Neural Information Systems Theory: First-Order Thalamic Downsampling Instability and Second-Order Default Mode Network Integration Cascading Failure Hypothesis

Abstract— This paper introduces a novel neuroinformatics framework rooted in Status-Relational Entropy (SRE) dynamics to deconstruct the multi-tier gating mechanisms of the human brain from a cybernetics and digital signal processing (DSP) perspective. We model the brain as a distributed, multi-tier stepped dynamic defense system managing massive environmental data throughput. The primary gate relies on the Thalamic Reticular Nucleus (TRN), which functions as a hardware decimator and anti-aliasing low-pass filter to dissipate sensory white noise. The filtered parameters then cascade into the core physical topological axis of the Default Mode Network (DMN), specifically the posterior cingulate cortex and precuneus (PCC/PCu), acting as a higher-order software compressor and principal component extractor driven by memory-based causal templates. We hypothesize that the hidden structural vulnerability of Alzheimer’s Disease (AD) originates from early-stage dissolution of TRN inhibitory interneurons, causing leakage in primary downsampling. Consequently, high-dimensional signal aliasing overloads the cortex, forcing the DMN to increase its parameter rigidity for high-pressure integrative energy storage. By analyzing cleansed electrophysiological derivatives from the OpenNeuro dataset (ds004504) under 5Hz intermittent photic stimulation, our fine-grained time-slice analysis captured a non-linear, vertical upward mutation in instantaneous SRE spectral entropy precisely at the 4th second in the AD group. This timeline trajectory empirically validates the systemic cascading failure threshold triggered by clock skew and phase mismatch-induced destructive interference. Furthermore, multi-frequency matrix analysis reveals gender-specific non-linear phase transitions, including a variance explosion in elderly female AD subjects under 5Hz stimulation (\(\sigma^2 = 0.8687\)) and a rigid parameter lockup in elderly male AD subjects under 10Hz resonance (\(\sigma^2 = 0.3354\)). Finally, we propose non-invasive thalamic-targeted preventive interventions, emphasizing multimodal cross-frequency sensory pulse entrainment, autonomic vagal reverse drive, and input stream structural optimization via engineering dithering and acoustic harmonic recalibration to reset the system's dynamic capacitance. Audio S1. Audio Stimulus for Thalamic-DMN Gating Regulation. An 18-minute synthesized Baroque-style counterpoint acoustic stream at 44.1 kHz sampling rate, 16-bit PCM stereo. Low-frequency bands (20–90 Hz) are natively self-modulated with a 40 Hz sinusoidal envelope (15% modulation depth). The right channel incorporates a precise 9.0 ms interaural time delay for space-phase mismatch entrainment. A 10-second control reset (DMN meltdown window) is embedded every 5 minutes. Note: High-quality closed-back binaural headphones are strictly required for playback; otherwise, the gating regulation and entrainment effects will be rendered ineffective. Validation Note: The structural baseline of the proposed multi-tier gating channels has been rigorously verified via an independent macroscopic morphometric analysis utilizing the OpenBHB dataset containing 3,227 multi-site healthy brains across a full lifespan (6 to 88 years old). The empirical verification successfully identified the primary gate's hard formatting window sharply localized between 10.0 and 20.0 years old, and established a statistically significant (p = 4.157476e-02) variance contraction (std = 94.262609) within the DMN core among healthy female survivors over 65 years old. This structural stabilization baseline serves as a mandatory pre-pathological reference frame to support the proposed cascading failure hypothesis.