a cell. the pipette is filled with ionic solution, and a silver wire is placed in the solution to conduct and amplify electrical signals. the ion solution can be varied and drugs can be delivered through the micropipette to study the effects of current under various conditions. receptor and voltage-gated channel antagonists are often applied (i.e. nickel used to block nmda receptors) in order to study the effects of ion channels on dendritic spike initiation. current injection is often paired with patch clamp recordings in order to observe current modulation due to various experimental factors. extracellular electrophysiology tetrode recording methods have also been shown to occasionally allow for observation of dendritic membrane potentials and dendritic action potentials. interestingly, the chronic recording paradigm that demonstrated this also showed that dendritic voltage properties exhibited egocentric spatial maps comparable to pyramidal neurons. this rare phenomenon may be due to a glial sheath forming around the tetrode tips, creating a high impedance sea, similar to a gigaohm seal in patch recordings, that allows for such small and localized voltage measurement to be made. staining and labeling staining and labeling techniques are often used in microscopy to help identify specific structures in a cell. staining usually involves the use of dyes that are absorbed by various cell structures at different rates. labeling involves the use of fluorescence to identify specific molecules. fluorophores, fluorescent molecules, may be directly attached or attached to an antibody in order to detect a specific target. in the case of dendritic spikes, staining and labeling are used to identify and quantify the presence of certain voltage-gated channels. for example, rabbit polyclonal antibodies raised against synthetic peptide sequences have been used to identify the presence of nav1.2, nav1.3, and nav1.6 sodium channels in dendrites of the globus pallidus neuron. computational modeling computational modeling of neurons, artificial neural networking, has become a very popular tool in investigating the properties of neuronal signaling. these models are based on biological neural networks. computational modeling can be used to study single neurons, groups of neurons, or even networks of neurons. this field has generated much interest and serves as a tool for all branches of neuroscience research including dendritic spike initiation.