opium and opioids, 104-6
psychedelics, 109-13
sedative-hypnotics, 101-4
psychopharmacology, 93, 98
psychosis, 108
Psychotria viridis, 112
pungency, 153,156
Purkinje cell, 194
Purkyng, Jan, 194
quantum mechanics, 38-39, 256
quaternary amine, 31
quaternary structure, protein, 35
2-quinolinemethanethiol, 142, 143radial muscles, iris, 76, 76f
radiation, 158
Ramachandran, V. S., 192
Ramon y Cajal, Santiago, 17, 18f, 118, 119f, 120, 167f, 194f, 210f
random walk, 125-26
Ranvier, Louis—Antoine, 58
raphe nuclei, 79f, 209
rapid eye movement (REM), sleep, 235-36, 238, 240
receptive field, 168, 170, 188, 190
reductionism, 255
refractory period, 57
reproductive cycles, 232-33
retina, 159, 159f, 234
cone and rod distribution, 162f
cone and rod photoreceptor cells, 160f
drawing by Ramon y Cajal, 167f
layers of cells in, 167-68
retinal, 165-66