Diff pathways in the ns correspond to a different behavioral functions: cell recordings a)single cell recordings, precision. Which cells do what: e. g. , mapping out visual cortex. a)mass activity of neurons, gross behaviour, e. g. , stages of sleep, learning, remembering. Know what their doing? a)we can excise a neuron, look at in a pitri dish. Now can look at neuron inside an alive animal and see how it fxns. Clamps into animals head to keep in place. Excise a piece of the skull and insert an electrode and monitor the neuron in question. Hugal and weasel won a nobel prize for mapping out the visual cortex,our understanding of visuals and ability to recognize images is due to single cell rec. Nuerons respond to lines moving in a direction= visual: people have a sensory relation to seizures ie- burnt food can tigger sezuire. Only treatment was to cut out part of brain causing the seizures. Maped out 2 parts of the brain "homunculi".