Classification of prefrontal cortex activity based on functional near-infrared spectroscopy data upon olfactory stimulation

Cheng Hsuan Chen, Kuo Kai Shyu, Cheng Kai Lu, Chi Wen Jao, Po Lei Lee

Research output: Contribution to journalArticlepeer-review

2 Scopus citations


The sense of smell is one of the most important organs in humans, and olfactory imaging can detect signals in the anterior orbital frontal lobe. This study assessed olfactory stimuli using support vector machines (SVMs) with signals from functional near-infrared spectroscopy (fNIRS) data obtained from the prefrontal cortex. These data included odor stimuli and air state, which triggered the hemodynamic response function (HRF), determined from variations in oxyhemoglobin (oxyHb) and deoxyhemoglobin (deoxyHb) levels; photoplethysmography (PPG) of two wavelengths (raw optical red and near-infrared data); and the ratios of data from two optical datasets. We adopted three SVM kernel functions (i.e., linear, quadratic, and cubic) to analyze signals and compare their performance with the HRF and PPG signals. The results revealed that oxyHb yielded the most efficient single-signal data with a quadratic kernel function, and a combination of HRF and PPG signals yielded the most efficient multi-signal data with the cubic function. Our results revealed superior SVM analysis of HRFs for classifying odor and air status using fNIRS data during olfaction in humans. Furthermore, the olfactory stimulation can be accurately classified by using quadratic and cubic kernel functions in SVM, even for an individual participant data set.

Original languageEnglish
Article number701
JournalBrain Sciences
Issue number6
StatePublished - 2021


  • Classification
  • Functional near-infrared spectroscopy
  • Hemoglobin response function
  • Machine learning technique
  • Olfaction
  • Prefrontal cortex
  • Support vector machine


Dive into the research topics of 'Classification of prefrontal cortex activity based on functional near-infrared spectroscopy data upon olfactory stimulation'. Together they form a unique fingerprint.

Cite this