Ariel Feldman
Advised by Dr. Caleb Kemere
A Machine Learning Approach to Predicting Occurrence of Sharp-Wave Ripple Complexes
Figure credit: Etienne Ackermann
What Are Sharp-Wave Ripples?
Colgin et al. Nature Reviews, 2016
Why Do We Need Prediction?
-
Missing approx. 40 - 60% of the SWR
- Never interrogated ripple generation
- Validation of in vivo interaction
-
Research context
- Interact with memory recall & consolidation
- Analyze impact on decision-making
Objective
Design Challenges
Goal: Apply machine learning techniques towards building a realtime closed loop SWR disruption system.
-
Anomalous event
- Ripples happen rarely
- Complex classification problem
-
Loss value
- Weighting loss misclassifications
- Custom function
- Must be realtime applicable
Spectral Domain
Sensitivity
Convolutional vs. Recurrent
Convolutional Architecture
Multi-Layer Perceptron
CA1
CA2
CA3
Weighting Misclassification
def sensitivity(y_true, y_pred):
true_positives = K.sum(K.round(K.clip(y_true * y_pred, 0, 1)))
possible_positives = K.sum(K.round(K.clip(y_true, 0, 1)))
return true_positives / (possible_positives + K.epsilon())
def specificity(y_true, y_pred):
true_negatives = K.sum(K.round(K.clip((1-y_true) * (1-y_pred), 0, 1)))
possible_negatives = K.sum(K.round(K.clip(1-y_true, 0, 1)))
return true_negatives / (possible_negatives + K.epsilon())
t = 1
class_weight={
0: 1,
1: len(np.where(dfy_train == 0)[0])/ len(np.where(dfy_train == 1)[0]) * t
}
How Will We Approach This?
-
Ensemble/Cascade Learning
- Multiple mediocre classifiers
-
Incorporation of Long Short Term Memory
-
Neural signals are time-series
- temporal importance
-
Neural signals are time-series
Ensemble Classifiers
Figures from Analytics Vidhya
Long Short Term Memory Networks
Figure from MDPI and ACS Style
Why Do We Care?
-
Memory Enhancement
- Cortical p-waves
-
Greater Understanding of Consolidation
- How do we improve learning?
- Neural basis of memory disorders
-
Post-Traumatic Stress Disorder
- Remove access to specific memories
Acknowledgments
Dr. Caleb Kemere
Shayok Dutta
PhD Candidate, Collaborator
Principal Investigator