The concept of a topographical map of the corpus callosum (CC) has emerged from human lesion studies and from electrophysiological and anatomical tracing investigations in other mammals. Over the last few years a rising number of researchers have been reporting functional magnetic resonance imaging (fMRI) activation in white matter, particularly the CC. In this study the scope for describing CC topography with fMRI was explored by evoking activation through simple sensory stimulation and motor tasks. We reviewed our published and unpublished fMRI and diffusion tensor imaging data on the cortical representation of tactile, gustatory, auditory, and visual sensitivity and of motor activation, obtained in 36 normal volunteers and in 6 patients with partial callosotomy. Activation foci were consistently detected in discrete CC regions: anterior (taste stimuli), central (motor tasks), central and posterior (tactile stimuli), and splenium (auditory and visual stimuli). Reconstruction of callosal fibers connecting activated primary gustatory, motor, somatosensory, auditory, and visual cortices by diffusion tensor tracking showed bundles crossing, respectively, through the genu, anterior and posterior body, and splenium, at sites harboring fMRI foci. These data confirm that the CC commissure has a topographical organization and demonstrate that its functional topography can be explored with fMRI.

Mara Fabri

Gabriele Polonara

Functional Topography of Human Corpus Callosum: An fMRI Mapping Study

The ubiquitin-proteasome system (UPS) is most widely known for its role in intracellular protein degradation; however, in the decades since its discovery, ubiquitination has been associated with the regulation of a wide variety of cellular processes.  The addition of ubiquitin tags, either as single moieties or as polyubiquitin chains, has been shown not only to mediate degradation by the proteasome and the lysosome, but also to modulate protein function, localization, and endocytosis.  The UPS plays a particularly important role in neurons, where local synthesis and degradation work to balance synaptic protein levels at synapses distant from the cell body.  In recent years, the UPS has come under increasing scrutiny in neurons, as elements of the UPS have been found to regulate such diverse neuronal functions as synaptic strength, homeostatic plasticity, axon guidance, and neurite outgrowth.  Here we focus on recent advances detailing the roles of the UPS in regulating the morphogenesis of axons, dendrites, and dendritic spines, with an emphasis on E3 ubiquitin ligases and their identified regulatory targets.

Andrew M. Hamilton

Karen Zito

Breaking It Down: The Ubiquitin Proteasome System in Neuronal Morphogenesis

In a recent article I reviewed an influential theory of sleep function, the &#x201c;synaptic homeostasis hypothesis (SHY.)&#x201d; According to SHY, sleep renormalizes synapses that are potentiated during prior wakefulness. I concluded that while SHY is a seminal theory with important implications about sleep function and the brain, its underlying mechanisms are poorly defined. In an accompanying article, the authors of SHY responded at length. Their reply is thoughtful and provocative, but unfortunately many of the points I raised were not accurately represented or addressed. In this brief commentary, I attempt to clarify some points of confusion. I also explain why any theory of sleep function is incomplete without an understanding of the underlying cellular mechanisms.

Marcos Gabriel Frank

Why I Am Not SHY: A Reply to Tononi and Cirelli

The human brain is made up of an extensive network of neurons that communicate by forming specialized connections called synapses. The amount, location, and dynamic turnover of synaptic proteins, including neurotransmitter receptors and synaptic scaffolding molecules, are under complex regulation and play a crucial role in synaptic connectivity and plasticity, as well as in higher brain functions. An increasing number of studies have established ubiquitination and proteasome-mediated degradation as universal mechanisms in the control of synaptic protein homeostasis. In this paper, we focus on the role of the ubiquitin-proteasome system (UPS) in the turnover of major neurotransmitter receptors, including glutamatergic and nonglutamatergic receptors, as well as postsynaptic receptor-interacting proteins.

Amy W. Lin

Heng-Ye Man

Ubiquitination of Neurotransmitter Receptors and Postsynaptic Scaffolding Proteins

<i  >Background</i>. The etiology of motor impairments in preterm infants is multifactorial and incompletely understood. Whether corpus callosum development is related to impaired motor function is unclear. Potential associations between motor-related measures and diffusion tensor imaging (DTI) of the corpus callosum in preterm infants were explored. <i  >Methods</i>. Eight very preterm infants (gestational age of 28&#x2013;32 weeks) underwent the Hammersmith neonatal neurological examination and DTI assessments at gestational age of 42 weeks. The total Hammersmith score and a motor-specific score (sum of Hammersmith motor subcategories) were calculated. Six corpus callosum regions of interest were defined on the mid-sagittal DTI slice&#x2014;genu, rostral body, anterior midbody, posterior midbody, isthmus, and splenium. The fractional anisotropy (FA) and mean diffusivity (MD) of these regions were computed, and correlations between these and Hammersmith measures were sought. <i  >Results</i>. Anterior midbody FA measures correlated positively with total Hammersmith (rho <svg     style="vertical-align:-0.20474pt;width:51.337502px;" id="M1" height="11.175" version="1.1" viewBox="0 0 51.337502 11.175" width="51.337502"  xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg">
	
		
			<g transform="matrix(.017,-0,0,-.017,.062,10.862)"><path id="x3D" d="M535 323h-483v50h483v-50zM535 138h-483v50h483v-50z" /></g><g transform="matrix(.017,-0,0,-.017,14.749,10.862)"><path id="x30" d="M241 635q53 0 94 -28.5t63.5 -76t33.5 -102.5t11 -116q0 -58 -11 -112.5t-34 -103.5t-63.5 -78.5t-94.5 -29.5t-95 28t-64.5 75t-34.5 102.5t-11 118.5q0 58 11.5 112.5t34.5 103t64.5 78t95.5 29.5zM238 602q-32 0 -55.5 -25t-35.5 -68t-17.5 -91t-5.5 -105&#xA;q0 -76 10 -138.5t37 -107.5t69 -45q32 0 55.5 25t35.5 68.5t17.5 91.5t5.5 105t-5.5 105.5t-18 92t-36 68t-56.5 24.5z" /></g><g transform="matrix(.017,-0,0,-.017,22.909,10.862)"><path id="x2E" d="M113 -12q-24 0 -39.5 16t-15.5 42q0 24 16 40.5t40 16.5t40 -16.5t16 -40.5q0 -26 -16 -42t-41 -16z" /></g><g transform="matrix(.017,-0,0,-.017,26.785,10.862)"><path id="x39" d="M244 635q90 0 143 -72t53 -177q0 -133 -65 -229.5t-171 -139.5q-79 -32 -140 -32l-5 30q109 18 185 91t101 186l-68 -36q-29 -16 -60 -16q-79 0 -129 51.5t-50 130.5q0 80 57 146.5t149 66.5zM228 602q-52 0 -78 -45.5t-26 -98.5q0 -69 36.5 -115.5t97.5 -46.5&#xA;q53 0 90 28q4 31 4 66q0 51 -9.5 95.5t-39 80.5t-75.5 36z" /></g><g transform="matrix(.017,-0,0,-.017,34.944,10.862)"><path id="x32" d="M412 140l28 -9q0 -2 -35 -131h-373v23q112 112 161 170q59 70 92 127t33 115q0 63 -31 98t-86 35q-75 0 -137 -93l-22 20l57 81q55 59 135 59q69 0 118.5 -46.5t49.5 -122.5q0 -62 -29.5 -114t-102.5 -130l-141 -149h186q42 0 58.5 10.5t38.5 56.5z" /></g><g transform="matrix(.017,-0,0,-.017,43.103,10.862)"><use xlink:href="#x39"/></g>

		
	
</svg>, <svg     style="vertical-align:-0.1638pt;width:66.875px;" id="M2" height="11.375" version="1.1" viewBox="0 0 66.875 11.375" width="66.875"  xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg">
	
		
			<g transform="matrix(.017,-0,0,-.017,.062,11.112)"><path id="x1D443" d="M619 482q0 -69 -40.5 -119t-96 -72.5t-118.5 -26.5h-44l-70 20l-31 -151q-14 -67 0.5 -83t89.5 -22l-5 -28h-287l8 28q65 7 81.5 22t29.5 83l79 398q12 56 0.5 70.5t-78.5 20.5l7 28h255q108 0 164 -43t56 -125zM524 478q0 141 -146 141q-25 0 -47 -8q-16 -6 -20.5 -13.5&#xA;t-10.5 -39.5l-43 -241q37 -13 83 -13q67 0 125.5 45t58.5 129z" /></g><g transform="matrix(.017,-0,0,-.017,15.582,11.112)"><use xlink:href="#x3D"/></g><g transform="matrix(.017,-0,0,-.017,30.286,11.112)"><use xlink:href="#x30"/></g><g transform="matrix(.017,-0,0,-.017,38.446,11.112)"><use xlink:href="#x2E"/></g><g transform="matrix(.017,-0,0,-.017,42.321,11.112)"><use xlink:href="#x30"/></g><g transform="matrix(.017,-0,0,-.017,50.481,11.112)"><use xlink:href="#x30"/></g><g transform="matrix(.017,-0,0,-.017,58.64,11.112)"><path id="x31" d="M384 0h-275v27q67 5 81.5 18.5t14.5 68.5v385q0 38 -7.5 47.5t-40.5 10.5l-48 2v24q85 15 178 52v-521q0 -55 14.5 -68.5t82.5 -18.5v-27z" /></g>

		
	
</svg>) and motor-specific scores (rho <svg     style="vertical-align:-0.1638pt;width:51.337502px;" id="M3" height="11.125" version="1.1" viewBox="0 0 51.337502 11.125" width="51.337502"  xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg">
	
		
			<g transform="matrix(.017,-0,0,-.017,.062,10.862)"><use xlink:href="#x3D"/></g><g transform="matrix(.017,-0,0,-.017,14.749,10.862)"><use xlink:href="#x30"/></g><g transform="matrix(.017,-0,0,-.017,22.909,10.862)"><use xlink:href="#x2E"/></g><g transform="matrix(.017,-0,0,-.017,26.785,10.862)"><path id="x38" d="M249 635q70 0 116 -43t46 -105q0 -46 -28 -80q-22 -25 -80 -64q62 -35 97 -75t35 -99q0 -81 -63 -131t-135 -50q-83 0 -137.5 45.5t-54.5 123.5q0 52 45 95q29 28 89 64q-109 62 -109 155q0 66 50.5 115t128.5 49zM238 603q-42 0 -67.5 -31t-25.5 -72q0 -50 32.5 -79.5&#xA;t98.5 -62.5q61 48 61 124q0 59 -29.5 90t-69.5 31zM248 20q46 0 76.5 33.5t30.5 89.5q0 50 -39 85.5t-110 71.5q-81 -54 -81 -137q0 -67 35.5 -105t87.5 -38z" /></g><g transform="matrix(.017,-0,0,-.017,34.944,10.862)"><path id="x35" d="M153 550l-26 -186q79 31 111 31q90 0 141.5 -51t51.5 -119q0 -93 -89 -166q-85 -69 -173 -71q-32 0 -61.5 11.5t-41.5 23.5q-18 17 -17 34q2 16 22 33q14 9 26 -1q61 -50 124 -50q60 0 93 43.5t33 104.5q0 69 -41.5 110t-121.5 41q-53 0 -102 -20l38 305h286l6 -8&#xA;l-26 -65h-233z" /></g><g transform="matrix(.017,-0,0,-.017,43.103,10.862)"><path id="x37" d="M447 623l8 -12l-283 -613l-74 -10l-7 11q174 283 297 551h-216q-48 0 -62.5 -12t-33.5 -63h-29q10 60 18 148h382z" /></g>

		
	
</svg>, <svg     style="vertical-align:-0.1638pt;width:66.875px;" id="M4" height="11.375" version="1.1" viewBox="0 0 66.875 11.375" width="66.875"  xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg">
	
		
			<g transform="matrix(.017,-0,0,-.017,.062,11.112)"><use xlink:href="#x1D443"/></g><g transform="matrix(.017,-0,0,-.017,15.582,11.112)"><use xlink:href="#x3D"/></g><g transform="matrix(.017,-0,0,-.017,30.286,11.112)"><use xlink:href="#x30"/></g><g transform="matrix(.017,-0,0,-.017,38.446,11.112)"><use xlink:href="#x2E"/></g><g transform="matrix(.017,-0,0,-.017,42.321,11.112)"><use xlink:href="#x30"/></g><g transform="matrix(.017,-0,0,-.017,50.481,11.112)"><use xlink:href="#x30"/></g><g transform="matrix(.017,-0,0,-.017,58.64,11.112)"><use xlink:href="#x37"/></g>

		
	
</svg>). Total Hammersmith scores also negatively correlated with anterior midbody MD measures (rho <svg     style="vertical-align:-0.1638pt;width:61.3125px;" id="M5" height="11.125" version="1.1" viewBox="0 0 61.3125 11.125" width="61.3125"  xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg">
	
		
			<g transform="matrix(.017,-0,0,-.017,.062,10.862)"><use xlink:href="#x3D"/></g><g transform="matrix(.017,-0,0,-.017,14.749,10.862)"><path id="x2212" d="M535 230h-483v50h483v-50z" /></g><g transform="matrix(.017,-0,0,-.017,24.728,10.862)"><use xlink:href="#x30"/></g><g transform="matrix(.017,-0,0,-.017,32.887,10.862)"><use xlink:href="#x2E"/></g><g transform="matrix(.017,-0,0,-.017,36.763,10.862)"><use xlink:href="#x37"/></g><g transform="matrix(.017,-0,0,-.017,44.922,10.862)"><use xlink:href="#x31"/></g><g transform="matrix(.017,-0,0,-.017,53.082,10.862)"><path id="x34" d="M456 178h-96v-72q0 -51 12.5 -62.5t72.5 -16.5v-27h-256v27q65 5 78 17t13 62v72h-260v28q182 271 300 426h40v-407h96v-47zM280 225v295h-2q-107 -148 -196 -295h198z" /></g>

		
	
</svg>, <svg     style="vertical-align:-0.1638pt;width:66.875px;" id="M6" height="11.375" version="1.1" viewBox="0 0 66.875 11.375" width="66.875"  xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg">
	
		
			<g transform="matrix(.017,-0,0,-.017,.062,11.112)"><use xlink:href="#x1D443"/></g><g transform="matrix(.017,-0,0,-.017,15.582,11.112)"><use xlink:href="#x3D"/></g><g transform="matrix(.017,-0,0,-.017,30.286,11.112)"><use xlink:href="#x30"/></g><g transform="matrix(.017,-0,0,-.017,38.446,11.112)"><use xlink:href="#x2E"/></g><g transform="matrix(.017,-0,0,-.017,42.321,11.112)"><use xlink:href="#x30"/></g><g transform="matrix(.017,-0,0,-.017,50.481,11.112)"><use xlink:href="#x34"/></g><g transform="matrix(.017,-0,0,-.017,58.64,11.112)"><use xlink:href="#x37"/></g>

		
	
</svg>). <i  >Discussion</i>. These results suggest the integrity of corpus callosum axons, particularly anterior midbody axons, is important in mediating neurological functions. Greater callosal maturation was associated with greater motor function. Corpus callosum DTI may prove to be a valuable screening or prognostic marker.

Preethi Mathew

Kerstin Pannek

Pamela Snow

M. Giulia D'Acunto

Andrea Guzzetta

Stephen E. Rose

Paul B. Colditz

Simon Finnigan

Maturation of Corpus Callosum Anterior Midbody Is Associated with Neonatal Motor Function in Eight Preterm-Born Infants

Physical exercise effects on brain health and cognitive performance have been described. Synaptic remodeling in hippocampus induced by physical exercise has been described in animal models, but the underlying mechanisms remain poorly understood. Changes in astrocytes, the glial cells involved in synaptic remodeling, need more characterization. We investigated the effect of moderate treadmill exercise (20&#x2009;min/day) for 4 weeks on some parameters of astrocytic activity in rat hippocampal slices, namely, glial fibrillary acidic protein (GFAP), glutamate uptake and glutamine synthetase (GS) activities, glutathione content, and S100B protein content and secretion, as well as  brain-derived neurotrophic factor (BDNF) levels and glucose uptake activity in this tissue. Results show that moderate treadmill exercise was able to induce a decrease in GFAP content (evaluated by ELISA and immunohistochemistry) and an increase in GS activity. These changes could be mediated by corticosterone, whose levels were elevated in serum. BDNF, another putative mediator, was not altered in hippocampal tissue. Moreover, treadmill exercise caused a decrease in NO content. Our data indicate specific changes in astrocyte markers induced by physical exercise, the importance of studying astrocytes for understanding brain plasticity, as well as reinforce the relevance of physical exercise as a neuroprotective strategy.

Caren Bernardi

Ana Carolina Tramontina

Patr&#xed;cia Nardin

Regina Biasibetti

Ana Paula Costa

Adriana Fernanda Vizueti

Cristiane Batassini

Lucas Silva Tortorelli

Krista Min&#xe9;ia Wartchow

M&#xe1;rcio Ferreira Dutra

Larissa Bobermin

Patr&#xed;cia Sesterheim

Andr&#xe9; Quincozes-Santos

Jaqueline de Souza

Carlos Alberto Gon&#xe7;alves

Treadmill Exercise Induces Hippocampal Astroglial Alterations in Rats

Long-term potentiation (LTP) which has long been considered a cellular model for learning and memory is defined as a lasting enhancement in synaptic transmission efficacy. This cellular mechanism has been demonstrated reliably in the hippocampus and the amygdala&#x2014;two limbic structures implicated in learning and memory. Earlier studies reported on the ability of cortical stimulation of the entorhinal cortex to induce LTP simultaneously in the two sites. However, to retain a stable baseline of comparison with the majority of the LTP literature, it is important to investigate the ability of fiber stimulation such as perforant path activation to induce LTP concurrently in both structures. Therefore, in this paper we report on concurrent LTP in the basolateral amygdala (BLA) and the dentate gyrus (DG) subfield of the hippocampus induced by theta burst stimulation of perforant path fibers in freely behaving Sprague-Dawley rats. Our results indicate that while perforant path-evoked potentials in both sites exhibit similar triphasic waveforms, the latency and amplitude of BLA responses were significantly shorter and smaller than those of DG. In addition, we observed no significant differences in either the peak level or the duration of LTP between DG and BLA.

J. Harry Blaise

Rachel A. Hartman

Stimulation of Perforant Path Fibers Induces LTP Concurrently in Amygdala and Hippocampus in Awake Freely Behaving Rats

About this journal

<p><em>Neural Plasticity</em> is an interdisciplinary journal dedicated to the publication of articles related to all aspects of neural plasticity, with special emphasis on its functional significance as reflected in behavior and in psychopathology.</p>


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<p>Chief Editor, Professor Baudry, is currently University Professor at Western University of Health Sciences in Pomona, CA. His research focuses on understanding the molecular/cellular mechanisms of learning and memory and neurodegeneration.</p>


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Neural Plasticity - Table of contents 2013

title

Neural Plasticity is an interdisciplinary journal dedicated to the publication of articles related to all aspects of neural plasticity, with special emphasis on its functional significance as reflected in behavior and in psychopathology.

Neural Plasticity