Parallel visual pathways and face perception

Shozo Tobimatsu

    Research output: Chapter in Book/Report/Conference proceedingConference contribution


    There are two major parallel pathways in humans: the parvocellular (P) and magnocellular (M) pathways. The former has excellent spatial resolution with color selectivity while the latter shows excellent temporal resolution with high contrast sensitivity. Visual stimuli should be tailored to answer specific clinical and/or research questions. We examined the neural mechanisms of face perception using event-related potentials (ERPs). Face stimuli of different spatial frequencies were used to investigate how low-spatial-frequency (LSF) and high-spatial-frequency (HSF) components of the face contribute to the identification and recognition of the face and facial expressions. The P100 in the occipital area (Oz), N170 in the posterior temporal region (T5/T6) and late components peaking at 270-390 ms (T5/T6) were analyzed. LSF enhanced P100 while N170 was augmented by HSF irrespective of facial expressions, which suggests that LSF is important for global processing for face whereas HSF handles featural processing. There were significant amplitude differences between positive and negative LSF facial expressions in the early time windows of 270-310 ms. Subsequently, the amplitudes among negative HSF facial expressions differed significantly in the later time windows of 330-390 ms. Discrimination between positive and negative facial expressions precedes discrimination among different negative expressions in a sequential manner based on parallel visual channels. Interestingly, patients with schizophrenia showed decreased spatial frequency sensitivities for face processing. Taken together, our spatially filtered face images are useful for exploring the face perception and recognition.

    Original languageEnglish
    Title of host publication2010 IEEE/ICME International Conference on Complex Medical Engineering, CME2010
    Number of pages4
    Publication statusPublished - 2010
    Event2010 IEEE/ICME International Conference on Complex Medical Engineering, CME2010 - Gold Coast, QLD, Australia
    Duration: Jul 13 2010Jul 15 2010

    Publication series

    Name2010 IEEE/ICME International Conference on Complex Medical Engineering, CME2010


    Other2010 IEEE/ICME International Conference on Complex Medical Engineering, CME2010
    CityGold Coast, QLD

    All Science Journal Classification (ASJC) codes

    • Biomedical Engineering
    • Radiology Nuclear Medicine and imaging
    • General Neuroscience


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