Membrane time constant as a tool to assess cell degeneration.

Changes in neuronal surface area may be monitored by measuring the plasma membrane capacitance [8]. Membrane time constant (tao m) is given by the product of the membrane resistance (rm) and membrane capacitance (Cm), tao m = rm Cm. Thus, when membrane resistance is kept constant at a steady state (resting), membrane time constant can reflect the size of neuronal surface area.

Commissural responses of rat retrohippocampal neurons.

Synaptic responses of commissurally activated rat subicular and entorhinal neurons were studied intracellularly in vivo by stimulating the contralateral dentate gyrus. The most prominent synaptic responses in both subicular and entorhinal neurons were inhibitory postsynaptic potentials (IPSPs). IPSPs were generated in combination with antidromic spikes and/or excitatory postsynaptic potentials (EPSPs) and orthodromic spikes.

Multimodality imaging of brain structures for stereotactic surgery.

An image analysis system was developed for stereotactic neurosurgery that allows the simultaneous display of brain images from different imaging devices obtained in different orientations. The system is based on a stereotactic frame and a microcomputer and features an easy user interface together with point registration and region of interest analysis in three-dimensional space. A dynamic multi-image environment allows for simultaneous display of magnetic resonance, computed tomography, digital subtraction angiography, and positron emission tomography images in multiple windows, adjusted for common coordinates with reference to stereotactic frame fiducial markers.