BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Talks.cam//talks.cam.ac.uk//
X-WR-CALNAME:Talks.cam
BEGIN:VEVENT
SUMMARY:How developmental origin determines microcircuit function in the h
 ippocampus.  - Rosa Cossart Institute for Neuroscence\, Montpellier
DTSTART:20150119T163000Z
DTEND:20150119T180000Z
UID:TALK56604@talks.cam.ac.uk
CONTACT:P.H. Marchington
DESCRIPTION:Most adult cortical dynamics are dominated by a minority of hi
 ghly active neurons distributed within a silent neuronal mass. If cortical
  spikes are sparse\, spiking of single distinct neurons can impact on netw
 ork dynamics and drive an animal’s behavior.  It is thus essential to un
 derstand whether this active and powerful minority is predetermined and if
  true to uncover the rules by which it is set during development. In this 
 talk\, I will present data supporting the possibility that birthdate is a 
 critical determinant of neuronal network function into adulthood.   More s
 pecifically\, we reason that neurons that are born the earliest are primed
  to participate into adult network dynamics. This hypothesis is considerab
 ly fed by our past work aiming at understanding how cortical networks func
 tion and assemble during development. Hence\, we have shown that an early 
 birthdate: (1) specifies the specialization of GABA neurons with a hub fun
 ction\, that orchestrate perinatal network dynamics in the mouse hippocamp
 us (Bonifazi et al. Science 2009) and develop into long-range projecting G
 ABA neurons into adulthood (Picardo et al. Neuron 2011)\; (2) delineates a
  subtype of CA3 glutamate neuron with a “pacemaker” function in the ab
 sence of fast GABAergic transmission (Marissal et al. Nature Comm. 2012). 
  I will first briefly present this set of published data.\nTo test the hyp
 othesis that early born cells are primed to be recruited in the active min
 ority of neurons in the adult hippocampus\, we needed to probe microcircui
 t function in vivo\, where the extensive and long-range connectivity of th
 ese cells is preserved. I will show how we have translated from the in vit
 ro to the in vivo situation\, our multidisciplinary method to investigate 
 structure-dynamics relationship in cortical networks. Using this approach\
 , I will last present unpublished data showing that\, in the absence of ex
 ternal landmarks\, distance is encoded within the adult hippocampus in rec
 urrent and self-circumscribed sequences of neuronal activation (Villette a
 nd Malvache et al.\, in revision).  These sequences integrate traveled dis
 tance and link sequential body movements to an internal distance template.
  These distance sequences are an excellent theoretical and experimental mo
 del to probe the involvement of early born cells in sparse dynamics becaus
 e they repeatedly involve small subsets of neurons and because they almost
  represent default hippocampal dynamics in the absence of any external dri
 ve\, which is probably more likely to be influenced by developmental progr
 ams. In the future\, we will examine the recruitment of early born neurons
  in this sparse hippocampal network dynamics pattern.\n
LOCATION:The Hodgkin Huxley Seminar Room\, Department of Physiology Develo
 pment and Neuroscience
END:VEVENT
END:VCALENDAR