This lecture series covers the biophysics of neurons and synapses, including membrane potential, action potentials, synaptic transmission, glutamatergic excitation, GABAergic inhibition, in vivo techniques, brain function, behavior, voltage-gated channels, action potential propagation, whole-cell recordings, neurotransmitter release, synaptic plasticity, dendritic spines, inhibitory synaptic conductances, benzodiazepines, neocortical inhibition, brain imaging, in vivo electrophysiology, sensorimotor interactions, sensory perception, learning, brain dysfunction, and concluding remarks.