scaler electric potential

vector magnetic potentials

retarded potentials

graded (local) potentials

Postsynaptic potentials are changes in the membrane potential of the postsynaptic terminal of a chemical synapse. Graded potentials are changes in membrane potential that vary in size, as opposed to being all-or-none, and are not postsynaptic potentials.

As in mentally retarded, yes, only something with a brain can be mentally retarded. The GROWTH of plants can be retarded, which means they are not growing as fast as they should.

About 10% of the mentally retarded population is considered moderately retarded.