Stage-Progressive Subcortical BOLD Signal Dynamics in Alzheimer's Disease

This deposit contains the analysis code and derived results supporting the paper: "Stage-Progressive Subcortical BOLD Signal Dynamics in Alzheimer's Disease: Hippocampal Hyperactivation, Thalamic Rigidification, and Pallidal Gate Dysregulation" Ryan W. Malone, Independent Researcher, April 2026. Resting-state fMRI was analysed in 88 ADNI participants (CN=59, MCI=7, AD=22)to characterise BOLD signal variance, AR1, and instability in thalamus,hippocampus, and pallidum across diagnostic stages. Key findings: - Hippocampal BOLD variance significantly elevated in AD vs CN (d=-0.658, p=.010) - Thalamus-to-hippocampus variance ratio declines CN->MCI->AD (p=.032) - Pallidal dynamics peak at MCI stage (d=0.777 CN vs MCI) before collapsing in AD - Pattern consistent with compensatory hyperactivation followed by gate rigidification - Time-shift randomization confirms thalamic instability at MCI as genuine signal (p_perm=.000): thalamic instability and thal/hippo instability ratio both survive 500-permutation time-shift validation in the CN vs MCI contrast