Synaptic Activity

LTP | CSD

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Example 1: Long Term Potentiation in Acute Hippocampus

*Simply place the slice on the MED probe and you are ready to record! (No need to manipulate grass electrodees).
*No need for a special shielded environment. Conduct your experiment everyday under stable low-noise levels.
*Look for the best stimulation point easily by using the control panel in front of the amplifier.
*Conduct your experimetns and get on-line analysis using MED64 Mobius software.

 
Top left: Micrograph of a hippocampal slice obtained from a C57BL6 mouse placed on MED-P515A probe (150 m m inter-polar distance) and centered on apical region of field CA1. Population EPSPs (pEPSPs) are elicited by a single pulse stimulation to the electrode marked in blue and responses are recorded at the other 63 electrodes.

Bottom: The time course of the slope measured at the electrode marked in red taken from before (green) and after (red) a theta burst stimuation. 

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Example 2: Longevity of LTP in Cultured Hippocampal Slices

A.Hippocampal slices cultured on the MED probe (150 µm inter-electrode spacing)

B. Field EPSPs evoked by Schaffer/Commisural stimulation were recorded in field CA1 before and after tetanic stimulation.

C.Summary graph showing the stability of LTP over several days. The amplitude of the fEPSP (calculated as a percentage of averaged baseline values; means ±S.E.M., n=8) , is shown for the control and potentiated pathways. Arrows indicate the time of tetanus stimulation.

D.LTP amplitude was averaged over a 10 min period at 1h, 24h, and 48h after tetanus stimulation, and was expressed as percentage of baseline values.

Shimono K et al., Neural Plasticity 2002, 9(4) 249-254

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Example 1: Continuous Two-Dimensional Current Source Density Analysis Of An Evoked Response

A. Placement of an 8 x 8 MED64 electrode array, with an interelectrode spacing of 100 µm, centered in the apical dendritic field of CA1 in a rat hippocampal slice.

B. Evoked field EPSP (black) and field EPSC (red) are elicited by a single pulse to the electrode marked in red and measured at the electrode in blue

C. The computed continuous two-dimensional current source density plots across all electrodes at specified time points. After an initial response due to the fiber volley, a current sink spreads rapidly through the stratum radiatum zone of field CA1. The sink intensifies and expands over roughly 5 ms and then fades, disappearing at about 20 ms. The apical sink is accompanied by a field of current source appearing in both the basal dendrites and the stratum lacunosum/moleculare.

K. Shimono et al. Brain Res., 2002, 950(1-2):279-287

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Example 2: Current Source Density of Beta Rhythms

These sequences were obtained from hippocampal slices after spontaneous activity was induced by application of 50uM carbachol and recorded using a MED probe with electrode spacings of 450um [see Shimono et. al. (2000) for details].

Two sequences are available:

Note that the outlines indicate the location of the cell body layers of dentate gyrus and of CA3/CA1, time units are in ms, sources are yellow, sinks are blue and the dot in the circle indicates cycle phase.