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Optical imaging system for neurosurgery

  • US 5,215,095 A
  • Filed: 08/10/1990
  • Issued: 06/01/1993
  • Est. Priority Date: 08/10/1990
  • Status: Expired due to Term
First Claim
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1. Method for optically imaging neuronal activity of in vivo mammalian cortical areas comprising the steps of:

  • illuminating an in vivo cortical area of a mammalian brain with a regulated light source;

    focusing a magnification lens on said cortical area;

    detecting light reflected from said cortical area along a path through said magnification lens as an analog video signal representative of intrinsic signals, said intrinsic signals being generated in response to intrinsic characteristics of said cortical area;

    digitizing said detected analog video signal to provide at least one frame of digitized image data;

    acquiring and analyzing a plurality of frames of said digitized image data to identify changes in said intrinsic signals, said step of acquiring and analyzing further including the steps of;

    averaging a series of frames of said digital image data during a control period to provide a first averaged image frame, said control period being characterized by a substantial absence of input stimuli to the brain;

    storing said first averaged image frame;

    applying a predetermined input stimuli to the brain during a stimulation period;

    averaging a second series of frames of said digitized image data during said stimulation period to provide a second averaged image frame;

    storing said second averaged image frame;

    subtractively combining said first averaged image frame with said second averaged image frame to provide a first difference frame, said step of subtractively combining further including a step of spatially translating said first averaged image frame relative to said second averaged image frame;

    filtering said first difference frame to reduce noise;

    enhancing said first difference frame using a linear look-up table to stretch pixel values composing said difference frame;

    filtering said stretched difference frame;

    compressing and color-coding said difference frame; and

    ,superimposing an image of said color-coded difference frame upon a video image of said first or second averaged image frame to provide a composite image for identifying those portions of said cortical area subject to neuronal activity in response to said predetermined input stimuli.

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