This atlas of the budgerigar (Melopsittacus undulatus) brain was prepared from 49 transverse sections 25 micrometers apart, ranging from 6.00 mm anterior to 6.00 mm posterior to the interaural line. In order to produce the plane of section used in this atlas, the head was placed in a Kopf stereotaxic atlas with the upper bill tip positioned 5 mm below the interaural line. The reader should note that an international group of scientists has proposed a revised nomenclature for the avian brain which is different from the traditional nomenclature (i.e. Karten and Hodos, 1967). This new nomenclature is used in this atlas of the budgerigar brain.
| Abbreviation | Name of Neural Structure |
| A | Arcopallium |
| AAC | Central nucleus of the anterior arcopallium |
| AACd | Dorsal subdivision of AAc |
| AACv | Ventral subdivision of AAc |
| AL | Ansa lenticularis |
| An | Nucleus angularis |
| AP | Area Pretectalis |
| Ap | Posterior arcopallium |
| APH | Area parahippocampalis |
| Bas | Nucleus basorostralis |
| BCD | Brachium conjunctivum decendens |
| CA | Commissura anterioris |
| Cb | Cerebellum |
| CbL | Nucleus cerebellaris lateralis |
| CbM | Nucleus cerebellaris medialis |
| CHCS | Tractus corticohabenularis et corticoseptalis |
| CIO | Capsula internus occipitalis |
| CP | Commissura posterior |
| CS | Nucleus centralis superior (Bechterew) |
| Ct | Commissura tectalis |
| CTz | Corpus trapezoidea |
| D | Nucleus of Darkschewitz |
| DIP | Nucleus dorsointermedius posterior thalami |
| DLAmc | Nucleus dorsolateralis anterior thalami pars magnocellularis |
| DLL | Nucleus dorsolateralis anterior thalami pars lateralis |
| DLP | Nucleus dorsolateralis posterior thalami |
| DMm | Magnicellular nucleus of the dorsomedial thalamus |
| DMP | Nucleus dorsomedialis posterior thalami |
| E | Entopallium |
| EM | Nucleus ectomammillaris |
| FLM | Fasciculus longitudinalis medialis |
| FPL | Fasciculus prosencephali lateralis |
| FPM | Fasciculus prosencephali medialis |
| FU | Fasciculus uncinatus |
| GCt | Substantia grisea centralis |
| GP | Globus pallidus |
| HA | Hyperpallium apicalis |
| Hb | Habenula nucleus |
| HD | Hyperpallium densocellulare |
| HI | Hyperpallium intercalatus |
| Hp | Hippocampus |
| ICc | Central nucleus of the inferior colliculus |
| ICo | Nucleus intercollicularis |
| INP | Nucleus intrapeduncularis |
| IO | Nucleus isthmo-opticus |
| IP | Nucleus interpeduncularis |
| Ipc | Nucleus isthmi pars parvocellularis |
| IS | Nucleus interstitialis |
| L1 | Lamina 1 of Field L |
| L2a | Lamina 2a of Field L |
| L2b | Lamina 2b of Field L |
| L3 | Lamina 3 of Field L |
| La | Nucleus laminaris |
| LL | Lateral lemniscus |
| LLd | Dorsal nucleus of the lateral lemniscus |
| LLI | Intermediate nucleus of the lateral lemniscus |
| LLv | Ventral nucleus of the lateral lemniscus |
| LMmc | Nucleus lentiformis mesencephali pars magnocellularis |
| LoC | Locus coeruleus |
| LSt | Lateral striatum |
| M | Mesopallium |
| MC | Nucleus magnocellularis |
| MLd | Nucleus mesencephalicus lateralis, pars dorsalis |
| MO | Oval nucleus of the mesopallium |
| MPv | Nucleus mesencephalicus profundus |
| MSt | Medial striatum |
| MStm | Magnocellular nucleus of the medial striatum |
| Mvm | Ventromedial mesopallium |
| N | Nidopallium |
| NAO | Oval nucleus of the anterior nidopallium |
| NAOm | Medial oval nucleus of the anterior nidopallium |
| NC | Nidopallium caudale |
| NFl | Frontal lateral nidopallium |
| NLC | Central nucleus of the lateral nidopallium |
| NLs | Supracentral nucleus of the lateral nidopallium |
| NI | nidopallium intermedium |
| NIDL | Nidopallium intermedium pars dorsolateralis |
| NIII | Nervus oculomotorius |
| nIII | Nucleus oculomotorius |
| NV | Nervus trigeminus |
| nV | Nucleus motorius nervi trigemini |
| nVd | Nucleus nervi trigemini descendens |
| nVI | Nucleus nervi abducentis |
| NVI | Nervus abducentis |
| NVII | Nervus facialis |
| nXIIts | Nucleus nervi hypoglossis pars tracheosyringealis |
| NIVL | Nidopallium intermedium pars ventrolateralis |
| Ov | Nucleus ovoidalis |
| OI | Nucleus olivaris inferioris |
| OM | Tractus occipitomesencephalicus |
| PaP | Nucleus papilloformis |
| PL | Nucleus pontis lateralis |
| PM | Nucleus pontis medialis |
| POA | Nucleus preopticus anterior |
| PrV | Nucleus sensorium principalis nervi trigemini |
| Pt | Nucleus pretectalis |
| PrV | Nucleus sensorius principalis nervi trigemini |
| R | Nucleus raphe |
| RPgc | Nucleus reticularis pontis caudalis pars gigantocellularis |
| RPO | Nucleus reticularis pontis oralis |
| Rt | Nucleus rotundus |
| Ru | Nucleus ruber |
| SAC | Stratum album centrale |
| SCd | Nucleus subcoeruleus dorsalis |
| SCv | Nucleus subcoeruleus ventralis |
| SGC | Stratum griseum centrale |
| SGF | griseum et fibrosum |
| SL | Nucleus septalis lateralis |
| SLu | Nucleus semilunaris |
| SM | Nucleus septalis medialis |
| SNc | Substantia nigra pars compacta |
| SOp | Stratum opticum |
| SPC | Nucleus superficialis parvocellularis |
| SpL | Nucleus spiriformis lateralis |
| SpM | Nucleus spiriformis medialis |
| SPO | Nucleus semilunaris parovoidalis |
| TN | Nucleus taeniae |
| TTd | Nucleus et tractus descendens nervi trigemini |
| VeD | Nucleus vestibularis dorsalis |
| VeM | Nucleus vestibularis medialis |
| VeS | Nucleus vestibularis superioris |
| VSt | Ventral striatum |