Researchers


Dr. Alberto Bacci
Cellular Physiology of Cortical Microcircuits

Group Leader

Tags:

Education and Experiences

December 2005 - Present
Group Leader, European Brain Research Institute (EBRI), Rome, Italy.

May 2003 - December 2005
Life Science Research Associate, Department of Neurology and Neurological Sciences, Stanford University Medical Center, Stanford, CA 94305, USA.

November 1999 - April 2003
Postdoctoral Fellow in Drs David A. Prince and John R. Huguenard laboratory, at the Department of Neurology and Neurological Sciences, Stanford University Medical Center, Stanford, CA 94305, USA.

November 1999
Ph.D. in Experimental Pharmacology and Therapeutics. Department of Medical Pharmacology, University of Milano, Italy


Publications

Marinelli S, Pacioni S, Cannich A, Marsicano G, Bacci A. (2009)
Self-modulation of neocortical glutamatergic neurons by endocannabinoids. Nature Neurosci 12:1488-90

Marinelli S, Pacioni S, Bisogno T, Di Marzo V, Prince DA, Huguenard JR, Bacci A. The endocannabinoid 2-AG is responsible for the slow self inhibition in neocortical interneurons. J Neurosci (2008) 28:13532-13541

Farioli-Vecchioli S, Saraulli D, Costanzi M,  Pacioni S, Cinà I, Aceti M, Micheli L, Bacci A, Cestari V, Tirone F. The timing of differentiation of adult hippocampal neurons is crucial for spatial memory (2008) PLoS Biol. 6:e246

Bacci A., Huguenard JR. (2006) Enhancement of spike timing precision by autaptic transmission in neocortical inhibitory interneurons. Neuron 49:119-30.


Bacci A., Huguenard JR, Prince DA. (2005) Modulation of neocortical interneurons: extrinsic influences and exercises in self-control. Trends in Neurosci. 28:602-611.

Bacci A., Huguenard JR, Prince DA. (2004) Long-lasting self-inhibition of neocortical interneurons mediated by endocannabinoids. Nature 431:312-316.

Bacci A., Rudolph U, Huguenard JR, Prince DA. (2003) Major differences in inhibitory synaptic transmission onto two neocortical interneuron subclasses. J. Neurosci. 23:9664-9674.

Bacci A., Huguenard JR, Prince DA (2003) Functional autaptic neurotransmission in fast-spiking interneurons: a novel form of feedback inhibition in the neocortex. J. Neurosci. 23: 859-66.

Bacci A., Huguenard JR, Prince DA (2002) Differential modulation of synaptic transmission by neuropeptide Y in rat neocortical neurons. Proc. Natl. Acad. Sci. (U.S.A.) 99: 17125-30.

Bacci A., Verderio C, Sancini G, Fesce R, Franceschetti S, Matteoli M (2002) Block of glutamate-glutamine cycle between astrocytes and neurons inhibits epileptiform activity in hippocampus J. Neurophysiol. 88: 2302-10.

Kumar SS, Bacci A., Kharazia V, Huguenard JR. (2002) A developmental switch of AMPA receptor subunits in neocortical pyramidal neurons. J Neurosci. 22:3005-15.

Armano S, Coco S, Bacci A., Pravettoni E, Schenk U, Verderio C, Varoqui H, Erickson JD, Matteoli M. (2002) Localization and functional relevance of system a neutral amino acid transporters in cultured hippocampal neurons. J Biol Chem. 277:10467-73.

Bacci A., Coco S, Pravettoni E, Schenk U, Armano S, Frassoni C, Verderio C, De Camilli P, Matteoli M. (2001) Chronic blockade of glutamate receptors enhances presynaptic release and downregulates the interaction between synaptophysin-synaptobrevin-vesicle-associated membrane protein 2. J Neurosci. 21:6588-96.

Pravettoni E, Bacci A., Coco S, Forbicini P, Matteoli M, Verderio C. (2000) Different localizations and functions of L-type and N-type calcium channels during development of hippocampal neurons. Dev. Biol. 227:581-94.

Verderio C, Coco S, Pravettoni E, Bacci A., Matteoli M. (1999) Synaptogenesis in hippocampal cultures. Cell Mol Life Sci. 55:1448-62.

Verderio C, Bacci A., Coco S, Pravettoni E, Fumagalli G, Matteoli M. (1999) Astrocytes are required for the oscillatory activity in cultured hippocampalneurons. Eur J Neurosci. 11:2793-800.

Verderio C, Coco S, Bacci A., Rossetto O, De Camilli P, Montecucco C, Matteoli M. (1999) Tetanus toxin blocks the exocytosis of synaptic vesicles clustered at synapses but not of synaptic vesicles in isolated axons. J Neurosci. 19:6723-32.

Bacci A., Verderio C, Pravettoni E, Matteoli M. (1999) The role of glial cells in synaptic function. Philos Trans R Soc Lond B Biol Sci. 354:403-9.

Bacci A., Verderio C, Pravettoni E, Matteoli M. (1999) Synaptic and intrinsic mechanisms shape synchronous oscillations in hippocampal neurons in culture. Eur J Neurosci. 11:389-97.

Guatteo E, Franceschetti S, Bacci A., Avanzini G, Wanke E. (1996) A TTX-sensitive conductance underlying burst firing in isolated pyramidal neurons from rat neocortex. Brain Res. 741:1-12.

Guatteo E, Bacci A., Franceschetti S, Avanzini G, Wanke E. (1994) Neurons dissociated from neocortex fire with ´burst´ and ´regular´ trains of spikes. Neurosci Lett. 175:117-20.


Awards

2008
European Research Council (ERC): Starting Grant
 
2007
Member of the European Neuroscience Institute Young Investigator Network 
 
2005
Giovanni Armenise-Harvard Foundation: Career Development Award. 
 
1997
Howard Hughes Medical Institute Scholarship, USA. 
 
1997
Neurobiology Course at the Marine Biological Laboratory, Woods Hole, MA, USA. 
 
1995
Ph.D. Program, University of Milano, Italy


Scientific Collaborations


Group Members

Silvia Marinelli, Frédéric Manseau, Pablo Mendez, Antonio Pazienti, Simone Pacioni

Laboratorio di Fisiologia Cellulare dei Microcircuiti della Corteccia Cerebrale

COMPONENTI DEL GRUPPO


 
Silvia Marinelli | Research Scientist |
s.marinelli@ebri.it

My main research interest is endocannabinoids and their receptors, the TRPV1 and CB1. I am currently focused on neocortical LTS interneurons and their involvement in the endocannabinoid system responsible for the slow self-inhibiton (SSI). In the past I have studied TRPV1-modulation by endocannabinoids in catecholaminergic neurons in sevaral brain areas at Fondazione Santa Lucia, and at University of Sidney Australia I use electrophysiological and pharmacological techniques in acute brain slices and retrograde tracing techniques in vivo.

S. Marinelli, T. Pascucci, G. Bernardi, S. Puglisi-Allegra, and N. B. Mercuri. Activation of TRPV1 in the VTA excites dopaminergic neurons and increases chemical- and noxious-induced dopamine release in the nucleus accumbens. Neuropsycopharmacology (2005) May;30(5):864-70

S.Marinelli, V. Di Marzo, N. Berretta, I. Matias, M. Maccarrone, G. Bernardi and N. B. Mercuri Presynaptic facilitation of glutamatergic synapses to dopaminergic neurons of the rat substantia nigra by endogenous stimulation of vanilloid receptors. J. Neuroscience 23(8):3136-3144 (2003)

S.Marinelli, S.Schnell, C.W.Vaughan W.Wessendorf, M.J.Christie Rostral ventromedial medulla neurons that project to the spinal cord express multiple opioid receptor phenotypes. J. Neuroscience, 22(24): 10847-10855 (2002)

S. Marinelli, C.W. Vaughan, M.J. Christie M. Connor Capsaicin activationof glutamatergic synaptic transmission in the rat locus coeruleus in vitro. J. Physiology 543, pp. 531-540, (2002).


 
Frédéric Manseau | Research Scientist |
f.manseau@ebri.it

 
Pablo Mendez | Research Scientist |
p.mendez@ebri.it

 
Antonio Pazienti | Research Scientist |
a.pazienti@ebri.it
Antonio Pazienti completed physics studies at Rome´s university "La Sapienza" in 2002 with a diploma thesis in theoretical physics. During his PhD A. Pazienti worked in the field of computational neuroscience in Sonja Grün´s lab, both at the Freie University Berlin, Germany and at RIKEN Brain Science Institute, Saitama, Japan. He got his PhD in physics from the University of Potsdam, Germany in 2008. [full CV] 

Before joining Dr. Bacci´s laboratory at EBRI, where I combine electrophysiology and computer simulation, I worked in the field of computational neuroscience, and my work was mainly focussed on how to improve methods of analysis and interpretation of neurophysiological data. This was achieved by employing theoretically rigorous statistical and computational tools, and working in close contact with electrophysiologists.

In the following I give an overview of my past projects.

Introduction. In order to answer the challenging question of how the brain computes, a fundamental methodological step is constituted by recording large sets of single neurons in parallel. Techniques that allow this task, such as arrays of extracellular electrodes, have become available in the last couple of decades, and are meanwhile widely employed. They allow the simultaneous recording of tens to hundreds of neurons. Such technological improvements yet need to be accompanied by analogous advancements in the pre-processing of the large volumes of acquired data and in data analysis techniques.
Major issues in the analysis of correlation between multiple parallel recordings involve the correct isolation and identification of individual neurons (a procedure referred to as spike sorting). Spike sorting is a fundamental step in the treatment of extracellular electrophysiological data, however it is subject to errors whose effects are poorly studied.
Another important issue is the availability of distributions for assessing statistical significance. Making assumptions on the statistics of spike trains requires long recordings and repeated measurements, but neurophysiological data often do not fulfill these requirements. Algorithms are used for creating surrogate distributions by selectively destroying some features of the data while preserving their main structure. However the effectiveness of algorithms in generating surrogates yet needs to be ultimately established.


Project "Effect of spike sorting errors on synchrony analysis"

Pazienti fig1 (Bacci) (sml)This project involved the estimation of the severity of the impact of poor spike sorting onto synchrony analysis aimed to detect assembly activity from extracellular, multi-electrode recordings. My results show that coincidence patterns of multiple parallel spike trains are severely affected by spike sorting. Synchronization analyses underestimate in most cases the underlying correlation due to spike sorting errors. This holds true even when only false positive errors --i.e. spikes assigned to a neuron although they belong to other neurons or they are noise artifacts-- affect the data. However, false negative errors --i.e. erroneously un- or mis-classified spikes-- have a more severe impact on the significance than false positive errors [1].
This result suggests that sorting strategies characterized by classifying only ´´good´´ spikes (conservative strategies) are prone to more inaccurate estimations than ´´tolerant´´ strategies.

 

Project "Creating surrogate data by spike dithering"

SpikeTrains CMYK (Bacci) (sml)In another project done in collaboration with Prof. Maldonado of the university of Santiago, Chile I investigated the effectiveness of methods for creating surrogate distributions for statistical significance. These methods destroy correlations in the data by displacing coincident spikes around their original position (referred to as spike dithering). I contrasted different strategies of spike dithering (namely dithering 1 or both neurons) against two established methods of counting coincident patterns: by partitioning the temporal axis in disjunct bins (Disjunct Binning), and by integrating the coincidence count over multiple relative shifts of the spike trains (Multiple Shift).
In my results I provide analytical expressions of the probability of coincidence detection after dithering. These lead to establish the real effectiveness of  the dithering methods and allowed us to predict the time scale with which neuronal signals from electrophysiological   experiments syonize themselves (see figure), presumably in order to process and transmit information [2,3].

Selected publications:
[1] Pazienti A and Grün S, Robustness of the Significance of Spike Synchrony with respect to Sorting Errors, J Comput Neurosci. 2006 Dec 21(3):329-42 [PDF]

[2] Pazienti A, Diesmann M, Grün S, Bounds of the ability to destroy precise coincidences by spike dithering, Advances in Brain, Vision, and Artificial Intelligence, Lecture Notes in Computer Science. 2007 Springer Berlin / Heidelberg, chap. 41, 428-437 [PDF]

[3] Pazienti A, Maldonado P, Diesmann M and Grün S, The effectiveness of systematic spike dithering depends on the precision of cortical synchronization, Brain Research, Brain and Vision, 2008, 1225, 39-46 [PDF]
 
 
Simone Pacioni | PhD student |
s.pacioni@ebri.it