TROPICAL SYNAPSES
Reflections on topics including clinical neurology, recent publications in neuroscience,
philosophy of biology, "neuro-doubt" about modern media hype of new neuro-scientific procedures and methods, consciousness, scuba diving, horticulture, jazz, blues, slack key guitar music, the Hawai'i health scene, and whatever else dat's da kine...
New Concussion Guidelines: If In Doubt, Sit it Out
Cranial Vein Procedures Found Not Effective in Multiple Sclerosis
To the surprise of almost no one in North America, using a balloon catheter to correct small areas of vein narrowing when found in the heads of persons with MS does not help their multiple sclerosis, according to a small but (finally) well controlled trial. So far, I only have read a description of a poster presentation at the San Diego meeting this weekend, with nothing more on the details to read today. Hopefully a full paper will be vetted soon enough.
Those of us who were investigating new treatments back in the eighties will remember the Los Angeles surgeon who got in big trouble for performing vertebral artery surgery on MS patients over 25 years ago. Vascular theories of MS recur periodically, and given the distribution of the lesions, there may be a truth in there somewhere. But it is not likely to do with the kinds of arteries or veins one can fix with a knife or a catheter.
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POSTER
P04.273– “Percutaneous Transluminal Venous Angioplasty (PTVA) is Ineffective in Correcting Chronic Cerebrospinal Venous Insufficiency (CCSVI) and May Increase Multiple Sclerosis (MS) Disease Activity in the Short Term: Safety and Efficacy Results of the 6–Month, Double–Blinded, Sham–Controlled, Prospective, Randomized Endovascular Therapy in MS (PREMiSe) trial” – Robert Zivadinov, Buffalo, NY
Averaging and Contrast Artifacts on fMRI
Problems that occur via volume averaging and the noise increases with software-based upward adjustments of contrast have long been known to limit CT and MRI scans of the brain when looking at smaller regions for changes. fMRI researchers people are only now starting to notice this kind of artifact in their findings. This is a good sign, though, that the field may be maturing.
One further suggestion to help reliable anatomic localization is to replicate findings in other patients and with other equipment. There is still too little replication of scattered reports in the field.
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ABSTRACT
Matthew D. Sacchet, Brian Knutson, Spatial smoothing systematically biases the localization of reward-related brain activity, NeuroImage, Volume 66, 1 February 2013, Pages 270-277, ISSN 1053-8119, 10.1016/j.neuroimage.2012.10.056.
(http://www.sciencedirect.com/science/article/pii/S1053811912010592)
Neuroimaging methods with enhanced spatial resolution such as functional magnetic resonance imaging (FMRI) suggest that the subcortical striatum plays a critical role in human reward processing. Analysis of FMRI data requires several preprocessing steps, some of which entail tradeoffs. For instance, while spatial smoothing can enhance statistical power, it may also bias localization towards regions that contain more gray than white matter. In a meta-analysis and reanalysis of an existing dataset, we sought to determine whether spatial smoothing could systematically bias the spatial localization of foci related to reward anticipation in the nucleus accumbens (NAcc). An activation likelihood estimate (ALE) meta-analysis revealed that peak ventral striatal ALE foci for studies that used smaller spatial smoothing kernels (i.e. < 6 mm FWHM) were more anterior than those identified for studies that used larger kernels (i.e. > 7 mm FWHM). Additionally, subtraction analysis of findings for studies that used smaller versus larger smoothing kernels revealed a significant cluster of differential activity in the left relatively anterior NAcc (Talairach coordinates: − 10, 9, − 1). A second meta-analysis revealed that larger smoothing kernels were correlated with more posterior localizations of NAcc activation foci (p < 0.015), but revealed no significant associations with other potentially relevant parameters (including voxel volume, magnet strength, and publication date). Finally, repeated analysis of a representative dataset processed at different smoothing kernels (i.e., 0–12 mm) also indicated that smoothing systematically yielded more posterior activation foci in the NAcc (p < 0.005). Taken together, these findings indicate that spatial smoothing can systematically bias the spatial localization of striatal activity. These findings have implications both for historical interpretation of past findings related to reward processing and for the analysis of future studies.
Keywords: Nucleus accumbens (NAcc); Ventral striatum (VS); Spatial smoothing; Functional magnetic resonance imaging (fMRI); Reward; Monetary incentive delay (MID) task
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Aloha Friday: Ledward Kaapana
The classic Ku'uipo Onaona, here (youtube).
Appropriate for me, given that Maryruth is off on the mainland visiting relatives this week.
Ku`u Ipo Onaona - Madeline Lam
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Auhea wale `oe e ku`u ipo lâ Eia mai au ke kali nei lâ Mai lohi mai `oe e ku`u ipo lâ E ala wiki mai `oe `O `oe no ka`u i mana`o ai lâ He mea nui `oe na ka pu`uwai lâ Hau`oli au i kou leo nahenahe Kou leo me ke aloha Ka`a puni aku a puni ka honua lâ A `ike i ka nani o nâ pua like `ole `A`ole no e like me `oe E ku`u ipo onaona Ha`ina `ia mai ana ka puana lâ Eia mau au ke kali nei lâ Mai lohi mai `oe e ku`u ipo lâ E ala wiki mai `oe | Listen, my sweetheart, this is for you Here I wait Come, don't be slow, sweetheart Hurry to me You are always on my mind You overwhelm my heart Your gentle voice gives me pleasure Your voice of love I've travelled the world Seen the beauty of flowers rare None can compare to you My lovely sweetheart Tell the refrain Here I wait Come, don't be slow, sweetheart Hurry to me |
tDCS for writer's block?
tDCS stands for trans-cranial direct-current stimulation, which is being researched as a treatment for chronic pain and other disorders of brain function. An interesting feature of tDCS is its ability to subtly affect thinking styles, such as modifying a person's tendency to think over a choice versus making a more rapid decision.
Writer's block is a well known phenomenon in the history of literature. It is the otherwise unexplained inability of an accomplished writer to produce new work. Writer's block has been linked to anxiety and other distractions, but one theory of its cause is that a decision vetoing and supervisory function (maintained by the left frontal region) is causing excessive frontal inhibition. tDCS over the left PFC (pre-frontal cortex) region seems, according to the publication below, to tend to make decisions more impulsive and less inhibited. I would therefore expect that cathodic tDCS near the left frontal region might reduce writer's block, perhaps at the expense of the output needing extra revision later, if the left frontal inhibition theory is indeed correct.
The placebo effect should be useful, too, for that condition. Any volunteers?
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ABSTRACT
Noninvasive transcranial direct current stimulation over the left prefrontal cortex facilitates cognitive flexibility in tool use
DOI:10.1080/17588928.2013.768221 Evangelia G. Chrysikouab*, Roy H. Hamiltonc, H. Branch Coslettc, Abhishek Dattad, Marom Biksond & Sharon L. Thompson-Schilla
Received: 22 Oct 2012
Recent neuroscience evidence suggests that some higher-order tasks might benefit from a reduction in sensory filtering associated with low levels of cognitive control. Guided by neuroimaging findings, we hypothesized that cathodal (inhibitory) transcranial direct current stimulation (tDCS) will facilitate performance in a flexible use generation task. Participants saw pictures of artifacts and generated aloud either the object's common use or an uncommon use for it, while receiving cathodal tDCS (1.5mA) either over left or right PFC, or sham stimulation. A forward digit span task served as a negative control for potential general effects of stimulation. Analysis of voice-onset reaction times and number of responses generated showed significant facilitative effects of left PFC stimulation for the uncommon, but not the common use generation task and no effects of stimulation on the control task. The results support the hypothesis that certain tasks may benefit from a state of diminished cognitive control.
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Chimeras and Dr. Moreau
ABSTRACT
Forebrain Engraftment by Human Glial Progenitor Cells Enhances Synaptic Plasticity and Learning in Adult Mice
Xiaoning Han1, 2, Michael Chen1, 2, Fushun Wang1, 2, Martha Windrem1, 3, Su Wang1, 3, Steven Shanz1, 3, Qiwu Xu1, 2, Nancy Ann Oberheim1, 2, Lane Bekar1, 2, Sarah Betstadt4, Alcino J. Silva5, Takahiro Takano1, 2, Steven A. Goldman1, 2, 3, , and Maiken Nedergaard1, 2, 3, ,
1 Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY 14642, USA 2 Department of Neurosurgery, University of Rochester Medical Center, Rochester, NY 14642, USA 3 Department of Neurology, University of Rochester Medical Center, Rochester, NY 14642, USA 4 Department of Obstetrics and Gynecology, University of Rochester Medical Center, Rochester, NY 14642, USA 5 Departments of Neurobiology, Psychiatry and Psychology, Integrative Center for Learning and Memory, University of California, Los Angeles, David Geffen School of Medicine, Los Angeles, CA 90095, USA
Summary
Human astrocytes are larger and more complex than those of infraprimate mammals, suggesting that their role in neural processing has expanded with evolution. To assess the cell-autonomous and species-selective properties of human glia, we engrafted human glial progenitor cells (GPCs) into neonatal immunodeficient mice. Upon maturation, the recipient brains exhibited large numbers and high proportions of both human glial progenitors and astrocytes. The engrafted human glia were gap-junction-coupled to host astroglia, yet retained the size and pleomorphism of hominid astroglia, and propagated Ca2+ signals 3-fold faster than their hosts. Long-term potentiation (LTP) was sharply enhanced in the human glial chimeric mice, as was their learning, as assessed by Barnes maze navigation, object-location memory, and both contextual and tone fear conditioning. Mice allografted with murine GPCs showed no enhancement of either LTP or learning. These findings indicate that human glia differentially enhance both activity-dependent plasticity and learning in mice.
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The emerging problem is that we are on a slippery slope which terminates with Dr. Moreau's suffering hybrids.
There are already laws in most countries against chimeras creation on the level of Dr. Moreau, but there are also laws against human trafficking in countries where it routinely occurs. So there is going to be a problem here, sooner or later.
Coffee Enhances Honeybee Memory
(Photo of honeybee on arabica coffee flowers courtesy tonx, of flickr)
Research published in Science magazine online March 7, 2013 suggests that flowers can use caffeine content in their nectar to increase the chance of further pollination by enhancing memory in the sipping honeybees. New meaning for the term buzz?
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ABSTRACT
Science 8 March 2013: Vol. 339 no. 6124 pp. 1202-1204 DOI: 10.1126/science.1228806
REPORT Caffeine in Floral Nectar Enhances a Pollinator's Memory of Reward G. A. Wright1,*, D. D. Baker2, M. J. Palmer3, D. Stabler1,2, J. A. Mustard4, E. F. Power1,2, A. M. Borland2, P. C. Stevenson5,6
1Centre for Behaviour and Evolution, Institute of Neuroscience, Newcastle University, Newcastle upon Tyne NE1 7RU, UK. 2School of Biology, Newcastle University, Newcastle upon Tyne NE1 7RU, UK. 3Division of Neuroscience, Medical Research Institute, Ninewells Medical School, University of Dundee, Dundee DD1 9SY, UK. 4School of Life Sciences, Arizona State University, Tempe, AZ 85287, USA. 5Jodrell Laboratory, Royal Botanic Gardens, Kew, Surrey TW9 3AB, UK. 6Natural Resources Institute, University of Greenwich, Chatham, Kent ME4 4TB, UK. ↵*To whom correspondence should be addressed. E-mail: jeri.wright@ncl.ac.uk
Plant defense compounds occur in floral nectar, but their ecological role is not well understood. We provide evidence that plant compounds pharmacologically alter pollinator behavior by enhancing their memory of reward. Honeybees rewarded with caffeine, which occurs naturally in nectar of Coffea and Citrus species, were three times as likely to remember a learned floral scent as were honeybees rewarded with sucrose alone. Caffeine potentiated responses of mushroom body neurons involved in olfactory learning and memory by acting as an adenosine receptor antagonist. Caffeine concentrations in nectar did not exceed the bees' bitter taste threshold, implying that pollinators impose selection for nectar that is pharmacologically active but not repellent. By using a drug to enhance memories of reward, plants secure pollinator fidelity and improve reproductive success.
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You are what you eat?
Well, maybe your microbiome is about 3% exactly what you ate, at least. ABSTRACT =======================================================...
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According to the Nobel-prize-winning work in the 1960's by Sperry and Gazzaniga , after the two cerebral hemisphere are cut by callos...
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The Ship of Theseus is a classic thought experiment in Greek philosophy. As related by Plutarch the historian, Theseus' ship was kept as...
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Sanboukan sweet lemon citrus tree grafts after a month, unwrapped today. The first graft looks more solidly healed than the second. We wi...