Kahlus Root Technical Spec

Scope

Kahlus is a staged research program for noninvasive brain/body state measurement. The root model should stay concrete:

sensor/task history
  -> modality tokenizers
  -> temporal latent-state model
  -> perturbation-response operator
  -> future response profile + uncertainty

This is a research scaffold, not a clinical decision system.

Versions

Kahlus v1

Purpose: EEG forecasting and representation baseline.

EEG patch tokenizer
+ SSM/Transformer encoder
+ latent z_t
+ future EEG decoder

Loss:

L_v1 = lambda_1 MSE(Y_hat, Y) + lambda_2 MAE(Y_hat, Y) + lambda_3 L_smooth
L_smooth = sum_t ||Y_hat_{t+1} - 2Y_hat_t + Y_hat_{t-1}||_2^2

Role: strict baseline/evidence lane. Ridge and persistence baselines are results, not scaffolding.

Kahlus v2

Purpose: multimodal observation-operator model.

z_{t+1} = f_theta(z_t, u_t, s)
y_hat_t^(m) = O_m(z_t)

Initial operators:

O_EEG = temporal decoder
O_pupil = MLP/readout
O_HRV = MLP/readout
O_behavior = MLP/readout

Kahlus v3

Purpose: perturbation-response modeling.

C_K(h_t) = [P(tau | h_t, a_1), ..., P(tau | h_t, a_K)]

Public datasets only partially support this. Full v3 needs structured history, task/perturbation, and future multimodal response data.

Inputs And Outputs

Inputs may include EEG, webcam pupil/gaze, PPG/HRV, reaction time, task events, self-report sliders, context logs, and optional fNIRS later.

Outputs include future signal prediction, reward/stress response profile, uncertainty, and feature/quality reports.

Baselines

Minimum baselines:

• persistence

• train mean

• linear ridge

• autoregressive ridge

• MLP

• TCN

• Transformer

• SSM fallback

• direct translation baseline for cross-modal tasks

Baselines come before Kahlus model claims.

Evaluation Criteria

• subject-held-out split audit

• site/dataset-held-out audit when datasets support it

• no overlapping windows across splits

• finite metrics

• baseline table present

• quality flags reported

• evidence gate blocks broad and clinical claims

Claim Boundaries

Allowed: response-profile measurement, reward/stress task prototype, biomedical research scaffold, non-diagnostic biomarker exploration, synthetic and prototype-stage evidence.

Blocked: diagnosis, treatment, depression/PTSD/anhedonia detection, epilepsy diagnosis, clinical decision system, proven brain foundation model, consciousness device, God Helmet, neurostimulation therapy.

Citations To Verify

Reference	Why It Matters	citation_status
LFADS	neural population dynamics baseline	needs_verification
NDT	neural data Transformer baseline	needs_verification
BIOT	biosignal representation baseline	needs_verification
LaBraM	EEG representation baseline	needs_verification
NeuralBench	benchmark context	needs_verification
EEG Foundation Challenge	EEG benchmark context	needs_verification
WESAD	stress/physiology dataset candidate	needs_verification
DEAP	affect/physiology dataset candidate	needs_verification
SEED	affect EEG dataset candidate	needs_verification
CHB-MIT	seizure EEG dataset candidate	needs_verification
TUH/TUSZ	clinical EEG dataset candidate	needs_verification