Human fear conditioning is related to dopaminergic and serotonergic biological markers.
Biological markers for acquisition and extinction of fear conditioning were studied in 40 individuals selected for displaying either good or poor acquisition of fear conditioning. as estimated by the skin conductance response. Participants with a short serotonin transporter (5-HTT) promoter allele or low monoamine oxidase activity in platelets (trbc-MAO) displayed better acquisition than those with only long alleles or high trbc-MAO, whereas participants with a long dopamine D4 receptor (D4DR) exon III allele showed delayed extinction compared with those with only short alleles. The findings, that D4DR exon III and 5-HTT promoter genotypes and trbc-MAO activity are related to human fear conditioning, a basic form of associative learning, are consistent with animal studies suggesting a genetic contribution to fear conditioning. The authors suggest that in humans these genetic mechanisms are partly dopaminergic and serotonergic in origin.
Garpenstrand
H
H
Department of Neuroscience, Uppsala University, Sweden.
Annas
P
P
Ekblom
J
J
Oreland
L
L
Fredrikson
M
M
D000483:Alleles; D001143:Arousal / Q000502:physiology*; D001245:Association Learning / Q000502:physiology; D015415:Biomarkers / Q000097:blood; D001792:Blood Platelets / Q000201:enzymology; D002352:Carrier Proteins / Q000235:genetics; D003214:Conditioning, Classical / Q000502:physiology*; D004298:Dopamine / Q000502:physiology*; D005239:Fear / Q000502:physiology*; D005712:Galvanic Skin Response / Q000502:physiology; D005838:Genotype; D006801:Humans; D008562:Membrane Glycoproteins / Q000235:genetics; D026901:Membrane Transport Proteins; D011939:Mental Recall / Q000502:physiology; D008995:Monoamine Oxidase / Q000097:blood; D009419:Nerve Tissue Proteins; D011401:Promoter Regions, Genetic / Q000235:genetics; D017448:Receptors, Dopamine D2 / Q000235:genetics; D050638:Receptors, Dopamine D4; D012701:Serotonin / Q000502:physiology*; D050486:Serotonin Plasma Membrane Transport Proteins
D015415:Biomarkers; D002352:Carrier Proteins; C493599:DRD4 protein, human; D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins; D009419:Nerve Tissue Proteins; D017448:Receptors, Dopamine D2; C493230:SLC6A4 protein, human; D050486:Serotonin Plasma Membrane Transport Proteins; D050638:Receptors, Dopamine D4; D012701:Serotonin; D008995:Monoamine Oxidase; D004298:Dopamine