Hello tototo,
Hep C infects not only the liver. It infects many other things including your brain and nerves.
We commonly see cognitive impairment (aka brain fog), fatigue and untreatable depression in patients with Hep C.
These other impacts of Hep C are called the extrahepatic manifestations and here is a good article about them:
www.ncbi.nlm.nih.gov/pmc/articles/PMC4735500/
Specifically on the brain, there is something called "functional brain imaging" that shows how a person's brain is working. A Google Search for "functional brain imaging hepatitis c" will bring up articles like:
neuro.psychiatryonline.org/doi/pdf/10.11....neuropsych.17080163
www.ncbi.nlm.nih.gov/pmc/articles/PMC5272938/
www.ncbi.nlm.nih.gov/pubmed/29536563
The last one concludes:
CONCLUSIONS:
Patients with chronic hepatitis C exhibit cerebral metabolite alterations and structural or functional neuroimaging abnormalities, which sustain the hypothesis of hepatitis C virus involvement in brain disturbances.
In English, Hep C messes with patients brains, and not in a good way.