diff --git a/content/dis_pd.html b/content/dis_pd.html
index 4bc7c3615a8c8dc23f1bdf79798fa4107d3e1b3c..d4a59ae9cb3eff978cf8aa0b0605efe4a36bf38f 100644
--- a/content/dis_pd.html
+++ b/content/dis_pd.html
@@ -1,7 +1,7 @@
 ---
 title: Parkinson's disease
 author: Vesa Oikonen
-updated_at: 2023-02-02
+updated_at: 2023-11-17
 created_at: 2017-11-16
 tags:
   - Alpha-synuclein
@@ -21,7 +21,10 @@ fatigue. The pathological process in PD starts long before the clinical diagnosi
 
 <p><a href="./target_dopamine.html">Dopaminergic</a> degeneration is an age-related
 process, but in PD the loss of dopaminergic neurons in the substantia nigra is much faster than 
-in normal ageing. Parkinsonism is usually caused by idiopathic PD, but can be seen in patients
+in normal ageing. The volumes of caudate, putaminal, and thalamic nuclei are negatively correlated 
+with age in healthy subjects, and significantly smaller in PD 
+(<a href="https://pubmed.ncbi.nlm.nih.gov/8294897/">Lisanby et al., 1993</a>).
+Parkinsonism is usually caused by idiopathic PD, but can be seen in patients
 without dopaminergic deficit, and is prevalent in disorders such as progressive supranuclear palsy,
 multiple system atrophy, and microvascular disease. Lesion network mapping suggests that claustrum
 has a central role in parkinsonism