcome,” said Davidson, also a professor of psychology at AU.

Davidson recently published his research, “The Effects of a High-Energy Diet on Hippocampal-Dependent Discrimination Performance and Blood-Brain Barrier Integrity Differ for Diet-Induced Obese and Diet-Resistant Rats,” in the journal Physiology & Behavior.

New study suggests memory impairment tied to object perception

A new study from Georgia Tech and the University of Toronto suggests that memory impairments for people diagnosed with early stage Alzheimer’s disease may be due, in part, to problems in determining the differences between similar objects. The findings also support growing research indicating that a part of the brain once believed to support memory exclusively – the medial temporal lobe - also plays a role in object perception. The results are published in the October edition of Hippocampus.

Mild cognitive impairment (MCI) is a disorder commonly thought to be a precursor to Alzheimer’s disease. The study’s investigators, partnering with the Emory Alzheimer’s Disease Research Center, tested MCI patients on their ability to determine whether two rotated, side-by-side pictures were different or identical.

Memory load leaves us ‘blind’ to new information

Trying to keep an image we’ve just seen in memory can leave us blind to things we are ‘looking’ at, according to the results of a study by researchers at the Institute of Cognitive Neuroscience.

It’s been known for some time that when our brains are focused on a task, we can fail to see other things that are in plain sight. This phenomenon, known as ‘inattentional blindness’, is exemplified by the famous ‘invisible gorilla’ experiment where people concentrate on a video of players throwing around a basketball and try to count the number of times the ball is thrown, but fail to observe a man in a gorilla suit walk across the centre of the screen.

The new results reveal that our visual field does not need to be cluttered with other objects to cause this ‘blindness’ and that focusing on remembering something we have just seen is enough to make us unaware of things that happen around us.

“An example of where this is relevant in the real world is when people are following directions on a Sat Nav whilst driving,” explains Professor Nilli Lavie from UCL Institute of Cognitive Neuroscience, who led the study. “Our research would suggest that focusing on remembering the directions we’ve just seen on the screen means that we’re more likely to fail to observe other hazards around us on the road, for example an approaching motorbike or a pedestrian on a crossing, even though we may be ‘looking’ at where we’re going.”

Chocolate makes snails smarter

University of Calgary undergraduate Lee Fruson became curious about how dietary factors might affect memory, Ken Lukowiak was sceptical. ‘I didn’t think any of this stuff would work’, Lukowiak recalls. Despite his misgivings, Lukowiak and Fruson decided to concentrate on a group of compounds – the flavinoids – found in a wide range of ‘superfoods’ including chocolate and green tea, focusing on one particular flavonoid, (-)epicatechin (epi). However, figuring out how a single component of chocolate might improve human memory is almost impossible – too many external factors influence memory formation – so Lukowiak turned to his favourite animal, the pond snail Lymnaea stagnalis, to find out whether the dark chocolate flavonoid could improve their memories.

Cogmed Working Memory Training: Does it Actually Work? The Debate Continues…

A target article in the Journal of Applied Research in Memory and Cognition concludes that evidence does not support the claims of Cogmed Working Memory Training. Additional experts weigh in with commentary papers in response.

Helping children achieve their full potential in school is of great concern to everyone, and a number of commercial products have been developed to try and achieve this goal. The Cogmed Working Memory Training program is such an example and is marketed to schools and parents of children with attention problems caused by poor working memory. But, does the program actually work? The target article in the September issue of Journal of Applied Research in Memory and Cognition (JARMAC) calls into question Cogmed’s claims of improving working memory and addressing underachievement due to working memory constraints.

The target article authors Zach Shipstead, Kenny L. Hicks, Randall W. Engle, all from the Georgia Institute of Technology, review the research that is used to back up the claims of Cogmed. They argue that many of the problem-solving or training tasks are not related to working memory, many of the attention tasks are unrelated to problems such as ADHD, and that there is limited transfer to real-life manifestations of inattentive behavior. They conclude succinctly: “The only unequivocal statement that can be made is that Cogmed will improve performance on tasks that resemble Cogmed training.”

How attention helps you remember: New study finds long-overlooked cells help the brain respond to visual stimuli

A new study from MIT neuroscientists sheds light on a neural circuit that makes us likelier to remember what we’re seeing when our brains are in a more attentive state.

The team of neuroscientists found that this circuit depends on a type of brain cell long thought to play a supporting role, at most, in neural processing. When the brain is attentive, those cells, called astrocytes, relay messages alerting neurons of the visual cortex that they should respond strongly to whatever visual information they are receiving.

The findings, published this week in the online edition of the Proceedings of the National Academy of Sciences, are the latest in a growing body of evidence suggesting that astrocytes are critically important for processing sensory information, says Mriganka Sur, the Paul E. and Lilah Newton Professor of Neuroscience at MIT and senior author of the paper.

Multiple Contacts Are Key to Synapse Formation

Multiple synaptic contacts between nerve cells facilitate the creation of a new contact, as neuroscientists from the Bernstein Center Freiburg and the Forschungszentrum Jülich report in the latest issue of the journal PLoS Computational Biology. An integral mechanism of memory foundation is the formation of additional contacts between neurons in the brain. However, until now it was not known what conditions lead to the development of such synapses and how they are stabilized once created. By studying mathematical models, the scientists found a simple explanation for how and when synapses form – or disappear – in the brain.

A team of neuroscientists and chemists from the U.S. and China September 24 publish research suggesting that a class of currently used anti-cancer drugs as well as several previously untested synthetic compounds show effectiveness in reversing memory loss in two animal models of Alzheimer’s disease.

CSHL Professor Yi Zhong, Ph.D., who led the research conducted in fruit flies and mice, says he and his colleagues were surprised with their results, which, he stressed, used two independent experimental approaches “the results of which clearly converged.”

Specifically, the research converged on what Zhong’s team suggests is a “preferred target” for treating memory loss associated with the amyloid-beta (Aβ) plaques seen in advanced Alzheimer’s patients. That target is the epidermal growth factor receptor, often called by its acronym, EGFR.

Overexpression of the EGFR is a characteristic feature of certain cancers, notably a subset of lung cancers.  Two targeted treatments, erlotinib (Tarceva) and gefitinib (Iressa), can dramatically, albeit transiently, reverse EGFR-positive cancers, by blocking the EGF receptor and thus preventing its activation.

The newly published research by Zhong’s team suggests that the signaling within cells that is induced by EGFR activation also plays a role in the pathology – still poorly understood – involved in Aβ-associated memory loss seen in Alzheimer’s patients.