Findings Friday: The aging brain is a distracted brain

As the brain ages, it becomes more difficult for it to shut out irrelevant stimuli—that is, it becomes more easily distracted. Sitting in a restaurant, having a conversation with your table partner right across the table from you, presents as a new challenge when the restaurant is buzzing with activity.

However, the aging brain does not have to be the distracted brain. Training the mind to shut out irrelevant stimuli is possible, even for the older brain.

Brown University scientists conducted a study involving seniors and college-age students. The experiment was a visual one.

Participants were presented with a letter and number sequence, and asked to report only the numbers, while simultaneously disregarding a series of dots. The dots sometimes moved randomly, and at other times, moved in a clear path. The latter scenario makes the dots more difficult to ignore, as the eye tends to want to watch the dots move.

The senior participants tended to unintentionally learn the dot motion patterns, which was determined when they were asked to describe which way the dots were moving. The college age participants were better able to ignore the dots, and focus on the task at hand (the numbers).

Another study also examined aging and distractibility, or an inability to maintain proper focus on a goal due to attention to irrelevant stimuli. Here, aging brains were trained to be more focused. The researchers used older rats, as well as older humans. Three different sound were played during the experiment, with a target tone presented. Awards were given when the target tone was identified and the other tones ignored. As subjects improved, the tasks became challenging, with the target tone becoming less distinguishable to from the other tones.

However, after training, both the rats and the humans made fewer errors. In fact, electrophysiological brain recordings indicated that neural responses to the non-target, or distracting, tones were decreased.

Interestingly, the researchers indicated that ignoring a task is not the flip side of focusing on a task. Older brains can be just as efficient at focusing as younger brains. The issue in aging brains, however, lies in being able to filter out distractions. This is where training comes in: strengthening the brain’s ability to ignore distractors; not necessarily enhancing the brain’s ability to focus.

The major highlights of the study include training older humans with respect to enhanced aspects of cognitive control, and the adaptive distractor training that sought to selectively suppress distractor responses.


The Pain in Brain Stays Mainly in the…Brain?

Pain is a major force of survival. Without pain, we would, simply, not survive. Of course, pain can be cumbersome, and unnecessary, at times. For example, when you stub your toe on your desk, do you really need that much pain for that long?

More importantly to this discussion, what do you do when you stub your toe? Probably do a bit of hopping, and you certainly grab that toe and squeeze or rub it.

Why do you do that? The Gate Control Theory of Pain can answer that.

At its basic, the Gate Theory of Pain dictates that non-painful input (like that rubbing) closes the gates to painful input. This results in the prevention of the sensation of pain from being fully perceived by the brain. Simply, when the painful stimulus is overridden by a non-painful stimulus, the pain sensation does not travel to the central nervous system (CNS).

Even more simply, non-painful stimuli suppress pain.

Why is that?

Collaterals, or processes, of large sensory fibers that carry cutaneous (skin) sensory input activate inhibitory interneurons. Now, inhibitory interneurons do just what their name implies: they inhibit. And what do they inhibit in this case? Pain sensory pathways. This therefore modulates the transmission of pain information by pain fibers. Non-painful input suppresses pain by “closing the gate” to painful input.

This happens at the spinal cord level: non-painful stimulation will result in presynaptic inhibition on pain (nociceptive) fibers that synapse on nociceptive spinal neurons. This inhibition, which is presynaptic, will therefore block any incoming painful stimuli from reaching the CNS.

More on this topic on this week’s Séance Sunday, coming up!

Findings Friday: Super brain

Everyone’s been talking about the effects of meditation on the brain. Since it is such a healthy part of daily living and can work wonders on cognitive skills, including learning, memory, and creativity, I do think it is important to give a brief overview of the benefits meditation has on cognition.

The meditation to be analyzed is simple breath meditation, with or with a mantra. No om’s necessary.

A study done by Newberg, et al., 2010, tested whether those with memory loss would demonstrate changes in their memory and cerebral blood flow (CBF) after an 8-week meditative program. “Fourteen subjects with memory problems had an IV inserted and were injected with 250 MBq of Tc-99m ECD while listening to a neutral stimulus CD. They then underwent a pre-program baseline SPECT scan. ”

Basically, what this means is that 14 subjects with memory loss were injected with a dye used in brain imaging studies (the dye is radioactive; sounds more frightening than it actually is. It helps in imaging blood flow). The subjects then had their brains imaged as a baseline.

“Then subjects were guided through their first meditation session with a CD, during which they received an injection of 925 MBq ECD, and underwent a pre-program meditation scan. Subjects completed an 8-week meditation program and underwent the same scanning protocol resulting in a post-program baseline and meditation scan. “

In other words, the subjects underwent guided meditation, where someone guides through breathing, posture, etc.. The subjects were injected with the imaging dye and had baseline imaging done. They then underwent an 8-week meditation program, then had their brains imaged once more.

The results: CBF was increased to the brain areas responsible for cognition, including the prefrontal cortex. Memory was also found to increase after meditative training.

Another study by Zeidan, et al., 2010, found that even brief meditation can be effective:

After four sessions of either meditation training or listening to a recorded book, participants with no prior meditation experience were assessed with measures of mood, verbal fluency, visual coding, and working memory. Both interventions were effective at improving mood but only brief meditation training reduced fatigue, anxiety, and increased mindfulness. Moreover, brief mindfulness training significantly improved visuo-spatial processing, working memory, and executive functioning. Our findings suggest that 4days of meditation training can enhance the ability to sustain attention; benefits that have previously been reported with long-term meditators.”

In other words, even short sessions and for a shorted duration can affect cognition positively, enhance mood and overall allow for a better functioning brain.

There a number of other studies that indicate similar things. Whether a novice meditator or a seasoned one, meditation can affect cognition positively, and enhance even mood, making the meditator a better, happier thinker.

Don’t believe me, here are several more studies:

Moore and Malinowski, 2009

Kaszniak, chapter excerpt

Friese, et al., 2012

And Jon Kabat-Zinn, who propelled the west into meditation, speaks here:

Findings Friday: Lucid Dreamers

Who wouldn’t want to lucid dream,–be aware of oneself when dreaming, and able to control the dream? I sure would. I experienced it once, and needless to say, the experience left me craving more.

There are techniques to enable yourself to lucid dream. They will be discussed in a future article.

This article, however, will focus on the lucid dreamers themselves.

Lucid dreamers may be more self-reflective than the general population, a new study conducted at the Max Planck Institute of Psychiatry at Munich has indicated.

It was found that the anterior prefrontal cortex, which is involved in controlling conscious cognitive processes and plays a role in self-reflection, is larger in lucid dreamers than in non-lucid dreamers. This suggests that metacognition and lucid dreaming are closely connected.

Brain scans taken of subjects solving metacognitive tests while awake indicated that brain activity in the prefrontal cortex was higher in lucid dreamers than non-lucid dreamers. The researchers thus concluded that those who can lucid dream are more self-reflective in daily life.

The researchers want to go further and determine whether metacognitive skills can be trained.

Now, of course, correlation does not mean causation. And just because a brain region shows activity does not necessarily mean that brain area is involved in a particular process being studied. It may very well be that the brain region being activated during an activity is actually shutting down other processes. So, this study is a good preliminary one, but as is always said, more research needs to be done.

Findings Friday: The brain can help you burn fat

With many individuals pronouncing “losing weight” as their new years’ resolutions (I’m one of those individuals, I might add), here is some interesting new research:

The brain may instruct the body to burn more fat.

Now, around our bodies, fat is stored in fat cells, or adipocytes. This is called “white fat”. Around our necks, however, is “brown fat”, which may be induced to burn fat. The mechanism involves two hormones, leptin and not surprisingly, insulin. Leptin functions as an appetite suppressant, while insulin, of course, regulates glucose levels. Both hormones work together to stimulate fat-burning by stimulating a group of neurons in the hypothalamus (which regulate hunger and thirst, among other things) to induce fat-burning mechanisms.

The process is regulated by phosphatases, which are enzymes that inhibit leptin and insulin. Now, when these enzymes are inhibited, more fat is burned because the fat is not converted to white fat,but rather, brown fat, which then leads to excess fat being burned off.

[Fun fact: Where does fat go when it’s burned? Now, you may think it escapes via body heat, or is “burned off” by being released as body heat, but in fact, fat is burned by being released as CO2].