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Modeling the Evolution of Neurophysiological Signals. Mark Fiecas Hernando Ombao. Data Characteristics. Small signal-to-noise ratios. Data Characteristics. Nonstationary time series data. Data Characteristics. Evolving over time within a replicate
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Modeling the Evolution of Neurophysiological Signals Mark Fiecas Hernando Ombao
Data Characteristics Small signal-to-noise ratios
Data Characteristics Nonstationarytime series data
Data Characteristics Evolving over time within a replicate Nonidentical replicates across the experiment
The Time Series Models Weakly stationary time series (Brillinger, 1981):
The Time Series Models Locally stationary time series (Dahlhaus, 2000):
The Time Series Models Locally stationary time series with slowly evolving replicates:
The Time Series Models • Replicates are uncorrelated. For each replicate, use existing methods to address nonstationarity over time. • Smooth the estimates over time and replicate-time.
A Relevant Scientific Question Is the power in a frequency band of interest the same between “familiar” and “novel” trials?
Log Periodogram Models Weakly stationary data (Krafty et al, 2011):
Log Periodogram Models Weakly stationary data (Krafty et al, 2011):where
The Log Periodogram Models Locally stationary data (Krafty, 2007; Qin and Guo, 2009):
The Log Periodogram Models Locally stationary data (Krafty et al, 2007):where
Calling All Statisticians “Understanding how the brain works is arguably one of the greatest scientific challenges of our time.” - Alivisatos et al, 2013
Calling All Statisticians • The BRAIN Initiative (USA) • The Human Brain Project (European Union) • 86 Institutions in Europe involved • €1 billion in funding / year
Calling All Statisticians Very rich data sets • High temporal resolution (EEG, MEG, LFP) • High spatial resolution (PET, fMRI) • 300k spatial locations in fMRI • Imaging genetics Many open problems
Calling All Statisticians Handbook of Modern Statistical Methods: Neuroimaging Data Analysis (eds: H. Ombao, M. Lindquist, W. Thompson, and J. Aston)
Acknowledgments • Shaun Patel, Boston University • EmadEskandar, MGH