Abstracts of the 13th Annual Meeting of Israel Society for Neuroscience

2005 Neural Plasticity  
The octopus arm lacks agy rigid skeleton and has virtually .an_ intimte n.u.mb"er of degrees of freedom (.DOFs): .Movements oI the octopus arm are studied to understand the motor control of this hyper-redundant system. Previous studies showed that the octopus uses stereotypic reaching move.me_n.ts which .reduce the nqm.be.r of.control parameters to qnly 3 _(,on.e tor tte velocity 9t the tend point propagation ancl two tor the orientation oI.the proximalpart oi-the ._art0), We compar&l movements
more » ... ot a regenerative arm (half the size of normal arms) to those of normal arms in simultaneous reachine movements (both arms reach at the same time, SMs) and" individual reaching movements (.the arms reach independently, IMs). For IM_s, the distance th.at the bend .point moved and the time or movement tor the regenerative arm was half of those of the normal arms. The t.angential velocity profiles had a stereotvlic bell shape car.acterizatio.n...St .mu!ati.gns of I.Ms b.y adynamc, model ot the arms. yielded similar results (t command was a constant velocity wave of muscle activation that took half the time to travel along the am for the smaller arm)..In qgntrast to. IMs, no sigrp,ficant differences were found in the_ distance that the bend point moved and in the time oi reaching between the regenerative arm to the normal arms in SMs. The time and the distance of the reaching movements of the regenerative arm were significantly larger in SMs than in IMs. The standard deviatmn of the maximal velocity of both arm .types vas smaller in .the S.Ms than in the IMs. Tangential velocity.profiles didn't hav.e the bell sh.ape characterization in SMs. Qur.hypothesis is that.in SMs there is one motor command that coordinates the muscle activation wave which propels the bend. School, Hebrew Uhiversity, Jerusalem; Recent advances in neuroscience have led an increasing number of gene targets for treatment of brain tumors ar degenerative CNS diseases. A new and promising therapeutic approach has evolved based on antisense molecules. These are small strands of DNA (oligodeoxynucleotides, ODN) designed to bind to an mRNA tgget, thus inhibiting transcription of encoded protein. The advantage of antisence based treatment is higher selectivity towards a desired target. Polyamide the effects of museimol in the IL or BLA, suggest differential involvement of these structures in lo0.gz-term extinction of fear memory. We propose that consotiation of extinction of fear may .dependent on both the amgd.ala and I..L and concurrently the information is. turter consolilated and stored m the IL. Understanding the interaction between the amygdala and the prefrontal cortex in extinction of fearful experiences is of major interest, since these brain .regions are closely related to the persistence of mala_dalStive fear seen in anxie disorders such as post-traumatic stress disorder (PTSD) and phobia. A balanced network leads to contradictory .constraints on memory .models, as exemplified in previous work on accommodation Of s)aafire cfiains. Here we show that these constraints can be overcome by introducing a shadow' inhibitory pattern for each excitatory pattern of the model. This is ihterpreted as a double-balance principle, whereby there exists both global balance between average excitat .c.o" and inhibitory culrents and local balance between the currents carrying coherent activity at an_3, given time frame. This principle can be applied to networks With Hebbian cell assexfiblies, leading to a high capacity of the. associative me. The. number of LLLLsible patterns is limited, by a eombixiatorial constraint that turns out to be P=0.O6N within the specific model that we employ. This limit is reached by flap Hebbian cell assembly netwk. To the best of our kflowl.edge this .is the first time that such high memory capacities are demonstrated in the asynchronous state ofmodels of spiking neurons. Autoimmune T cells play a role in short-and long-term plasticity Considering the previously observed role of mature T cells in neuronal survival and repair, we h)othesized that a similar function can be a,ttn'buted to suizh T ceils in the context of neural plastic.ity. We examined this h,vp.o.thesis in_ the dentate gyrus (DG; it-vivo) and in stratum'rdiatum the CA1 regain (in-vitro) of transgenic mice e_ongenie to wild-type (WT) leading to the plienotype of absence .of mature T cells (nude mice). In-vivo, we found that the rca,'i to afferent stimulation, had the se fEPSP p0putatibn ike (PS) size. in the nude and WT control mice. In addition, the nude mice showed enhanced paired-the consistent clinical observation of heterotopic ossification and enhanced fracture healing in patients with tra.umatic brain i.njur.-. 5) Stress and depression in humans and experimental ariimats ar.e. associat&l with signic.ant decreases in bone mass attributable to activation el the and.pert!aps other., non-svmoathetic processes. It aopears that e cen.tral control of bone remodeling is medial,dd by multiple pathways. The oro-inflamm_atory eytokine IL-I. acting via the hyl?othalamie IL-I reeel3tor type (IL-1RIy, activates patlaways associated with the restrain, of bone formation such as the hypo.tlglamo pituitary-adrenocortical (HPA) axis and the sympathetic nervous system. In addition, IL-1 has been imphcafed as a mediator or the bone loss induced by sex hormone depletion. To address more specifically the s[eletal regulatory role of central IL-1R1 kignalmg, we ch .aracterized Oe bone phenot3q3e of young IL-'IRI-/mice and mice with astroeyte-targeted oyere.xpression, of..the human IL-1 receptor antagomst, under the control orthe murine glial fibrillary acidic protein promoter (IL-lraTG). lhe .genetically mafiipulated mice showed normal body .w.eiglat ap.d food consumption. Although a previous histomorolaometric study reoorted a normal bone mass. in the IL-1R1-/mice, a pr'esedt micro-comEuted tompgr,aphiq analxsis demonstrated i.mpaired femorhl e.lqngation and radial growth in these anifaals as well as in th IL-IraTG mice. Moreover, the trabecular bone densi.ty in the distal femoral metaphysis and lumbar vertebrae iia both mutant mouse lines was markedly lower as compared to their WT controls. Similar decreases were also seen in the trabeeular thickness, number and connectivity. The orocess lg to the low bbne mass (LBM) p.heno in the IL-lraTG nice ".revolves l.gh turnover bon8 loss, artehz_. by doubling the osteoclast number with substantially smaller increases in osteoblast number and bone fohnation rate. The mechanism involved in the increased bone formation was not related to gonadal dysfunction, as testosterone levels .in the IL-IraTG inice were markedly higher compm'ed to the WT.eontrols. These dma demonstrate a L.B_M. ph.eno.type resulting from the absence of central IL-1RI sig.almg. Whereas previously reported studies suggest a role f6r skel.et,al IE-.IR1 signalirik in bone loss th present fmdin.gs implicate the central ]L-IRI sigrling as a positive regulator of bone mass accrual. Our recent studies have provides evidence whereby activation/regul..ation of protein kinase C (PKC) association -ith Bcl-2 protein family promotes neuronal survival by rasagiline (N-propar.gyl-(IR)-aminoindan), and in relation to its propargylmbiety. In the prent study, we finer investigated fl3e neurorescue effects of Npropargylamine m a progressive neuronal death, induced by long term (3 _days) serum deprivation in SH-SY5Y neui'oblastoma cells. N-propargylamine (0.1-10 mM) dosedependently reduced the levels of the early apoptosisassociated phosphprylation protein, H2A-X (ser-139), as well as decreased the cleavage of easpase-3 and its substrate poly ADP ribose polyn]erase (PAP,P). Long-term serum wthdrawal significantly__down-regulated the antiapoptotic protein, Bel-2, as well as UP regulated the proapoptotic protein, Bax. These effects were markedly reversed in a dose-dependent manner by N-propargylamine. Furthermore, it reduced the levels 6f the pro-apoptotie proteins, Bad and Bim. Using real-time RT-PCR, ve show that N-propgylamine elevated Bcl-2 and reduced Bax gene expression. In addition, serum d_ep.rivation induced increase in protein levels of holo-APP, in consistence with Israel Science Foundaiion and the US-Israel B-Natonal Science Foundaaon. Quantitative analysis of Parvalbumin-and Calbindin-D28Kcontaining neurens in timbic brshr a'uctur and the SSC of Octodon degus after repeated early life stress eker K.,_ Kindler J., Helmeke C. and Braun K. logy/DevelopmentaI Neurobology, Otto von Caiericke Uhiversity, 391t8 Magdeburg, Germany;, Early adverse .experience results in both p.17ysical and osvc'laolocal alterations. Previo.s results in .tlie ._mmapettafle rat (Oetodon de,ms) pointed out. that early life stress leads to a variety ot" riaorphologieal ch.anges .inctu.dirtg region-specific c.lianges of spine densitie.s..Are .these. etianges of exei.tat.ory i_np accompanied .bY alterea GAl3"Aergic modulation? To find agsw.e.rs to ques".tign we .analgzed the t of e_ar.ly life stress on the dey.elop.m...ent of inhitory GABArgic n in the rodent hippocampus, amygdala, pirif-orm cortex and the somatose.mory cortex. The sfressed de,us showed s.ig_ificantlv lower densities of..Parvalburnin-.aLad. Cdbindin-D28k-immunoreactive .{.-Jr) neurons in this hippoeampal su.b,gion. Accordingl.y,. the de.cTeased excitatory .'.input (lor,ver spine densi-ti) in the dentate granule cells .al?.s to "be eom__pegsaft_ by decrease.A fiumbers, of intiibitory neurons. Iri the CAI region, incr e.xcitat.ory input (en.aneed soine densities) apl.ars neither to be compensated nor ampfified by alterefl... nuinbers of GABAergic intemeurons. thus, an overatt enhanced neuronal ility codd be lar. The stress-induced neuronal a_daion in the basolateral .amygdala again differs fr6m that observed in the_ hippo..ampal formation. Increased cell densities ot Parvalburn-and Calbindin-D28k-ir nemons were detectable in the basolateral .agaygdala of early stressed de,as, whereas in the central a..ydaloid nucleus no differ6nces were found. Aecordihg-ly, the ..df, er. eased excitato.rx, input (dee.reused .sine disities) which was r.etx3rted for the lateral amyg .dala appears to be even more d6wnregulated by incr nu/nbers of GABAergic interneurons, frorri which an overall d_ampeninofneuronal excitability, could be ex.pcyte. d...Thdse s[ress-induc.ed changes 6f GABAergic ediated .changes appear to be more or less specific "for some limbic regmns, since in the piriform co.rex and in the somatosensory cortex no quantitative etmnges were detectable.
doi:10.1155/np.2005.1 pmid:15940829 pmcid:PMC2565472 fatcat:6yiorqangzffpo5b3mdytg5xhy