Neuroscience Blog

Brain - Neuroscience Research Team.

Thursday, November 12, 2009

Jellyfish Nervous System - a short introduction

Posted by brain - research neuroscience group

see a larger version of the animation in high quality here

The nerve rings found  in cnidarians  can be considered one  of the first attempts of centralisation and an adaptation to the radial form . An interesting type of neurons in Cnidarians are those with giant axons. Giant axons are distinguishable from normal axons by their large diameter and relatively high speed of  signal conduction.
This giant axons form the motor giants and the ring giants in many jellysh species. Regarding the circuitry, Aglantha has the most complicated nervous system (in the jellyfish group). Also it seems that neuroendocrinology has much to reveal in this animal group, showing an unexpected complexity. Also, the giant axons in A. digitale can conduct
two types of action potentials: Ca2+ spikes and Na + spikes. Ca2+ spikes are generated during 
slow swimming, while Na + spikes are generated during the escape behavior. Na+ spikes are generated by fast-rising excitatory postsynaptic potentials (PSPs) representing input from the ring giant (RG) axon, while Ca2+ spikes arise from slow PSPs representing input from the pacemaker (P) system. Also, Mackie and Meech (1995) demonstrated the existence of two sets of interneurons, the relay and carrier systems. They transfer information from the pacemaker neurons to the tentacle action system during slow swimming. There is also a rootlet system which was first described by Weber et al. (1982). Also there is a small axon bundle connecting the margin and manubrium and it is a possible pathway that mediates the feeding behaviour in some species. In A. digitale, between the margin and the manubrium, there is an E system . This E system - that lies in the immediate vicinity of the endodermal radial canals - mediates lip aring, while the F system lies in the ectoderm. The F system is overlying the radial canals and mediates pointing [1]. The endodermal epithelium itself is an excitable tissue. In P. penicillatus, in the endodermal epithelium the impulses are transmitted via gap junctions (King and Spencer, 1979). This may also be true in Aglantha. A bundle of small axons runs up the subumbrella from the margin. They are placed close to the motor giant axon. The small axon bundles follow the motor giant path, then their course continue around the apex, head down the peduncle and enter the manubrium . Axons in these bundles show FMRFamide-like immunoreactivity (FaIR).

Electron microscopy failed to show synapses between the axons in the small axon
bundle or between them and other cells. The canals of the jellysh may be involved
in impulses transmission [2].
The ring giant lies in parallel with the much smaller axons (up to 6 fim) of the outer
nerve-ring and receives synaptic contacts from some of these. The ring giant axon is
covered, at the exterior, by a single layer (4-5 m thick) of epithelial cells [3].
The second type of giant axon runs from the margin up the inside of the bell in the
myoepithelium. They parallel each of the eight radial digestive canals. The term
used to call this nerve tracts is motor giant axons . Each motor giant axon is accompanied
by a number of smaller axons, some of which contribute to a nerve plexus in
the subumbrellar myoepithelium.
In jellysh there are two nerve rings: the subumbrellar inner nerve ring and the
exumbrellar outer nerve ring. Both nerve rings are found at the junction of the swimming
bell and the velum, a narrow ap of muscular tissue.

1 , 2, G. O. Mackie, R. M. Marx and R. W. Meech , Central circuitry in the jellysh Aglantha digitale IV. Pathways
coordinating feeding behaviour, The Journal of Experimental Biology 206, 2487-2505
3, Richard A. Satterlie, Control of swimming in the hydrozoan jellysh Aequorea victoria: subumbrellar
organization and local inhibition, The Journal of Experimental Biology 211, 3467-3477
--------------------------General bibliography--------------------
* Richard A. Satterlie, Control of swimming in the hydrozoan jellysh Aequorea victoria: subumbrellar organization
and local inhibition, The Journal of Experimental Biology 211, 3467-3477
* Richard A. Satterlie, Neuronal control of swimming in jellysh: a comparative story, Can. J. Zool. Vol. 80,
* G. O. Mackie, R. M. Marx1 and R. W. Meech, Central circuitry in the jellysh Aglantha digitale IV. Pathways
coordinating feeding behaviour , The Journal of Experimental Biology 206, 2487-2505
III. THE ROOTLET AND PACEMAKER SYSTEMS, The Journal of Experimental Biology 203, 1797–1807 (2000)

One month (until 12.12.09) of direct download as multipage PDF of this post here

Wednesday, September 23, 2009

Neuroscience 3D wallpapers Updates I

Posted by brain - research neuroscience group

New series of neuroscience / neurology/ neurosurgery wallpapers for your desktop :) Enjoy it!

Click on the image to enlarge it!

Find more 3D desktop wallpapers (neurology, neuroscience etc) .

Following the link ( to an older post on this blog) above you'll find interesting wallpapers and also a little application to find your monitor dimensions. Also you'll find some links about the way you can set up an image as a desktop wallpaper.

The wallpapers are posted in two dimensions - 1600X1200 px and 1440 X 900 px. Download the one that fits best your monitor.

Find more 3D art on
1600 X 1200 px
brain neuroscience 3D wallpaper desktop
brain, neuroscience, 3D, wallpaper, desktop

scientific desktop wallpaper
scientific, desktop, wallpaper

1440 X 900 px

scientific desktop wallpaper
scientific desktop wallpaper
medical wallpapers neuro
medical, wallpapers, neuro


New series of neuroscience / neurology/ neurosurgery wallpapers for your desktop :) Enjoy it!

1440 X 900 px

Every 3d image or photo on this blog are under blog owners copyright. You can download the images just for your personal usage. They cannot be posted on other sites unless you have my written permission. You cannot modify or use them as stock and you cannot sell them without blog owners written permission.

Saturday, August 08, 2009

The Color of Neurons or The Color of Success

Posted by brain - research neuroscience group

 (a) Is there a combination of colors that will make our neurons fire like never before? :)

Which are the colors of success? What color combination will make your art popular? Maybe the colors shown below.

Can neuroscience tell something about what color combination will make our neurons to fire faster? Small differences in hue, or luminosity can make us prefer an image or another, as below. Without talking about cultures, the subject of a painting or the composition of a 3D artwork, is there something in the hues that will make us stay longer in front of an artwork? Different hues activate different population of neurons. Is that why you prefer an image or another from the examples below?

Dozen of books can be written about the importance (or about the lack of importance) of hues in art, about their symbolism and the psychological effect. Our intention is to ask if there is something deeper inside of us that will choose an image or another as good because of the color used. Someone can say that the firs image is beautiful, but someone else can say that the second one is beautiful. Is this because of the color computations that take place in V1-V4 or in higher areas?
It is clear that in design (web design, print design, media) color matters. And all this fields mean high audience. In fine art different opinions were argued over time. Sometimes color is the ultimate way to express feelings , in other situations the color is just a third line instrument, and used just because it may fill some surfaces.

All of us have color preferences and sometimes a color palette in an artwork will make us appreciate more an artwork, sometimes a specific color combination will create repulsion. This are the personal preferences. But some artworks are so popular that it is very possible that will
create a pleasant effect to each new onlooker. In the image below we calculate the average color and the color palette used in some well known paintings.

A popular image will be as popular if the color palette changes? An artwork is popular or considered interesting or beautiful because of the idea, because of the way (line drawing, nonrepresentational/representational) it represents an idea or an attitude?
Has color something to do with all of this? We search some answers into the neurobiology of the visual cortex. One may say that the field of neuroaesthetics already has some answers, but we can respond there are many many factor that will obscure a clear conclusion even if we see the cortical areas activated by an artwork or even we can modulate the motivation or the attentional processes.

Without using too much advanced statistics or without assuming to create a scientific work, we made some observations by studying some popular images. We analyzed the color palette, the average color and the color distribution in different popular images and put the results side by side with the conclusions made by neuroscientists in the field of “color neurons” from the cortex.

It is generally accepted that the human visual cortex is tuned for natural images and the statistics of this images fit best the way we compute colors in our brain.

It is enough to create a color palette that will drive the brain to consider an artwork amazing?
It is not our intention to talk about images that use just the gray-scale palette because the neural mechanism for this kind of images might be different.

The main conclusion from our observations is that popular images contain a color palette that “fits” the statistics of “color tuned” neurons. On the other hand there are images that have nothing to do with this kind of “matching”, and to find an explanation maybe we have to search for patterns in higher brain areas or to think that the context in which an image is viewed has the greatest impact on the fate of that image. The context could mean the place, the cultural influence or the way of displaying it, but also the interaction between different neuronal networks in our brain, modulated by attention and experience.

Without having the intention to discuss here about what “beautiful” or “interesting” means for the field of neuroaesthetisc, we ask ourselves: an artwork that has a great impact on the lower visual areas will be more popular than an image that needs a lot of computation in different, interacting brain areas?

Is the color palette used, the first step to success? We selected using keywords the most popular images from and The same keywords were used for each site. The first 4-6 images displayed were considered to be “the most popular”. 73 images were collected. There are very many factors that act together to establish the ranking of an image. We consider this situation “as it is” and anlyzed the images in the terms of average color, color palette, color distribution etc. The images were calibrated and analyzed using the methods proposed on and Also a Fourier transformation was made for the “popular images” and for painting made by great painter. The two categories were compared.

We observed that the color distribution is similar with the color tuning prefference of the cortical neurons.

Many ideas and speculation coud be done starting from here, but further analysis should be done.
Anyway any color combination is great as long as the artist creation could transmit emotions and
ideas in the mind of the onlooker. The color palette used is very important because can determine one to select an image as beautiful or repulsive, but just a color combination will not have to much chances to become popular. Can anyone say that if an image is outside the "colors of success" will not be interesting or or popular? I don't think so... or... neurons never lie? :)

Wednesday, July 22, 2009

Neuroscience Desktop Wallpapers

Posted by brain - research neuroscience group

These days we've been working on some Neurology, Neuroscience, Brain theme wallpapers. Also we've made a little application for you to find your desktop (monitor) dimensions. Get the right image size for your monitor!

Click on the "0" in the application to get your monitor height and width. The wallpapers are in 2 dimensions formats: usual screen and wide screen. For example, if your monitor is 1024X768, it is best for you to choose the wallpaper in the 1600 X 1200 category. If your monitor is wide - 1360 X 768, it is best for you to choose the 1440 X 900 wallpaper category.

Click on the image---> then left click on your mouse----> "save image as", and choose the folder where you want to save the image. Then set up it as a desktop background. There are many ways to set up an image as wallpaper (desktop background). If you are not sure how to do it, I found on the net a clear tutorial here . Here is another very good tutorial.

Tehnical aspects (you may not need this details) : images for the wide screen are created to fit without distorsion on your wide monitor, keeping an 1:1 pixel aspect ration. So they simply have more pixels on the "X" axis. :), instead to be created with a different pixel aspect ratio. Our images are at 1:1 pixels aspect ratio. To find more about computer display go here (wikipedia). More on screens here

Finally, our team, proudly presents :) Claudiu's wallpapers

1600 X 1200 (or less) neuroscience, neurology wallpapers:neurology wallpaperneuroscience wallaper1440 X 900 (or less) Neurology, neuroscience, brain research wallpapers

neurology brain desktop wallpaperbrain research wallpaperCopyright: you can use these images for personal purposes. You are not allowed to sell, modify or use these images or parts of them in commercial purposes. You can redistribute these images or use them in public display as long as you keep the logos on the images. Link back to this post.

more 3D images and graphic design
or on 3D art graphic design portofolio

Thursday, July 16, 2009

Spinal Cord Injury, Dendritic Spines and Rac 1

Posted by brain - research neuroscience group

Spinal cord injury (SCI) could determine dendritic spines remodeling and can contribute to neuronal hyperexcitability and neuropathic pain through synaptic changes. Synaptic plasticity induced by SCI may appear in the spinal cord dorsal horn and may contribute to pain maintenance [1,2]. SCI increases Rac1 mRNA expression, which remains elevated for up to 3 months [3]. A role of Rac1, in neuropathic pain after SCI is not studied enough. Rac1 can modulate dendritic spine morphology and function [4, 5]. Andrew M. Tan et al (2008) applied the Rac1-speci­fic inhibitor NSC23766 in order to study the effect of synaptic remodeling in neuropathic pain after SCI. Rac1-speci­fic inhibitor NSC23766 blocks guanine exchange factors (GEFs), Trio and Tiam1. Inhibition of the Rac1 signaling cascade ameliorated the development of abnormal spine morphologies, reduced neuronal excitability, and normalized nociceptive thresholds. [6] PSD-95 expression is a marker of sites of synapse plasticity. Expression of PSD-95 is increased signifi­cantly in injured spinal cord tissue compared with uninjured controls [6]. NSC23766 treatment reduces PSD-95 levels below that of uninjured levels . Cortactin levels did not signifi­cantly change after NSC23766 treatment compared with intact animals. Dendritic spine density increases after SCI. In SCI plus veh animals (0.9% saline), the density of spines signifi­cantly shift toward the cell body compared with the spine density distribution in intact animals. An increase in spine density and redistribution of spine location relative to the cell body, and increases in spine length and head diameter after SCI occurs after SCI in dorsal horn neurons.

1 .Woolf CJ, Shortland P, Coggeshall RE (1992) Peripheral nerve injury triggers central sprouting of myelinated afferents. Nature 355:75–78.
2. Kim BG, Dai HN, McAtee M, Vicini S, Bregman BS (2006) Remodeling of synaptic structures in the motor cortex following spinal cord injury. Exp Neurol 198:401– 415.
3. Erschbamer MK, Hofstetter CP, Olson L (2005) RhoA, RhoB, RhoC, Rac1, Cdc42, and Tc10 mRNA levels in spinal cord, sensory ganglia, and corticospinal tract neurons and long lasting specific changes following spinal cord injury. J Comp Neurol 484:224 –233.
4. Nakayama AY, Harms MB, Luo L (2000) Small GTPases Rac
and Rho in the maintenance of dendritic spines and branches in hippocampal pyramidal neurons. J Neurosci 20:5329–5338.
5. Wiens KM, Lin H, Liao D (2005) Rac1 induces the clustering of AMPA receptors during spinogenesis. J Neurosci 25:10627–10636.
6. Andrew M. Tan, Severine Stamboulian, Yu-Wen Chang, Peng Zhao, Avis B. Hains,2 Stephen G. Waxman, and Bryan C. Hains, Neuropathic Pain Memory Is Maintained by Rac1-Regulated Dendritic Spine Remodeling after Spinal Cord Injury, The Journal of Neuroscience, 28(49):13173–13183 13173

For more about the relation between

Spinal cord injury and Rac1 ,

Dendritic Spines and PSD ,

Rho family of GTPases,

Actin Regulatory Pathways,

Dorsal Horn Neuronal Network and

Medication in SCI see the flash presentation bellow.

For a proper display you need FLASH PLAYER 8 or HIGHER !!!

Download the content of the presentation as A4 multipage PDF
or as A0 (high resolution) poster in PDF format Design 1
Design 2 or Design 3

You can also find Spinal Cord Injury and Dendritic Spines on Scribd as A4 multipage PDF
or download (if you have an account) Dendritic Spines Medical Print Design in A0 PDF format