Initially patch pipettes were designed to record elementary events from muscle and neurons. A recording configuration that proved to be convenient to study signaling in nerve cells embedded in their (almost) natural environment was designated as whole-cell-recording. In this Lecture I will summarize work designated to throw light on electrical signaling within a neuron, between dendrite branches, soma and nerve terminal. Possible function of this intra-neuronal electrical signaling are coincidence detection of spatially separated synaptic inputs and, on a longer time scale, the induction of mechanisms that underlie synaptic plasticity. They depend on the newly discovered active electrical properties of dendrites (backward propagating and forward propagating action potentials). What are possible functions of dendritic active voltage dependent excitability with respect to network dynamics? One obvious function is the interaction of an actively propagating dendritic electrical signal with locally restricted synaptic signals. On a shorter time scale it mediates coincidence detection of several synaptic inputs by a pyramidal neuron and, on a longer time scale, it induces changes in synaptic strength referred to as spike timing dependent plasticity. These discoveries provide some of experimental advances in the field of neuroscience that can claim to provide a cellular basis for understanding a brain function as a whole. In vivo recordings from the cortex major output neurons in the intact brain, pyramidal cells have indicated that coincidence detection and spike time dependent changes in connectivity are indeed implemented in pyramids of the intact brain. They critically determine the output pattern of action potentials, that is differentially read by their target cells in cortex and subcortical nuclei, e.g. in cortical and thalamic target cells of layer5 thick tufted pyramids.