retinal achromatopsia, 162
retinal-hypothalamic pathway, 234
retrieval, memory, 222-23
retrograde amnesia, 223
retrograde neurotransmission, 115
reuptake inactivation, 64
reward pathways, 247-48
rhodopsin, 159, 160-62, 164f, 164-68, 165f, 272
rhythm
biological clock, 232-35
circadian, 232
cycle of sleep and wakefulness, 231, 233
ribose, 35
ribosomes, 33, 46
RNA polymerase, 117f
RNA (ribonucleic acid), 35-36, 46-47
R6éntgen, Wilhelm, 198
Rosa, 141
Ruffini, Angelo, 187
Ruffini endings, 187f
Sabina, Maria, 111
sabinene, 140
saccharin, 150-51
Sacks, Oliver, 195, 269
salicylic acid, 105
Salmonella, 125
saltatory conduction, 59
salt taste, 148
Salvia divinorum, 112
salvinorin, 112
saturated lipid, 30
saxitoxin (STX), 89-90