Lesion
Because neurons are the only cells that can conduct electric current, answer to your question would be neurons.
The information each neuron processes determines how strong the action potential (electrical current) is within each neuron. An example of studying the electrical activity is by using temperature. The neurons which detect the temperature change are called sensory neurons. If you stimulate the neurons by leaving your fingertip in cold water for an adequate amount of time the electrical current within each neuron is increased as the temperature of your fingertip drops. The neurons within the fingertip sense the temperature drop and emit the electrical current, then the next neuron senses the temperature drop as the fingertip is held in the cold water and emits a stronger electrical current, the colder temperature in the next neuron as your finger is held in the water emits an even higher frequency and so on until the message arrives at the spinal cord and is then sent to the brain through the now very strong electrical current within the neurons informing it of the temperature decrease and then resulting in action outcome.
electrical and chemical impulses.
neurons
Neurons are the conducting cells of nerve tissue. The neurons transmit the electrical charges and chemical signals via the synapses.
electrical impulses
yes
Dendrites
Nervous tissue is composed of neurons that use electrical signals to transfer impulses throughout the body.
Neurons are in your brain, and are organic. While electrical cords are synthetic and supply electronics and many appliances or home decorating (such as lamps) with power.
yes they do
Contact between neurons, as you put it, is achieved through electrical impulses towards and from your brain.