Neuroscience 2005 Abstract
| Presentation Number: | 179.3 |
|---|---|
| Abstract Title: | Integration of distributed granule cell synaptic inputs by Purkinje cell dendrites. |
| Authors: |
O'Connor, D. H.*1,3
; Sarkisov, D. V.2,3
; Shoham, S.1,3
; Wang, S. S-. H.1,3
1Molecular Biology, Princeton Univ., Princeton, NJ 2Physics, Princeton Univ., Princeton, NJ 3Program in Neuroscience, Princeton Univ., Princeton, NJ |
| Primary Theme and Topics |
Sensory and Motor Systems - Cerebellum -- Cortex and nuclei |
| Secondary Theme and Topics | Techniques in Neuroscience<br />- Physiological Methods |
| Session: |
179. Cerebellum, Physiology and Models Poster |
| Presentation Time: | Sunday, November 13, 2005 10:00 AM-11:00 AM |
| Location: | Washington Convention Center - Hall A-C, Board # CC17 |
| Keywords: | optical, uncaging, two-photon, tomatotopic |
We used an acousto-optic deflector UV uncaging system (Shoham et al., SFN 2004, 737.19) to stimulate multiple sites within the granule cell layer of sagittal slices from rat (P18-20) cerebellum. Responses were recorded using whole-cell patch clamp recordings made from Purkinje neurons. Locations were activated by uncaging 170 μM MNI-glutamate within 0.5 ms at a 3 x 3 array of points spaced at 1.3-2.0 μm intervals. Responding locations were identified by measuring the change in a post-uncaging time window of 70-90 ms over many sweeps, and defining a t-score as the mean divided by the SEM. Locations with t > 2 were scored as responding. Responses were reduced somewhat by APV (200-400 μM) and were completely eliminated by subsequent addition of lidocaine (500 μM), consistent with the hypothesis that photolyzed glutamate triggered synaptic responses via activation of granule cells and not by direct activation of Purkinje cells, which have AMPA but not NMDA receptors.
Averaged responses had short onset delays from the first uncaging flash (latency 12.6 ± 10.2 ms, mean ± SD; n=18 locations in 4 Purkinje cells) and had peak amplitudes of 1-54 pA (mean 19 pA, 25%-75% interquartile range 7 to 28 pA). These response amplitudes are comparable to EPSC measurements made from unitary granule cell-Purkinje cell pairs (Barbour, Neuron 1993 11:759). At the same time, multiple rising phases could often be seen in individual responses, indicating the likelihood of burst firing and consistent with the firing properties of granule cells. To study synaptic integration we activated multiple granule cells at once in rapid succession (inter-location interval of <0.5 ms to 200 ms). At the shortest inter-location intervals granule cell-Purkinje cell responses typically summated to produce a burst of simple spikes in the Purkinje cell. We are now investigating the properties of granule cell-Purkinje cell synaptic integration under dense and distributed activation patterns.
Averaged responses had short onset delays from the first uncaging flash (latency 12.6 ± 10.2 ms, mean ± SD; n=18 locations in 4 Purkinje cells) and had peak amplitudes of 1-54 pA (mean 19 pA, 25%-75% interquartile range 7 to 28 pA). These response amplitudes are comparable to EPSC measurements made from unitary granule cell-Purkinje cell pairs (Barbour, Neuron 1993 11:759). At the same time, multiple rising phases could often be seen in individual responses, indicating the likelihood of burst firing and consistent with the firing properties of granule cells. To study synaptic integration we activated multiple granule cells at once in rapid succession (inter-location interval of <0.5 ms to 200 ms). At the shortest inter-location intervals granule cell-Purkinje cell responses typically summated to produce a burst of simple spikes in the Purkinje cell. We are now investigating the properties of granule cell-Purkinje cell synaptic integration under dense and distributed activation patterns.
Supported by NSF, NIH, Keck Foundation.
Sample Citation:
[Authors]. [Abstract Title]. Program No. XXX.XX. 2005 Neuroscience Meeting Planner. Washington, DC: Society for Neuroscience, 2005. Online.
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