Tac1

Spatial tier: STRICT_EXCLUSIVE · Class: OTHER · Top region: OT (Olfactory tubercle) · Positive regions: 8/554

45.1Discovery Score
43.7Targetability Score
CEvidence grade C
What this means: Tac1: predicted fine-region profile is strict-exclusive, with 8 positive regions out of 554 (limit 12); direct spatial validation is required.

Function in OT: evidence, prediction, innovation

Gene function
Tac1 encodes preprotachykinin A, processed into substance P and neurokinin A. Substance P acts at the Gq-coupled NK1 receptor (Tacr1), raising calcium and exciting targets; it co-transmits in striatal direct-pathway neurons and nociceptive afferents.
Region function
The olfactory tubercle, the olfactory ventral striatum, combines olfactory bulb input with VTA dopamine to encode odour valence, reward and approach via D1/D2 spiny neurons and islands of Calleja.
Published in this region
expression only Furuta et al. 2002 found PPTA-immunoreactive neurons concentrated in the OT dense cell layer, largely co-expressed with preprodynorphin, while PPTB (Tac2) cells are nearly absent; Zhou et al. 2003 reported ~70% of OT neurons projecting to ventral pallidum are PPTA-positive; Ubeda-Banon et al. 2010 found substance P cells in human OT in Parkinson's disease.
Predicted function
Prediction: substance P is the direct-pathway co-transmitter of OT D1 neurons, released onto ventral pallidum and VTA during high-value odour cues to amplify approach. Chemogenetic activation of OT Tac1 neurons should drive odour and place preference; OT-restricted Tac1 deletion or intra-pallidal NK1R antagonism (L-733,060, aprepitant) should weaken reward-cue invigoration.
Innovation
★★★☆☆ 3/5 Tac1 in the tubercle has been known for decades, but nobody has used Tac1-Cre to dissect this ventral-striatal population.
Tools
Tac1-Cre / Tac1-IRES2-Cre knock-in drivers, Tac1 knockout mice, NK1R antagonists L-733,060 and aprepitant, substance P and NK1R antibodies; OT is reached stereotaxically, intersected with Drd1-Cre or Drd3-Cre.
References

Direct evidence located at the region

Tac1 Allen ISH at the CCF centroid of OT

Allen ISH experiment 1038, section image 101322922 (section 299): the section that contains the CCF centroid of Olfactory tubercle 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 Tac1Allen reference atlas: OT (structure 754)ABC Atlas MERFISH viewer(in the ABC Atlas choose dataset MERFISH-C57BL6J-638850-CCF, colour cells by gene "Tac1" or by parcellation_substructure "OT")All genes confined to OT + 3-D brain

Direct spatial evidence

MERFISH REGION LOCATOR
OT MERFISH region locator
Real single-cell MERFISH coordinates for the OT (Olfactory tubercle) 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

Tac1 regional expression profile

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

Spatial profile

OT
6
ACB
4.66
CP
3.79
PMv
3.58
PSTN
2.79
MH
2.05
FS
1.89
RO
1.62
SI
1.56
AON
1.56
MEA
1.47
Su3
1.42
VMH
1.35
FC
1.34
BST
1.33
DMH
1.31
SCsg
1.3
ICd
1.3
SO
1.28
SUM
1.27

Evidence and specificity

Evidence status
PREDICTED_FINE
Direct sources
None; predicted localization only
Exclusive threshold
12 positive regions out of 554
Spatial specificity
0.342
Top-region fraction
0.091
Filter status
PASS

Interpretation limits