Posts Tagged ‘Anterior cingulate cortex’

Brain Activity Underlying the Placebo Effect

August 21, 2013

Research that conducted brain imaging during placebo studies found that both the active (opiod) treatment and the placebo (saline) treatment activated the same network of brain regions. This included the brain stem, a part of the opiod system that mediates pain relief, and the rostral anterior cingulate cortex, which is rich in opiod receptors.1 It is also a part of the body’s reward system. The researcher, Petrovic, proposed that placebos, like opiods, triggered control areas such as the anterior cingulate that exerted control over the analgesic systems of the brain stem. The analgesic systems of the brain stem then released endorphins.

Another researcher, Tor D. Wager, who also used MRI found that additional brain systems were involved in the placebo effect. The researchers administered a placebo cream while giving painful shocks or painful intense heat on the forearms of the research participants. In one experiment a warning cue, a red “get ready” sign was given just before the painful stimulus was administered. The research subjects expected pain, unless the cream was applied, in which case they expected relief. The expectation of relief activated the cognitive executive center of the brain, the prefrontal cortex. Then the pain response areas of the brain declined, and the experimental participants reported relief. These results suggest that the placebo pain relief involves an expectaton signal from the prefrontal cortex that orders the midbrain to release opiods to meet the expectation of reprieve. Absent this, the full experience of pain is perceived. Further research has pinpointed specific regions of the prefrontal cortex as drivers.

Emotions are also involved in the placebo effect. Wager and his colleagues reported in 2011 that activities in regions of the brain that perform emotional appraisal, such as the insula, orbitofrontal cortex, and amygdala accompany a robust placebo effect. Wager calls this endogenous regulation. Placebos seem to give us a better perspective on our predicament. We might reevaluate our predicament so that we believe that the pain will abate and not cause persistent disability. According to Wager, during a placebo response, “our brain is likely doing a lot of the work without our real conscious input or even in spite of our conscious desires.” That is, we unconsciously engage brain mechanisms that serve to sooth.

Ironically, this self-soothing process might require us to focus on the pain rather than something else. In another study by Wager and his colleagues published in 2012, they tried to distract people away from experimentally induced pain by having them perform another task. This other task did not help relieve the pain. But when the researchers encouraged the participants to pay attention to the heat on their arm by asking them to rate its intensity, the participants experienced greater relief. This result is consistent with “acceptance” therapies or with the “relaxation response” in which people surrender to their pain to tolerate it better.

1The facts in this blog post can be found in an article, When Pretending is the Remedy, in Scientific American Mind, March/April 2013 by Trisha Gura.

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Self-Affirmation Rather Then Self-Esteem

April 28, 2013

This post is largely based on an article by Sharon Begley, “To Love You Is to Know You,” published in the June issue of Mindful magazine. The importance of self-esteem was emphasized in the 1980s. All sorts of benefits were supposed to accrue to those with high self-esteem. Consequently programs were developed to enhance self-esteem. I remember being criticized by a student in her course evaluation for my having damaged her self-esteem. Although I had given the student a solid “A” in the course, she said that her self-esteem had suffered due to her getting several incorrect answers on an exam.

Subsequent research has debunked the benefits of self-esteem. Although programs to build self-esteem might build self-esteem in individuals, this self-esteem does not manifest itself in better performance in school or work, in particular, and in life, in general. Fortunately a new concept has emerged to replace the concept of self-esteem. This new concept is self-affirmation. The simplest way to think of self-affirmation is as self-esteem absent the “I’m wonderful” component. Another way of thinking of self-affirmation is as “mindfulness of the self.” According to the article, “Self-affirmation is the process of reminding yourself of the values and interests that constitute your true or core self.”

Research into self-affirmation has shown that self-affirmation can not only reduce the anxiety and defensiveness that usually arise when we make mistakes, but it can also help us to learn from our mistakes so that we do better the next time. Self-affirmation makes us less defensive when receiving threatening information, be it negative feedback from a supervisor, criticism from a loved one, or poor performance. We become more open to opposing views and more self-controlled.

A study done by the psychologist Lisa Legault provides some insight as to the mechanisms underlying the benefits of self-affirmation. Two groups of college students were provided different instructions. One group performed an exercise to foster self-affirmation; the control group performed an exercise that did not foster self-affirmation. Both groups performed the same simple task: to press a button whenever an “M” appeared on a computer screen for one-tenth of a second. If a “W” appeared, they were to refrain from pushing the button. Brain activity was monitored when they performed this task. The group given the self-affirmation instructions made fewer errors of commission, pressing the button when the “W” appeared (7% vs. 12.4%). The more important result was the difference in brain activity. There is a brain wave that occurs when a mistake is made called error-related negativity (ERN). This ERN is generated by the anterior cingulate cortex, which is involved in detecting errors, anticipating rewards, and being emotionally aware. It generates the feeling that a mistake was made. It has a strong emotional component and is why we feel bad when we mess up. The more we care, the stronger the ERN that results when we fail or receive criticism. In this study, the self-affirmation group had stronger ERN waves than the control group. It appears that this enhanced response to the task resulted in better performance.

In view of these results, it becomes clear why self-esteem is ineffective. A person with high self-esteem might not care how well he does. He already thinks that he is great. Similarly, a person with high self-esteem is likely to reject criticism because he thinks he is great. The result is that learning does not occur. Now a person with self-affirmation will have among her core beliefs that she is capable of succeeding, but is open to criticism and failure as the means to success. Mistakes will feel more troublesome, but that results in more attention and better learning.

Insight

February 27, 2013

According to Costa, the author of The Watchman’s Rattle: A Radical New Theory of Collapse, what will save us all is the ability of the human mind to achieve insight. She writes of insight as it it is a new discovery. The notion of insight and an “aha” moment in solving problems goes back to the Gestalt psychologists at least. What is new is the identification cognitive structures involved in achieving insight.

Costa stresses that insight is a biological capability that we all have. She cites an article1 that describes an experiment in which the cognitive structures were identified. Nineteen experimental participants were asked to solve word problems while the activity in their brains was monitored. Three words were presented, such as pine, crab, and sauce, to each participant. The task was to think of another word that could be combined with each of these words to make three new words. For example, a solution to these words would be “apple,” to produce “pineapple,” “crabapple,” and “applesauce.” The participants did many of these problems and brain activity was tracked to identify and differences that signaled an insightful answer. When insight was used the anterior Superior Temporal Gyrus (aSTG) became highly excited producing a sudden burst of gamma oscillatory activity. This occurred 300 milliseconds in advance of solving the problem. They also discovered that the Anterior Cingulate Cortex (ACG), which is responsible for relaying signals between the left and right hemispheres of the brain, appears to suppress irrelevant thoughts prior to invoking insight. The notion is that insightful thinking is more vulnerable to external interference than is nonsightful processing necessitating greater suppression of external thoughts. When insight is achieved, the problem solver is confident of her insight. Insight is cognitively taxing. Increased electrical activity takes place in the left posterior M/STG, the anterior cingulate, the right posterior M/STG, and the amygdala. Costa argues that insight is the brain’s special weapon against complexity. A simplifying insight eliminates the complexity.

Insight and creativity are closely related. I would suggest that insight is a special type of creativity, one aimed and solving a particular problem. Insight is creative, but creativity also includes literature, fine art, music, and dance to name just a few activities.

1 Kouinios, J.K., Frymiare, J.L., Bowden, e.M., Fleck, J.I., Subramanaiam,K, Parrish, T.B., & Jung-Beeman, M. (2006). The Prepared Mind: Neural Activity Prior to Problem Presentaion Predicts Subsequent Solution by Sudden Insight. Psychological Science, 17:882, DOI:10.111/j.1467-9280.2006.01798.

© Douglas Griffith and healthymemory.wordpress.com, 2012. Unauthorized use and/or duplication of this material without express and written permission from this blog’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Douglas Griffith and healthymemory.wordpress.com with appropriate and specific direction to the original content.

SuperAgers with a Super Memory

October 3, 2012

In a recent experiment1 SuperAgers were defined as individuals over 80 with episodic memory performance at least as good as normative values for 50- to 65-year olds. The performance of these SuperAgers was compared to two cognitively normal cohorts: age-matched elderly and 50- to 65-year olds. The brains of all three groups were compared using cortical morphometry.

With respect to memory performance, the SuperAgers performed better than both control groups (but the difference between the SuperAgers and the middle-age controls was not statistically significant, p>0.05). The sample consisted of 12 SuperAgers, 10 elderly controls, and 14 middle-age controls. The elderly control group performed significantly worse than the other two groups.

With respect to whole-brain cortical thickness elderly controls exhibited significant atrophy in the older cohort compared against the middle-aged controls in multiple regions across the frontal, parietal, and occipital lobes, including medial temporal regions important for memory. However, the whole brain cortical thickness analysis comparing the SuperAgers with the middle-aged controls did not reveal significant atrophy in the SuperAgers.

With respect to the thickness of the Anterior Cingulate Cortex, the thickness of the SuperAgers was higher than both the Elderly Controls and the Middle-Aged Controls. Somewhat surprisingly, only the difference between the SuperAgers and the Middle-Aged controls was statistically significant (p<0.05). However, the likelihood of achieving statistical significance increases as sample size increases. Research has indicated that the cingulate constitutes a critical site of transmodel integration related to episodic memory, spatial attention, cognitive control, and motivational modulation. It is unclear whether the SuperAgers were born with a particularly thick cortex or whether they resisted cortical change over time.

The relationship between brain and memory is an interesting one. The notion that more brain equates to more memory is fairly common, but this finding needs to be placed in context. Alzheimer’s cannot be diagnosed conclusively until an autopsy has been done. The key signatures for the diagnosis are amyloid plaques and neurofibrillary tangles. But these same signatures have been found in autopsies of people WHO HAD SHOWN NO SYMPTOMS OF ALZHEIMER’S WHEN THEY WERE ALIVE! So it would appear that these amyloid plaques and neurofibrillary tangles are a necessary, but not a sufficient condition for Alzheimer’s.

I remember reading an article when I was in graduate school about someone who had hydroencephalocele, which is more commonly called “water in the brain.” As a result of this condition, this individual had only about 10% of the normal volume of cortex. Yet this person led a normal life and earned a Bachelor of Science Degree in mathematics!

The plasticity of the brain is truly remarkable. Healthymemory believes that this plasticity is fostered by cognitive exercise and cognitive challenges. So, stay cognitively active and seek cognitive growth!

1Harrison, T.M., Weintraub, S., Mesulam, M.-M, & Rogalski, E. (2012). Superior Memory and Higher Cortical Volumes in Unusually Successful Aging, Journal of the International Neuropsychological Society, 18, 1-5.

© Douglas Griffith and healthymemory.wordpress.com, 2012. Unauthorized use and/or duplication of this material without express and written permission from this blog’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Douglas Griffith and healthymemory.wordpress.com with appropriate and specific direction to the original content.

VENs: the Key to Consciousness?

July 28, 2012

VENs stands for Von Economo Neurons. Constantin von Economo was the neuroscientist who discovered these neurons.1 VENs are quite distinctive in appearance. They are at least 50 per cent and sometimes up to 200 percent larger that typical neurons. They have a long spindly cell body with a single projection at each end and very few branches. They are quite rare. They make up just about one per cent of the neurons in two small areas of the brain: the anterior cingulate cortex (ACC) and the fronto-insular (FI) cortex. The ACC and FI are heavily involved in many of the more advanced aspects of cognition and feeling. They make up a social monitoring network that keeps track of social cues so that we can react appropriately.

The ACC and FI keep a subconscious tally of what is going on around us and direct attention to the most important events as well as monitoring sensations from the body to detect any changes. Both these brain regions are active when we recognize our reflection in a mirror. This suggests that these parts of the brain underlie our sense of self. It is a key component of consciousness providing a sense of self identify and a sense of the identity of others. They provide the sense of how we feel.

The notion is that VENs provide a fast relay system, a kind of social superhighway that allows the gist of a situation to move quickly through the brain, enabling us to react intuitively. This is a crucial survival skill in social species such as our own. VENs are also found in social mammals.

People with fronto-temporal dementia lose large numbers of VENs in the ACC and FI early in the disease. The main symptom of the diseases is a complete loss of social awareness, empathy, and self-control.

According to one study2 people with autism fall into two groups. One group consists of those who have too few VENs, so they might not have the necessary wiring to process social cues. The other group consists of those who have far too many VENs. Having too many VENS might make emotional systems fire intensely, causing people with autism to feel overwhelmed.

Another study3 found that people with schizophrenia who committed suicide had significantly more VENs in their ACC than schizophrenics who died of other causes, The notion is that the over-abundance of VENs might create an overactive emotional system that leaves them prone to negative self-assessment and feelings of guilt and hopelessness.

Bud Craig, a neuroanatomist at Barrow Neurological Institute has pointed out that the bigger the brain, the more energy it takes to run, so it is crucial that it operates as efficiently as possible. He said, “Evolution produced an energy calculation system that incorporated not just the sensory inputs from the brain. And the fact that we are constantly updating this picture of “how I feel now” has an interesting and very useful by-product: we have a concept that there is an “I” to do the feeling. Evolution produced a very efficient moment-by-moment calculation of energy utilization that had an epiphenomenon, a by-product that provided a subjective representation of my feelings.”4

The author of the New Scientist article concludes “If he’s right—and there is a long way to go before we can be sure—it raises a very humbling possibility: that far from being the pinnacle of brain evolution, consciousness might been a big, and very successful accident.”5

Although I am excited by the possibility that the neurological basis of consciousness has been found, I am disturbed by their reductionist conclusions. Most of us assume that there is a neural basis for consciousness. But the finding of this neural basis does not prove that consciousness is an epiphenomenon (not real). The next post will provide evidence regard the reality and purpose of consciousness.

1Williams, C. (2012). The Conscious Connection. New Scientist, 21 July, 33-35.

3PloS One, vol 6, pe20936).

4Op cit.p. 35

5Ibid.

© Douglas Griffith and healthymemory.wordpress.com, 2012. Unauthorized use and/or duplication of this material without express and written permission from this blog’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Douglas Griffith and healthymemory.wordpress.com with appropriate and specific direction to the original content.