Are there indeed “Right-Brained” or “Left-Brained” Personality Traits?

24 08 2013

Posted By Neuroscience News 

Chances are, you’ve heard the label of being a “right-brained” or “left-brained” thinker. Logical, detail-oriented and analytical? That’s left-brained behavior. Creative, thoughtful and subjective? Your brain’s right side functions stronger —or so long-held assumptions suggest.

But newly released research findings from University of Utah neuroscientists assert that there is no evidence within brain imaging that indicates some people are right-brained or left-brained.

For years in popular culture, the terms left-brained and right-brained have come to refer to personality types, with an assumption that some people use the right side of their brain more, while some use the left side more.

Following a two-year study, University of Utah researchers have debunked that myth through identifying specific networks in the left and right brain that process lateralized functions.

The image shows the hemispheric lateralization maps for the hubs of the brain. The caption best describes the image.

The hemispheric lateralization maps for the nine hubs of the left-lateralized network and 11 hubs of the right-lateralized network are shown in lateral and medial projections. Color scale (t-statistic) shows significantly left-lateralized (warm colors) or right-lateralized (cool colors) to the seed (i.e., hub). A black circle marks the position for each seed. Image and caption credited to Jared A. Nielsen et al in PLOS ONE.

Lateralization of brain function means that there are certain mental processes that are mainly specialized to one of the brain’s left or right hemispheres. During the course of the study, researchers analyzed resting brain scans of 1,011 people between the ages of seven and 29. In each person, they studied functional lateralization of the brain measured for thousands of brain regions —finding no relationship that individuals preferentially use their left -brain network or right- brain network more often.

“It’s absolutely true that some brain functions occur in one or the other side of the brain. Language tends to be on the left, attention more on the right. But people don’t tend to have a stronger left- or right-sided brain network. It seems to be determined more connection by connection, ” said Jeff Anderson, M.D., Ph.D., lead author of the study, which is formally titled “An Evaluation of the Left-Brain vs. Right-Brain Hypothesis with Resting State Functional Connectivity Magnetic Resonance Imaging.” It is published in the journal PLOS ONE this month.

Researchers obtained brain scans for the population they studied from a database called INDI, the International Neuroimaging Data-Sharing Initiative. The participants’ scans were taken during a functional connectivity MRI analysis, meaning a participant laid in a scanner for 5 to 10 minutes while their resting brain activity was analyzed.

By viewing brain activity, scientists can correlate brain activity in one region of the brain compared to another. In the study, researchers broke up the brain into 7,000 regions and examined which regions of the brain were more lateralized. They looked for connections — or all of the possible combinations of brain regions — and added up the number of connections for each brain region that was left- lateralized or right-lateralized. They discovered patterns in brain imaging for why a brain connection might be strongly left- or right-lateralized, said Jared Nielsen, a graduate student in neuroscience who carried out the study as part of his coursework.

“If you have a connection that is strongly left- lateralized, it relates to other strongly lateralized connection only if both sets of connections have a brain region in common,” said Nielsen.

Results of the study are groundbreaking, as they may change the way people think about the old right-brain versus left-brain theory, he said.

““Everyone should understand the personality types associated with the terminology ‘left-brained’ and ‘right-brained’ and how they relate to him or her personally; however, we just don’t see patterns where the whole left-brain network is more connected or the whole right-brain network is more connected in some people. It may be that personality types have nothing to do with one hemisphere being more active, stronger, or more connected,” said Nielsen.

Notes about this neuroimaging and neuropsychology research

Contact: Melinda Rogers – University of Utah Health System
Source: University of Utah Health System press release
Image Source: The image is credited to Jared A. Nielsen, Brandon A. Zielinski, Michael A. Ferguson, Janet E. Lainhart, and Jeffrey S. Anderson; and is adapted from the PLOS ONE open access research paper (doi:10.1371/journal.pone.0071275.g003).
Original Research: Full open access research for “An Evaluation of the Left-Brain vs. Right-Brain Hypothesis with Resting State Functional Connectivity Magnetic Resonance Imaging” by Jared A. Nielsen, Brandon A. Zielinski, Michael A. Ferguson, Janet E. Lainhart, and Jeffrey S. Anderson in PLOS ONE. Published online August 14 2013 doi:10.1371/journal.pone.0071275





Neurogenesis or why don’t we remember almost anything from when we were babies?

20 08 2013

By Thomas Insel, NIMH Director:

My four-year-old grandson has a near photographic memory for outings we took a year ago, for people he met six months ago, and for books he has not seen in weeks.  Soon that will all disappear.  By the time he is eight, he will remember almost nothing of his first four years.  And by the time he is eighteen, he will remember details going back to age four and he will retain language and habits acquired before age four, but in terms of autobiographical or episodic memories, the earliest years will be almost a complete blank.  This normal loss of early memories is called infantile amnesia.

Freud, a source not cited often in this space, was one of the first to write about infantile amnesia.  He attributed the loss of early memories to repression, an active forgetting of early experiences because of their heavily charged psychosexual content.  Others have explained infantile amnesia as due to the absence of language, since words seem important for encoding certain kinds of memory.   Still others have cited the need for a sense of self to provide a reference for early memory.

The problem with these explanations is that other mammals, lacking language and presumably less burdened by psychosexual conflicts, show the same loss of early memories while having perfectly good long-term memory for later experiences.  If mice and rats and other mammals also have infantile amnesia, what is the mechanism?  It’s not simply an inability to learn early in life.  Very young mammals, like my grandson, are sponges for information.  The problem is that this information is either not accessible or not retained in later development.

Recent research on this problem by Paul Frankland, Sheena Josselyn, and their colleagues at the Hospital for Sick Children in Toronto suggest a surprising explanation.1,2 They suggest that infantile amnesia is due to the rapid birth of cells in the hippocampus during infancy.  The hippocampus has long been known to be associated with episodic memory, including autobiographical memory.  And many scientists over the past two decades have shown that brain cells in the hippocampus continue to be generated through adulthood.  This process, called neurogenesis, occurs in humans as well as mice.  Many studies have shown that exercise increases neurogenesis, while stress decreases it.  And several investigators have suggested that neurogenesis is important for learning.

Frankland, Josselyn, and colleagues are suggesting paradoxically that neurogenesis is important for forgetting.  Specifically, they hypothesize that the increased rate of neurogenesis during infancy leads to loss of the memories that would otherwise be stored long-term.  What’s the evidence?  When they experimentally increase neurogenesis in adult mice, they induce a change in memory that looks like infantile amnesia.  And when they experimentally decrease neurogenesis in infant mice, they reduce the amnesia.  They have also studied mammals that are born relatively mature, like guinea pigs and degus.  These species do not have the rapid neurogenesis of infancy and do not show infantile amnesia.

Why is this important?  Beyond the mystery of why we lose our earliest memories, understanding a natural process like infantile amnesia can help us discern the fundamental connections between brain and behavior.  Do traumatic events (which presumably influence neurogenesis) get encoded and stored differently during infancy?  What about attachments in the first three years?  Do individual differences in neurogenesis translate into differences in recall?  Would changes in neurogenesis lead to changes in memory in humans?  All of these issues remain to be explored.  At this point we can say that a mystery that was fundamental to Freud’s theory of sexuality may now be solved with the tools of modern neuroscience.

References

1 Frankland PW, Köhler S, Josselyn SA. Hippocampal neurogenesis and forgettingTrends Neurosci. 2013 Jun 12. pii: S0166-2236(13)00086-6. doi: 10.1016/j.tins.2013.05.002. [Epub ahead of print]

2 Josselyn SA, Frankland PW. Infantile amnesia: a neurogenic hypothesis. Learn. Mem. 2012 19:423-433. Doi:10.1101/lm.021311.110.





“a sane reaction to insane circumstances”

11 08 2013

To all appearances, Eleanor Longden was just like every other student, heading to college full of promise and without a care in the world. That was until the voices in her head started talking. Initially innocuous, these internal narrators became increasingly antagonistic and dictatorial, turning her life into a living nightmare. Diagnosed with schizophrenia, hospitalized, drugged, Longden was discarded by a system that didn’t know how to help her. Longden tells the moving tale of her years-long journey back to mental health, and makes the case that it was through learning to listen to her voices that she was able to survive.

Eleanor Longden overcame her diagnosis of schizophrenia to earn a master’s in psychology and demonstrate that the voices in her head were “a sane reaction to insane circumstances.

 

To see & hear her talk at TED click HERE

 

EL





A survey on clinical applications of Neuropsychoanalysis

3 08 2013

 Dear Friends and Colleagues!

As we were preparing to the International Conference in Cape town:”Clinical applications of Neuropsychoanalysis”, we were reflecting on our practice.

This reflection ended by constructing a questionnaire that we now attach for you to enjoy. This survey is going all over the material worked through the last 14 years of discussions,

Research, and conferences trying to find out what was the benefit of all that endeavor to your practical clinical practice.

We made an online form and will be grateful if you will be able to take some moments from your time and add your words and choices.

You have to click on the link  and reply as you pass over the material. There is some space there to have your input to what we missed.

As this online questionnaire will be answered, we hope to present the statistics on our panel, led by Maggie Zellner, on Sunday morning.

Kind Regards,
 
Irith, Iftah and The Israeli Forum of Neuropsychoanalysis

https://docs.google.com/forms/d/1DmirPISn6llyAejZM-nnDs1qIBlyK0ogCGEYB2sfvzE/viewform