Why living in the moment is impossible.

Contribution by WiSci

The sought-after equanimity of “living in the moment” may be impossible, according to neuroscientists who’ve pinpointed a brain area responsible for using past decisions and outcomes to guide future behavior.

The study, based on research conducted at the University of Pittsburgh and published August 9 in the professional journal Neuron, is the first of its kind to analyze signals associated with metacognition — a person’s ability to monitor and control cognition (a term cleverly described by researchers as “thinking about thinking.”)

“The brain has to keep track of decisions and the outcomes they produce,” said Marc Sommer, who did his research for the study as a University of Pittsburgh neuroscience faculty member and is now on the faculty at Duke University. “You need that continuity of thought,” Sommer continued. “We are constantly keeping decisions in mind as we move through life, thinking about other things. We guessed it was analogous to working memory, which would point toward the prefrontal cortex.”

Sommer predicted that neuronal correlates of metacognition resided in the same brain areas responsible for cognition, including the frontal cortex — a part of the brain linked with personality expression, decision making, and social behavior. Sommer worked with Paul G. Middlebrooks, who did his research for the study at Pitt before he received his Pitt PhD in neuroscience in 2011; Middlebrooks is now a postdoctoral fellow at Vanderbilt University. The research team studied single neurons in vivo in three frontal cortical regions of the brain: the frontal eye field (associated with visual attention and eye movements), the dorsolateral prefrontal cortex (responsible for motor planning, organization, and regulation), and the supplementary eye field (SEF) involved in the planning and control of saccadic eye movements, which are the extremely fast movements of the eye that allow it to continually refocus on an object.

To learn where metacognition occurs in the brain, subjects performed a visual decision-making task that involved random flashing lights and a dominant light on a cardboard square. Participants were asked to remember and pinpoint where the dominant light appeared, guessing whether they were correct. The researchers found that while neural activity correlated with decisions and guesses in all three brain areas, the putative metacognitive activity that linked decisions to bets resided exclusively in the SEF.

“The SEF is a complex area [of the brain] linked with motivational aspects of behavior,” said Sommer. “If we think we’re going to receive something good, neuronal activity tends to be high in SEF. People want good things in life, and to keep getting those good things, they have to compare what’s going on now versus the decisions made in the past.”

Sommer noted that defining such concepts related to metacognition, like consciousness, has been difficult for decades. He sees his research and future work related to studying metacognition as one step in a systematic process of working toward a better understanding of consciousness. By studying metacognition, he says, he reduces the big problem of studying a “train of thought” into a simpler component: examining how one cognitive process influences another.

“Why aren’t our thoughts independent of each other? Why don’t we just live in the moment? For a healthy person, it’s impossible to live in the moment. It’s a nice thing to say in terms of seizing the day and enjoying life, but our inner lives and experiences are much richer than that.”

So far, patients with mental disorders have not been tested on these tasks, but Sommer is interested to see how SEF and other brain areas might be disrupted in these disorders.

“With schizophrenia and Alzheimer’s disease, there is a fracturing of the thought process. It is constantly disrupted, and despite trying to keep a thought going, one is distracted very easily,” Sommers said. “Patients with these disorders have trouble sustaining a memory of past decisions to guide later behavior, suggesting a problem with metacognition.”

Funding for this research was provided by the University of Pittsburgh, the joint University of Pittsburgh-Carnegie Mellon University Center for the Neural Basis of Cognition, the National Institute of Mental Health, and the Alfred P. Sloan Foundation.

The above story is reprinted from materials provided by University of Pittsburgh.

Journal Reference:
1.Paul G. Middlebrooks, Marc A. Sommer. Neuronal Correlates of Metacognition in Primate Frontal Cortex. Neuron, 2012; 75 (3): 517 DOI: 10.1016/j.neuron.2012.05.028

Can depression and stress hurt the brain?

Major depression or chronic stress can cause the loss of brain volume, a condition that contributes to both emotional and cognitive impairment. Now a team of researchers led by Yale scientists has discovered one reason why this occurs — a single genetic switch that triggers loss of brain connections in humans and depression in animal models.

The findings, reported in the Aug. 12 issue of the journal Nature Medicine, show that the genetic switch known as a transcription factor represses the expression of several genes that are necessary for the formation of synaptic connections between brain cells, which in turn could contribute to loss of brain mass in the prefrontal cortex.

“We wanted to test the idea that stress causes a loss of brain synapses in humans,” said senior author Ronald Duman, the Elizabeth Mears and House Jameson Professor of Psychiatry and professor of neurobiology and of pharmacology.

“We show that circuits normally involved in emotion, as well as cognition, are disrupted when this single transcription factor is activated.”

The research team analyzed tissue of depressed and non-depressed patients donated from a brain bank and looked for different patterns of gene activation. The brains of patients who had been depressed exhibited lower levels of expression in genes that are required for the function and structure of brain synapses. Lead author and postdoctoral researcher H.J. Kang discovered that at least five of these genes could be regulated by a single transcription factor called GATA1. When the transcription factor was activated, rodents exhibited depressive-like symptoms, suggesting GATA1 plays a role not only in the loss of connections between neurons but also in symptoms of depression.

Duman theorizes that genetic variations in GATA1 may one day help identify people at high risk for major depression or sensitivity to stress.

“We hope that by enhancing synaptic connections, either with novel medications or behavioral therapy, we can develop more effective antidepressant therapies,” Duman

Migraines hurt your head and not your brain.

Contribution by ScienceDaily (Aug. 10, 2012)

Migraines currently affect about 20 percent of the female population, and while these headaches are common, there are many unanswered questions surrounding this complex disease. Previous studies have linked this disorder to an increased risk of stroke and structural brain lesions, but it has remained unclear whether migraines had other negative consequences such as dementia or cognitive decline. According to new research from Brigham and Women's Hospital (BWH), migraines are not associated with cognitive decline.

This study is published online by the British Medical Journal (BMJ) on August 8, 2012. "Previous studies on migraines and cognitive decline were small and unable to identify a link between the two. Our study was large enough to draw the conclusion that migraines, while painful, are not strongly linked to cognitive decline," explained Pamela Rist ScD, a research fellow in the Division of Preventive Medicine at BWH, and lead author on this study.

The research team analyzed data from the Women's Health Study, a cohort of nearly 40,000 women, 45 years and older. In this study, researchers analyzed data from 6,349 women who provided information about migraine status at baseline and then participated in cognitive testing during follow-up. Participants were classified into four groups: no history of migraine, migraine with aura (transient neurology symptoms mostly of the visual field), migraine without aura, and past history of migraine. Cognitive testing was carried out in two year intervals up to three times.

"Compared with women with no history of migraine, those who experienced migraine with or without aura did not have significantly different rates of cognitive decline," explained Rist. "This is an important finding for both physicians and patients. Patients with migraine and their treating doctors should be reassured that migraine may not have long term consequences on cognitive function."

There is still a lot that is unknown about migraines. However this study offers promising evidence for patients and their treating physicians. More research needs to be done to understand the consequences of migraine on the brain and to establish strategies to influence the course of the disease in order to optimize treatment strategies.

This research was supported by The Women's Health Study is supported by grants from the National Heart, Lung, and Blood Institute (HL-043851, HL-080467, HL-099355) and the National Cancer Institute (CA-47988). The cognitive substudy of the Women's Health Study was supported by a grant from the National Institute of Aging (AG-15933). PMR was supported by a training grant from the National Institute of Aging (AG-00158). TK is supported in part by a Chair of Excellence grant of the French National Research Agency (Agence Nationale de la Recherche, R09177DD).