Fig. 2

Cortical neurofilament immunoreactivity (IR) and distribution across cortical brain regions. (a, c) Cortical p-NfM/H and (b, d) NfL immunoreactivity are shown for controls, PD and PDD/DLB groups. The first row (a, b) shows the overall neurofilament immunoreactivity across all cortical regions examined, with percentage differences compared to controls indicated at the top of the graph; every data point represents the averaged neurofilament immunoreactivity across all cortical regions of a donor , and the clinical groups are indicated by shapes, showing that PDD and DLB donors behaved similarly. Moreover, images of p-NfM/H (a) and NfL stainings (b) show that p-NfM/H targets the axons, while NfL targets both the neuronal soma and its processes. The second row (c and d) shows the regional neurofilament immunoreactivity in the 7 cortical regions analysed. Percentage differences (c) between p-NfM/H immunoreactivity in PD vs controls and (d) between NfL immunoreactivity in PDD/DLB vs controls are shown for brain areas hosting a significant difference. From these data, we can infer that p-NfM/H was uniformly increased across the cortical areas analysed in both PD and PDD/DLB, while NfL was increased specifically in the entorhinal and parahippocampal cortex in PDD/DLB. *P < 0.05, **P < 0.01, ***P < 0.001 when compared to controls. ACC: anterior cingulate cortex; AI: anterior insula; DLB: Dementia with Lewy Bodies; ENTC: entorhinal cortex; FUSG: fusiform gyrus; IR: immunoreactivity; MTG: middle temporal gyrus; NfL: neurofilament light chain; PHG: parahippocampal gyrus; PD: Parkinson’s disease; PDD: Parkinson’s disease dementia; p-NfM/H: phosphorylated neurofilament medium and heavy chain; SFG: superior frontal gyrus