New Tests of Viability Using Fluorescence or Ionic Activity

New Tests of Viability Using Fluorescence or Ionic Activity 

Studies of the laminar distribution of ionic activity made with multiple electrodes showed the largest changes in K o and Ca jo to occur near the cell bodies in the striatum pyramidale (Fig. 14) rather than regions containing dendrites and nerve terminal. Thus in these particular experiments the distribution of ionic changes may prove an unreliable index of 

Two related questions of high intrinsic interest are whether the dendrites and cell body of neurons differ in their membrane properties, and whether the formal neuronal model developed initially by Rail to describe the motoneuron (Jacks et aL, 1975 Redman, 1976 Rail, 1962, 

In a recent study, Turner and Schwartzkroin (1980) attempted to estimate the voltage and current transfer between the soma and dendrites of CAl pyramidal cells of the guinea pig hippocampus, by recording from the cells intracellularly and then injecting HRP to visualize the detailed anatomy of the dendritic tree. All of the cells were oriented within the transverse plane of the slice and almost completely contained within one 75-pm section cut parallel to the surface of the slice. Although a few processes were found in adjacent sections, the major part of the tree was extremely flat and only 25-50 pm thick. 

In this study, presumably of the larger CAI cells, the average membrane resistance of 12 pyramidal cells, which were subsequently found to be intensely stained, was 27.8 7.4 Mil (mean standard deviation), and the largest time constant averaged 10.9 3.2 msec. 

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