From connelly.bill from gmail.com Sun Sep 13 22:08:29 2009 From: connelly.bill from gmail.com (Bill) Date: Mon Sep 14 10:25:37 2009 Subject: [Neuroscience] Gamma Oscillations Message-ID: <0b46d003-8874-4191-8f8b-a28387d8739b@u36g2000prn.googlegroups.com> Hi, Has anyone ever read a paper where someone has tried to estimuate the size of the depolarizing current that interneurons recieve during gamma oscillations ? (in vivo neocortex preferabley, but I'll take anything) Thanks. From thome.alex from gmail.com Mon Sep 14 23:01:15 2009 From: thome.alex from gmail.com (=?ISO-8859-1?Q?Alex_Thom=E9?=) Date: Tue Sep 15 09:50:59 2009 Subject: [Neuroscience] Re: Neur-sci Digest, Vol 52, Issue 1 In-Reply-To: <200909141706.n8EH6vp09840@net.bio.net> References: <200909141706.n8EH6vp09840@net.bio.net> Message-ID: I think this might be along the lines of what you are looking for. By Peter Jonas's group: Fast synaptic inhibition promotes synchronized gamma oscillations in hippocampal interneuron network. As well as this one from Buzsaki's group: Gamma frequency oscillation in the hippocampus: intracellular analysis in vivo. Not quite necortex, but that should help. Alex Thome ________________________________ Graduate Student/Research Assistant McKnight Brain Institute & ARL Neural Systems Memory and Aging M: (520) 891-2936 http://embi.nsma.arizona.edu Not knowing is true knowledge. Presuming to know is a disease. First realize that you are sick. Then you can move towards health. - Lao Tze On Mon, Sep 14, 2009 at 10:06 AM, wrote: > Send Neur-sci mailing list submissions to > neur-sci@net.bio.net > > To subscribe or unsubscribe via the World Wide Web, visit > http://www.bio.net/biomail/listinfo/neur-sci > or, via email, send a message with subject or body 'help' to > neur-sci-request@net.bio.net > > You can reach the person managing the list at > neur-sci-owner@net.bio.net > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of Neur-sci digest..." > > > Today's Topics: > > 1. Gamma Oscillations (Bill) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Sun, 13 Sep 2009 20:08:29 -0700 (PDT) > From: Bill > Subject: [Neuroscience] Gamma Oscillations > To: neur-sci@net.bio.net > Message-ID: > <0b46d003-8874-4191-8f8b-a28387d8739b@u36g2000prn.googlegroups.com> > Content-Type: text/plain; charset=ISO-8859-1 > > Hi, > > Has anyone ever read a paper where someone has tried to estimuate the > size of the depolarizing current that interneurons recieve during > gamma oscillations ? (in vivo neocortex preferabley, but I'll take > anything) > > Thanks. > > > ------------------------------ > > _______________________________________________ > Neur-sci mailing list > Neur-sci@net.bio.net > http://www.bio.net/biomail/listinfo/neur-sci > > End of Neur-sci Digest, Vol 52, Issue 1 > *************************************** > From kirsch from bccn.uni-freiburg.de Thu Sep 17 04:57:18 2009 From: kirsch from bccn.uni-freiburg.de (Janina Kirsch) Date: Thu Sep 17 10:04:57 2009 Subject: [Neuroscience] Postdoc-Position in Biomicrotechnology at the University of Freiburg, Germany Message-ID: <8F40CFF8B3BC4EB3AC162FE0A4E1B5E9@janina> Development of an electrophysiological in vitro neurotoxicology assay Project Description: In a new project that started september '09 we evaluate the activity patterns in neuronal networks in vitro to assess developmental neurotoxicity (DNT) in long-term multi-electrode electrophysiological recordings. The result should contribute to the development of pharmacological safety tests that would reduce the number of animals needed for DNT testing of industrial chemicals. Requirements: A PhD or doctoral degree in natural sciences is required. The candidate should have extensive experience with cell cultures and ideally also with electrophysiological recordings and their analysis. Knowledge on pharmacological testing would be a plus. Job offer: You would work in an interdisciplinary and international group interested in the properties of neuronal networks and their pathologies. The group is located at the IMTEK, an institute of the technical faculty, and is well embedded in the Bernstein Center for Computational Neuroscience and the Bernstein Focus Neurotechnology in Freiburg. The position is limited to 2 years. The salary is based on TV-L E13 (40.700-47.200 EUR depending on relevant work experience). Contact: Prof. Dr. Ulrich Egert Faculty of Engineering, Albert-Ludwig University of Freiburg Biomicrotechnology , Department of Microsystems Engineering Georges-Koehler-Allee 102 79110 Freiburg Germany Phone: +49 761 203 7524 Fax: +49 321210 34 429 E-mail -- Dr. Janina Kirsch -- Coordinator for the Teaching & Training Programs Bernstein Center Freiburg Albert-Ludwig University of Freiburg Hansastr. 9a D - 79104 Freiburg Germany Phone: +49 (0) 761 203-9575 Fax: +49 (0) 761 203-9559 Email: kirsch @bcf.uni-freiburg.de Web: www.bcf.uni-freiburg.de From kirsch from bccn.uni-freiburg.de Mon Sep 21 08:55:05 2009 From: kirsch from bccn.uni-freiburg.de (Janina Kirsch) Date: Mon Sep 21 10:04:06 2009 Subject: [Neuroscience] Position for a Junior Scientist (Research Associate) in Neurophysiology, University of Freiburg Message-ID: <6EA2180A5AB348D6910C8FF3D27C86F2@janina> % apologies for multiple postings % Junior Scientist Position (Research Associate) at the Laboratory for Biomicrotechnology, Dept. of Microsystems Engineering, Faculty of Engineering University of Freiburg, Freiburg The Laboratory for Biomicrotechnology ( Prof. Ulrich Egert) offers a junior scientist position ( A13, up to 4 years) for a biologist with expertise on electrophysiology, cell culture of neuronal networks, neurophysiology in acute brain slices and/or Ca-imaging. We are interested in the mechanisms and structures underlying the activity dynamics in neuronal networks and the processing of neuronal activity within the network. In joint projects with computational neuroscientists we investigate how the biological neuronal networks process incoming stimuli, what determines intrinsic activity, how pathological dynamics arise and how to contain them. To address these questions we use acute brain slices, cell cultures and animal models with a variety of techniques. A central technology is extracellular recording the neuronal activity with microelectrode arrays to analyze the spatio-temporal structure of activity. Recordings with these arrays are combined with paired intracellular recordings, calcium imaging, microstimulation and advanced data analyses. New technical and analysis tools are developed as needed in collaborations with microsystems engineers. This work is embedded in the Bernstein Center for Computational Neuroscience Freiburg (BCCN Freiburg) and the new Bernstein Focus Neurotechnology - Freiburg/Tuebingen. The successful candidate is expected to contribute to the teaching and training program of these iniatives. Candidates should have outstanding academic records and an interest in translational neuroscience and neurotechnology. The position is open immediately until filled. For further information, please contact Prof. Ulrich Egert (Head of laboratory) or Dr. Janina Kirsch (Coordinator for the Teaching & Training Programs). -- Dr. Janina Kirsch -- Coordinator for the Teaching & Training Programs Bernstein Center Freiburg Albert-Ludwig University of Freiburg Hansastr. 9a D - 79104 Freiburg Germany Phone: +49 (0) 761 203-9575 Fax: +49 (0) 761 203-9559 Email: kirsch @bcf.uni-freiburg.de Web: www.bcf.uni-freiburg.de From jonesmat from physiology.wisc.edu Mon Sep 28 14:16:09 2009 From: jonesmat from physiology.wisc.edu (jonesmat) Date: Mon Sep 28 16:03:41 2009 Subject: [Neuroscience] Re: How do you deal with equations when the denominator tends to 0? References: <418a025b-8b78-4ed8-a14a-ca4bcc45922b@a39g2000pre.googlegroups.com> Message-ID: On Aug 18, 9:38?pm, Bill wrote: > This is more of a maths question than a neuroscience question, but > I've come across it twice when dealing with neuroscience problems > > 1) I was trying to solve the Goldman Hodgkin Katz field equation, > which I shan't type out here in full, but it has a denonimator term of > 1-e^(-z.V.F/RT) so when V=0, the denominator is 0. Obviously, I could > calculate the value fractionally above 0, and fractionally below 0, > and average the result to get the value for 0; but I was wondering if > there was a smarter way > > 2) Now here is the real problem. I've got some voltage ramp data, I > wanted to convert the current trace to a conductance trace using G = I/ > (Vm-Ve). However as Vm approaches Ve the trace goes crazy (obviously > again, at Vm=Ve I couldn't calculate G, but even as Vm-Ve gets very > small, presumabley the noise of the trace is amplified, so you have a > rectangular hyperbola overlaid on a bolztman style curve). Is there > anything I can do about this? (and filtering doesn't work). Bill, How about a Taylor expansion of the function near zero, then only take the first few terms of the polynomial, which won't be crazy yet. However this will give no better results than just averaging over the nearby points, so realistically you should probably just do that! Matt From hind2007 from gmail.com Wed Sep 30 10:40:05 2009 From: hind2007 from gmail.com (Hind) Date: Wed Sep 30 13:14:37 2009 Subject: [Neuroscience] Smooth in mathematica program Message-ID: <1f60427d-e96b-438b-978d-9c66a3977f5f@c28g2000yqd.googlegroups.com> Hi, I plot my function in 3D, for example: Plot3D[300 + (Io s c Exp[(-s) x]) Sin[a t], {t, 0, 4?10^-12}, {x, 0, 1.5?10^-6}, PlotPoints -> 30]) out = SurfaceGraphics.................. I obtained the figure(curve), it look OK, but, it need to be smoothed (oscillation should be avoided). Now my quastion How i can make smooth for this figure in Mathematica program? Thank you Hind From connelly.bill from gmail.com Wed Sep 30 19:51:49 2009 From: connelly.bill from gmail.com (Bill) Date: Wed Sep 30 22:05:13 2009 Subject: [Neuroscience] Neuronal Soma size vs the size of the animal Message-ID: <8bcc4ca7-9e59-4c91-abb6-6f9089983fa7@a39g2000pre.googlegroups.com> Has anyone seen any information on the size of neuronal somata relative to the size of the animal? I read the other day that drosophila have very small somata (but of course, invertebrate neurons are structured quite differently). I could imagine a corticospinal neuron having a bigger soma in a big animal, because it has further to project, more surface area and hence needs more protein synthesis, but what about local neurons? Or granule cells? Thanks.