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 amplifier.
*Conduct your experimetns and get on-line analysis using MED64 Mobius software.

A. 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. Field EPSPs are elicited by a single pulse to the electrode marked in blue and measured at the other 63 electrodes.

B. Field EPSP measured at the electrode marked in red before and after theta burst stimulation (left), and time course of the amplitude (upper right) and slope (bottom right) of each EPSP [green: before, red: after theta burst stimulation]

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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.