<p>When examining ISH heatmaps of gene expression in the brain, I'm typically looking for above-average expression in the form of high z-scores but have also encountered imaging with negative z-scores. Interpreting positive scores as indicative that a region uses more of the protein that gene encodes makes sense to me, but what does it mean for a region to express that gene below average...is it actively avoiding that gene more so than other regions, and what are some biological reasons it might do that?</p>

CC BY-SA 4.0
2023-06-26T18:27:23.277Z
I think you just need to think about what a z-score is, and what z-score = 0 represents. Z-scores are not correlations.
Bryan Krause
CC BY-SA 4.0
2023-06-26T22:47:40.193Z
You're right, I was thinking about "correlation" in a non-statistical sense, and looking back it doesn't make much sense. I've edited the question to avoid using correlation interchangeably with deviation from the average.
Lambda
CC BY-SA 4.0
2023-06-26T22:56:57.313Z
Great, that helps a lot. But... the question now doesn't seem to make much sense. I mean, aside from Lake Wobegon, it's not really possible for everything to be *above* average in any group, is there? So, there really isn't an *explanation* needed, besides "You z-scored the data." Like my original comment started: think about what a z-score is, and what z-score = 0 represents.
Bryan Krause
CC BY-SA 4.0
2023-06-29T23:56:04.253Z
Sorry for not getting back sooner: you're completely right, after looking at an example paper that applied the data I realized that my question is kind of self-explanatory. Thanks for clearing it up!
Lambda
<measurement><neuroimaging><genetics>
Interpreting Negative Z-Scores Gene Expression
Lambda
# Interpreting Negative Z-Scores Gene Expression

(Asked by: username_0 on 2023-06-26)

When examining ISH heatmaps of gene expression in the brain, I'm typically looking for above-average expression in the form of high z-scores but have also encountered imaging with negative z-scores. Interpreting positive scores as indicative that a region uses more of the protein that gene encodes makes sense to me, but what does it mean for a region to express that gene below average...is it actively avoiding that gene more so than other regions, and what are some biological reasons it might do that?

**Tags:** measurement, neuroimaging, genetics

> **Comments:**
> **username_1**: I think you just need to think about what a z-score is, and what z-score = 0 represents. Z-scores are not correlations.  
> **username_0**: You're right, I was thinking about "correlation" in a non-statistical sense, and looking back it doesn't make much sense. I've edited the question to avoid using correlation interchangeably with deviation from the average.  
> **username_1**: Great, that helps a lot. But... the question now doesn't seem to make much sense. I mean, aside from Lake Wobegon, it's not really possible for everything to be *above* average in any group, is there? So, there really isn't an *explanation* needed, besides "You z-scored the data." Like my original comment started: think about what a z-score is, and what z-score = 0 represents.  
> **username_0**: Sorry for not getting back sooner: you're completely right, after looking at an example paper that applied the data I realized that my question is kind of self-explanatory. Thanks for clearing it up!  

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## 0 answers

