Feeling and Self-Referencing – Fundamental Differences between Parkinson’s and Alzheimer’s - Decolonial Neuroscience SfN 2025 Brain Bee Ideas
Feeling and Self-Referencing – Fundamental Differences between Parkinson’s and Alzheimer’s - Decolonial Neuroscience SfN 2025 Brain Bee Ideas
“Today we’ll talk about something deep: what happens when the body stops telling us we’re alive? And when the mind stops telling us who we are? Feeling and self-referencing is the foundation of consciousness. And in Parkinson’s and Alzheimer’s, this foundation is under attack.”
On Brain Damage and Interoceptive / Proprioceptive Capacities
Feature | Alzheimer’s | |
Type of disease | Neurodegenerative motor disorder (with cognitive effects) | Neurodegenerative cognitive disorder (with secondary motor effects) |
Most affected brain area | Substantia nigra (pars compacta) → reduced dopamine in the striatum (caudate nucleus and putamen) | Hippocampus, entorhinal cortex, progressing to parietal and frontal cortices |
Main neurotransmitter affected | Dopamine | Acetylcholine |
Type of degeneration | Death of dopaminergic neurons + Lewy body accumulation | Accumulation of beta-amyloid plaques and tau tangles |
Motor deficits | Highly pronounced: rigidity, bradykinesia, tremor, hypomimia, posture abnormalities | Mild in early stages; unstable gait in later stages |
Cognitive deficits | Appear later (Parkinson’s dementia in some cases) | Appear early (episodic memory, orientation, language) |
Interoception / Proprioception | Directly impaired — low bodily awareness, reduced facial expression, impaired movement perception | Indirectly impaired — due to loss of orientation in time and space, and degradation of subjective identity |
Example of interoceptive loss | The patient doesn’t notice how little their face or body is expressing → doesn’t feel they are "being" | The patient doesn’t remember being → loses the subjective context of their body in time and relationships |
In Neuroanatomical Terms
Parkinson’s:
Damage in the nigrostriatal pathway (substantia nigra → striatum):
⟶ Impairs voluntary and expressive motor planning and execution.Degeneration in brainstem nuclei (including locus coeruleus, nucleus basalis, ventral tegmental area).
Eventually affects the dorsolateral prefrontal cortex, impairing executive function and interoceptive attention.
Alzheimer’s:
Begins in the hippocampus (episodic and spatial memory) and entorhinal cortex (gateway between hippocampus and neocortex).
Progresses to the posterior parietal cortex (body schema, visuospatial orientation).
Evolves into frontal areas and anterior cingulate cortex, disrupting metacognition, emotional regulation, and self-image.
How Does This Relate to “Feeling and Self-Referencing”?
Parkinson’s:
Facial and body movement lose amplitude, causing the patient to lose the signals that help them feel present.
Proprioception is silenced: they don’t perceive they’re slouched, that their face is “off,” or that the body isn’t responding.
Motor interoception (feeling tension, movement, fine adjustments) is reduced, affecting the awareness of the “Tensional Self” (in your framework).
This is the collapse of “I am what I move.”
Alzheimer’s:
Awareness of time and place deteriorates first.
The patient still feels the body, but doesn’t know where or who they are — internal reference is lost in narrative time.
Emotional interoception (emotions linked to memories) also disconnects: the body feels, but doesn’t recognize why.
This is the collapse of “I am what I remember.”
Key Highlights
Parkinson’s is the death of movement as a reference for the SELF.
⟶ Interoception loses its constant source of update: the body goes silent, the face freezes, the SELF becomes dereferenced.Alzheimer’s is the death of narrative as a reference for the SELF.
⟶ The body still feels and moves, but no longer knows who feels or why. It’s the SELF without a story.In both, the foundation of “feeling oneself being” is compromised.
But in opposite directions:Parkinson’s = body present without a referenced SELF
Alzheimer’s = body without time or narrative to reference the SELF
Connecting to Our Concepts
Concept | Alzheimer’s | |
Zone 2 | Collapses due to lack of micro-adjustments and motor feedback | Collapses due to fragmented metacognition and narrative |
REM Tonic | Fails to reintegrate expressive patterns | Fails to consolidate episodic memory with embodied presence |
Apus (expanded proprioception) | Interrupted in facial expression and posture | Still present, but unanchored from narrative |
Fruição (Enjoyment/Flow) | Reduced due to constant basal tension and muscular rigidity | Reduced due to temporal disconnection and emotional dissonance |
Tensional Selves | Frozen in the body | Dissolved in memory |
