Changes in Phase Amplitude Coupling in TreatmentResistant Depression

Changes in Phase Amplitude Coupling in Treatment-Resistant Depression (TRD) due to Deep Brain Stimulation(DBS) Presentation for IEEE EMBS Rehman Ali

What is Phase Amplitude Coupling (PAC)? • Type of Cross-Frequency Coupling (CFC) • Between a low frequency and a high frequency oscillation • Analyzed between the phase of the low frequency oscillation and the amplitude envelope of the high frequency oscillation • Theorized to play a functional role in neural oscillations: • Low frequency oscillations over a large region modulating high frequency oscillations over a smaller population of neurons • High-frequency power may be activated along a low-frequency phase

Why PAC? • To explore palliative effects of DBS • Shown to play an important role in DBS of Parkinson’s disease: • PAC between Beta phase and Gamma amplitude at Subthalamic Nucleus and Motor Cortex decreases with DBS. • Aberrant PAC demonstrates possible mechanism by which DBS alleviates Parkinson’s disease • We want to do the same with TRD • Subcallosal Cingulate is site of DBS • Heterogenous Patient Population: Only criteria for TRD is failure of four otherapeutic approaches de Hemptinne C, Ryapolova-Webb ES, Air EL, Garcia PA, Miller KJ, Ojemann JG, Ostrem JL, Galifianakis NB, Starr PA (2013) Exaggerated phase-amplitude coupling in the primary motor cortex in Parkinson disease. Proc Natl Acad Sci U S A 110: 4780 -4785.

General Algorithm for PAC Detection

Electrical Engineering Challenges • Band-Pass Filters Design • Bandwidth of the band-pass filter • Shape of band-pass filter • Correlational Metrics PAC • • All are imperfect/incomplete Best to use every kind possible Transient vs. Stationary Coupling Comparative investigation ongoing: • Validation: Need Synthetic Signals • How to generate Synthetic Signals? • How to compare? • Future: real-time comodulograms • Hardware optimized to algorithms and vice-versa for real-time computing on GPUs • Convenient for clinical neurology Berman JI, Mc. Daniel J, Liu S, Cornew L, Gaetz W, Roberts TP, Edgar JC (2012) Variable bandwidth filtering for improved sensitivity of cross-frequency coupling metrics. Brain connectivity 2: 155 -163.

QUESTIONS ?

SUPPLEMENTARY INFORMATION FOLLOWING SLIDES

Classification of Brain Oscillations • Source: http: //salvonostrato. com/wp/01 -b-c-s-m-j-p-a

Basic Neuroanatomy for Parkinson’s Disease • Source: http: //en. wikipedia. org/wiki/Motor_cortex • Source: http: //editthis. info/psy 3242/Basal_ganglia

Subcallosal Cingulate for DBS of TRD • Subcallosal Cingulate Gyrus • Subgenual Cingulate • Brodmann Area 25 Source: http: //en. wikipedia. org/wiki/Cingulate_cortex