AAI	animal-assisted intervention
ALFF	amplitude of low-frequency fluctuation
dlPFC	dorsolateral prefrontal cortex
DMN	default mode network
ECN	executive control network
EPP	existential phenomenological psychotherapy
FC	functional connectivity
fMRI	functional magnetic resonance imaging
ICA	independent component analysis
IMCP	individual meaning-centered psychotherapy
KYN	kynurenines
KYNA	kynurenic acid
LLD	late-life depression
MAOI	monoamine oxidase inhibitors
MCGP	meaning-centered group psychotherapy
MCP	meaning-centered psychotherapy
NMDA	N-methyl-D-aspartate
mPFC	medial prefrontal cortices
PCC	posterior cingulate cortex
PRI	pet-robot intervention
PTSD	posttraumatic stress disorder
ReHo	regional homogeneity
SNRI	selective norepinephrine reuptake inhibitor
SSRI	selective serotonin reuptake inhibitor
SN	salience network
TRD	treatment-resistant depression
TRP	tryptophan