Hcrt

Spatial tier: RESTRICTED · Class: OTHER · Top region: LHA (Lateral hypothalamic area) · Positive regions: 17/554

43.8Discovery Score
35.4Targetability Score
CEvidence grade C
What this means: Hcrt: fine CCF profile is restricted toward LHA (top regions: LHA, PeF, DMH, PSTN, TU; 17 positive regions); direct spatial validation is still required.

Function in LHA: evidence, prediction, innovation

Gene function
HCRT encodes prepro-orexin, cleaved into the neuropeptides orexin-A (hypocretin-1) and orexin-B (hypocretin-2). These peptides act on two Gq-coupled receptors, OX1R and OX2R, to depolarise target neurons throughout the arousal system. Orexin neurons are found only in the lateral hypothalamus and adjacent perifornical area but project brain-wide; loss of these neurons causes narcolepsy with cataplexy in humans and dogs.
Region function
The lateral hypothalamic area is a heterogeneous hub of orexin, MCH, GABAergic and glutamatergic neurons that integrates arousal with feeding, reward seeking and autonomic output, projecting widely from cortex to spinal cord.
Published in this region
direct Direct and foundational. Chemelli et al. 1999 showed that orexin knockout mice have a narcolepsy phenotype with behavioural arrests and fragmented sleep, establishing the gene-region-behaviour link. Subsequent work has mapped the lateral hypothalamic orexin population in detail: Tyree et al. 2018 review its role as a hub for arousal and motivation, and Li et al. 2022 showed that hyperexcitable lateral hypothalamic arousal circuits drive sleep instability in ageing mice.
Predicted function
Prediction: the open question is not whether orexin promotes arousal but how graded peptide release encodes motivational state. Fine-grained manipulation - partial, adult-onset Hcrt knockdown or graded chemogenetic tuning of orexin neurons - is predicted to reveal a dose-dependent separation in which modest reduction selectively impairs effortful, high-cost reward seeking and arousal during anticipation, while only substantial loss fragments sleep-wake architecture; dual orexin receptor antagonists such as suvorexant should reproduce the sleep phenotype without the motivational one at low doses.
Innovation
★☆☆☆☆ 1/5 Orexin in the lateral hypothalamus is one of the most intensively studied peptide-region systems in all of neuroscience, with an approved drug class built on it.
Tools
Hcrt knockout, orexin-ataxin-3 ablation and orexin-Cre mice; Hcrt-IRES-Cre and orexin-eGFP reporters; orexin-A and orexin-B peptides; dual orexin receptor antagonists suvorexant, lemborexant and almorexant; selective antagonists SB-334867 (OX1R) and TCS-OX2-29 (OX2R); orexin sensors for in vivo release imaging.
References

Direct evidence located at the region

Hcrt Allen ISH at the CCF centroid of LHA

Allen ISH experiment 79913316, section image 79798209 (section 148): the section that contains the CCF centroid of Lateral hypothalamic area according to the Allen image-to-atlas alignment (reference_to_image), with a 2 mm window around that point. Left: whole section, red box = window. Middle: ISH signal. Right: Allen's expression-mask view of the same window. open this image in the Allen viewer

Look it up yourself: Allen Mouse Brain ISH for HcrtAllen reference atlas: LHA (structure 194)ABC Atlas MERFISH viewer(in the ABC Atlas choose dataset MERFISH-C57BL6J-638850-CCF, colour cells by gene "Hcrt" or by parcellation_substructure "LHA")All genes confined to LHA + 3-D brain

Direct spatial evidence

MERFISH REGION LOCATOR
LHA MERFISH region locator
Real single-cell MERFISH coordinates for the LHA (Lateral hypothalamic area) section -- our own ground-truth data, showing exactly where this region sits, independent of whether the Allen ISH section below is easy to read.

Regional expression figure

Hcrt regional expression profile

Predicted WMB × fine-CCF profile; not direct full-transcriptome spatial measurement.

Spatial profile

LHA
0.295
PeF
0.286
DMH
0.221
PSTN
0.179
TU
0.172
B
0.162
TMv
0.158
PMv
0.15
VMH
0.144
PVHd
0.142
PH
0.137
SO
0.136
OV
0.135
STN
0.131
ENTm5
0.13
DR
0.122
SPFm
0.119
ENTm3
0.116
ARH
0.115
AHN
0.115

Evidence and specificity

Evidence status
PREDICTED_FINE
Direct sources
None; predicted localization only
Exclusive threshold
12 positive regions out of 554
Spatial specificity
0.321
Top-region fraction
0.069
Filter status
PASS

Interpretation limits