The more we look, the more we understand that the human brain retains a remarkable ability to learn and re-fashion itself well into old age. The old idea that young brains are flexible, but that age causes us to become “hard-wired” and inflexible is not correct.

This has been confirmed in some new research that has just been published in the journal Neuron by investigators from Johns Hopkins who have shown that adult neurons are not glued in place as rigidly as had been thought.

The investigators led by David Linden used a new technique known as two-photon microscopy that allowed them to living neurons at work in the intact brain. The researchers injected fluorescent dye into the brains of mice to illuminate a subset of neurons and then viewed these neurons through a window in the skull of living, anesthetized mice.

They examined neurons that extend axons to the cerebellum, a region of the brain involved in coordinating motor and sensory information. These axons have a primary trunk that runs upward and several smaller branches that sprout out to the sides.

While the main trunk was firmly connected to other target neurons in the cerebellum, the side branches were mobile: Linden describes them like this:

“The side branches swayed like kite tails in the wind.”

Over the course of a few hours, individual side branches would highly dynamic behavior, elongating, retracting and morphing. These side branches also failed to make conventional synaptic connections with adjacent neurons. The motion of the side branches was arrested stalled by a drug that produced strong electrical currents in the axons.

Why the brain would want such motile, non-connected branches remains a mystery.

They may provide a second mechanism for conveying information beyond traditional synapses. Alternatively they may be involved in nerve regeneration.

Whatever the final answer, it is clear that the adult brain remains a remarkably plastic, fluid and flexible structure.

Excellent news for all of us!

“That which is flexible and flowing will prosper and grow. That which is rigid and blocked will wither and die.”
–Tao D Ching

“When a noble life has prepared old age, it is not decay that it reveals, but the first days of immortality.”
–Muriel Spark (Scottish Writer, 1918-)

“You will stay young as long as you learn, form new habits and don’t mind being contradicted.”
–Marie, Baronin von Ebner-Eschenbach (a.k.a. Baroness Marie von Ebner-Eschenbach, Austrian Writer, 1830-1916)

There are many mysteries about the human brain. One is the role of the cerebellum that lies at the back of your head right underneath the cerebral hemispheres. Most students believe that it is only involved in balance and motor coordination, but that does not make much sense: relative to the rest of the brain, humans have the largest cerebellum of any species apart form the dolphin. And there are good reasons for believing that it is involved in the coordination of emotional and social processes, as well as language.

We now learn that it may have yet another function. Colleagues from Washington University School of Medicine in St. Louis report that there is a sophisticated neural computer that is buried deep in the cerebellum, that performs inertial navigation calculations to calculate our precise movement through space.

These calculations are incredibly complex and involve the vestibular system in the inner ear that provides the primary source of input to the brain about the body’s movement and orientation in space. However, the vestibular sensors in the inner ear only give us information about the position of our head position. In addition the vestibular system’s detection of head acceleration cannot distinguish between the effect of movement and that of gravitational force.

Dora Angelaki and her team based their brain studies on the predictions of a theoretical mathematical model. The model proposed that the brain could calculate inertial motion by combining two things:
1. Rotational signals from the semicircular canal in the inner ear with
2. Gravity

Based on previous research, they concentrated their search for the brain’s inertial navigation system on particular types of neurons called Purkinje cells, in a region of the cerebellum known to receive signals from the vestibular system. This region is known as the posterior cerebellar vermis, a narrow, worm-like structure between the brain’s hemispheres. It has been known for two centuries that damage to the cerebellar vermis can produce bizarre neurological problems.

In their experiments, the researchers measured the electrical activity of these Purkinje cells in monkeys as the animals’ heads were maneuvered through a precise series of rotations and accelerations. After analyzing the electrical signals measured from the Purkinje cells during these movements, the researchers concluded that the specialized Purkinje cells were, as predicted, computing earth-referenced motion from head-centered vestibular information.

This is a remarkable finding: the cells are able to make complex deductions based on very little information.

Cells in the brain, particularly cells of the Purkinje type are designed to adapt and learn. So the finding gives yet more credence to the idea that balance, coordination and orientation in space are learnable skills. That will be the topic of another research project.

But for now, the evidence suggests that anything that helps you to practice these skills will likely pay dividends as you get older.

The two main kinds of meditation that have received a lot of research attention are Zen and Transcendental Meditation. Both produce measurable physiological changes and both may produce changes in the brain.

Zen meditation is centered on attentional and postural self-regulation.

As we age, there is normally some decline of cerebral gray matter volume and attentional performance. As I have pointed out, those changes do not necessarily mean a decline in functioning, but simply a change.

In a new study researchers here in Atlanta examined how the regular practice of meditation might affect the brain. The researchers studied 13 regular practitioners of Zen meditation and 13 matched controls.

They used some sophisticated techniques to calculate the volumes of different regions of the brain. They also performed a computerized sustained attention task.

While the control subjects showed the expected negative correlation of both gray matter volume and attentional performance with age, the meditators did not show a significant correlation of either measure with age.

Interestingly, the effect of meditation on gray matter volume was most prominent in a region of the brain called the putamen, a system of the brain that is strongly implicated in attentional processing.

These findings are intriguing and are consistent with some of the research done in Richard Davidson’s laboratory in Wisconsin, that looked at people practicing a different form of meditation, but also showed that expert meditators produce both structural and functional changes in their brains.

The study on aging suggests that the regular practice of meditation may have neuroprotective effects and reduce the cognitive decline associated with normal aging.

If that is confirmed, I think that we have something else to add to our list of “things to do to reduce your risk of getting Alzheimer’s.”

For centuries, people in cultures throughout the world have believed that increasing age is associated with increasing wisdom. Not just knowledge and experience, but wisdom. Is this an old wives’ tale, or is there something to it?

There is growing evidence that as we age our brains actually become stronger. Everyone missed it, because the emphasis was on memory, concentration and thinking speed, and those may all deteriorate with age. What changes is that as we age we become more efficient at making associations rather than thinking linearly. we also recruit regions of the brain that may have lain dormant for years. At the same time, different types of mental training, including meditation, can improve many aspects of our cognitive abilities, and may also enrich and even grow appropriate regions of the brain.

Some new data from a study being conducted at Wake Forest University Baptist Medical Center in North Carolina suggests that it is possible to use a fitness program for your brain that can improve thinking skills, attention and concentration as reliably as lifting weights can increase muscle strength.

Preliminary findings from the study, which used functional magnetic resonance imaging (fMRI) to record brain activity, were presented last week at the Organization for Human Brain Mapping conference in Chicago.

As we age, we do experience changes in how we perceive the information that our senses gather from the environment. As I mentioned older adults combine information from the different senses more readily than do younger adults. This is known as sensory integration, and the down side is that it can lead to difficulties in blocking out distracting sights and sounds while still maintaining focus on important information. You are probably familiar with the “Cocktail Party Phenomenon.” You are in a loud room, but because someone is saying something interesting, you are able to block out uninteresting information. This technical term for this is cortricofugal inhibition. As we get older it gets more difficult to do the inhibiting.

The Brain Fitness in Older Adults (B-fit) study has been designed to establish whether eight hours of brain exercise can improve the ability of healthy older adults, ages 65 to 75 years, to filter out unwanted sights and sounds.

The B-fit study uses fMRI to visualize blood flow and brain activity to determine how attention training affects brain function. The training involves either a structured one-on-one mental work-out program or a group brain exercise program. During the one-on-one sessions, the volunteers were asked to ignore distracting information and tasks get harder as the eight-week training progresses. For the group sessions, participants learn new information relevant to healthy aging and are then tested on their ability to apply the new information.

All participants had an fMRI scan during a distraction task. They had to look for target words or numbers while ignoring distracting sounds. The scans showed brain activity in areas related to both sight and sound. Follow-up fMRIs showed that in the group receiving the one-on-one training, activity related to sight was increased, while activity related to sound was decreased. In addition, performance on the task was improved.

So the data do indeed suggest that attention training is a way to reduce
older adults’ susceptibility to distracting stimuli and therefore help improve
concentration.

And what about wisdom?

I have written in Healing, Meaning and Purpose that “Wisdom is the integration of understanding:” making more new associations and drawing conclusions based on a new perspective is a gift of aging. The training enables us to make sense of and communicate our conclusions.

When it comes to the brain, use it or lose!

One of the most promising changes in psychology is the ever-greater emphasis on what makes us healthy, rather than constantly looking at the things that make us sick. There is an important approach called Behavioral Activation (BA) Theory, which emphasizes environmental and behavioral factors as determinants of our overall well-being. According to the theory, reduced engagement in pleasurable activities may be an important precursor of reduced well-being. This makes good sense: it is estimated that as much as 90% of our higher cortical functions are designed for social interactions.

This is something that I wrote in Healing, Meaning and Purpose:

“Nothing in the Universe exists in isolation: We live in a Universe of relationships. It is inconceivable that anything can exist except in relationship to something else. The entire Universe is made up of integrated systems that function, develop and evolve together. A failure to construct and maintain healthy relationships can be a cause of much distress.

Several years ago I reported some interesting observations. At the time, I was doing a lot of research on diseases of blood vessels. I had developed a laboratory method for taking some of the cells that line blood vessels from volunteers and then growing them in a cell culture dish. We discovered that if we did not have enough cells in the dish, they would all die of “loneliness.” The exception is cancer cells, which in culture will grow on their own, like weeds.”

As an example in a paper published in February in the Archives of General Psychiatry it was shown that lonely individuals may be twice as likely to develop the type of dementia linked to Alzheimer’s disease in late life as those who are not lonely. The theory has been shown to predict psychiatric well-being in a number of populations, including the caregivers of people with Alzheimer’s disease, people with chronic pain, cancer patients and community-dwelling older people.

It is also known that psychiatric well-being, particularly emotional well-being, may play an important role in cardiovascular health. This may be due to an increase in the activity of the sympathetic nervous system that increases not only blood pressure, but also the levels of inflammatory mediators and coagulant factors in the blood.

In research from the University of California at La Jolla that was presented on Monday at the 2007 Annual Meeting of the American Psychiatric Association in San Diego, California, twenty two people with a mean age of 70 were studied, to see if there was a link between their behavioral activation, i.e. how satisfied they were with their leisure activities, their affective well-being and their blood pressure.

The findings were as expected: the less satisfied and engaged people were, the higher was their blood pressure.

This is only preliminary data, but it confirms something that we have said before: as we get older it is as important to stay socially engaged as it is to do mental exercise.

And if you known someone who is older and isolated, you might want to go and see them.

“The most terrible poverty is loneliness and the feeling of being unloved.”
–Mother Teresa of Calcutta (Albanian-born Indian Nun, Humanitarian and, in 1979, Winner of the Nobel Peace Prize, 1910-1997)

“What makes loneliness an anguish is not that I have no one to share my burden, but this: I have only my own burden to bear.”
–Dag Hammarskjöld (Swedish Statesman, Secretary-General of the United Nations from 1953-1961, and, in 1961, Winner of the Nobel Peace Prize, 1905-1961)