AD	Alzheimer’s disease
ADHD	Attention-deficit/hyperactivity disorder
ALS	Amyotrophic lateral sclerosis
APOE	Apolipoprotein E
ASD	Autism spectrum disorder
ASMs	Antiseizure medications
BBB	Blood–brain barrier
BDNF	Brain-derived neurotrophic factor
CJD	Creutzfeldt–Jakob disease
CNS	Central nervous system
C-sections	Caesarean section
ENS	Enteric nervous system
FMT	Faecal microbiota transplantation
FTLD	Fronto-temporal lobe Dementia
GABA	Gamma-aminobutyric acid
GF	Germ-free
GI	Gastrointestinal
HPA-axis	Hypothalamic-pituitary-adrenal axis
IL	Interleukin
MDD	Major depressive disorder
MGBA	Microbiota–gut–brain axis
MHC	Major histocompatibility complex
MS	Multiple sclerosis
MSA	Multisystem atrophy
NDDs	Neurodegenerative diseases
PD	Parkinson’s disease
PFC	Prefrontal cortex
SCFAs	Short-chain fatty acids
SCZ	Schizophrenia
SGA	Second-generation antipsychotics
TLE	Temporal lobe epilepsy
WD	Wilson–Konovalov disease