Controlling synaptic input patterns in vitro by dynamic photo stimulation.
Recent experimental and theoretical work indicates that both the intensity and the temporal structure of synaptic activity strongly modulate the integrative properties of single neurons in the intact brain. However, studying these effects experimentally is complicated by the fact that, in experimental systems, network activity is either absent, as in the acute slice preparation, or difficult to monitor and to control, as in in vivo recordings. Here, we present a new implementation of neurotransmitter uncaging in acute brain slices that uses functional projections to generate tightly controlled, spatio-temporally structured synaptic input patterns in individual neurons. For that, a set of presynaptic neurons is activated in a precisely timed sequence through focal photolytic release of caged glutamate with the help of a fast laser scanning system. Integration of synaptic inputs can be studied in postsynaptic neurons that are not directly stimulated with the laser, but receive input from the targeted neurons through intact axonal projections. Our new approach of dynamic photo stimulation employs functional synapses, accounts for their spatial distribution on the dendrites, and thus allows study of the integrative properties of single neurons with physiologically realistic input. Data obtained with our new technique suggest that, not only the neuronal spike generator, but also synaptic transmission and dendritic integration in neocortical pyramidal cells, can be highly reliable.
Boucsein
Clemens
C
Neurobiology and Biophysics, Institute of Biology III, Albert-Ludwigs-University, Freiburg, Germany. clemens.boucsein@biologie.uni-freiburg.de
Nawrot
Martin
M
Rotter
Stefan
S
Aertsen
Ad
A
Heck
Detlef
D
D000200:Action Potentials / Q000502:physiology; D000818:Animals; D004558:Electric Stimulation / Q000295:instrumentation; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects; D066298:In Vitro Techniques; D008959:Models, Neurological; D009431:Neural Conduction; D009433:Neural Inhibition; D017711:Nonlinear Dynamics; D018408:Patch-Clamp Techniques / Q000379:methods; D010775:Photic Stimulation / Q000295:instrumentation*; D017966:Pyramidal Cells / Q000502:physiology*; D011930:Reaction Time / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects; D013003:Somatosensory Cortex / Q000166:cytology*; D013569:Synapses / Q000502:physiology*; D009435:Synaptic Transmission / Q000502:physiology*; D013779:Tetrodotoxin / Q000494:pharmacology; D013997:Time Factors
D013779:Tetrodotoxin