Spontaneous multichannel brain electric field (EEG) map series of 20 seconds duration at 1, 15, 30, 45, and 60 minutes after the injection of a single dose of diazepam (13 ss) or sulpiride (6 ss) were segmented into microstates of quasi-constant landscape but varying durations. Post-minus-preinjection difference values were computed for the six microstate variables: specific window size, duration, orientation, distance between windows, and location of center of gravity on the anterior-posterior and left-right axis. Differences between drugs were explored with ANOVAs. Microstate duration increased after sulpiride, and the location of the microstate center of gravity on the anterior-posterior axis moved to a more anterior position after diazepam. The results are in agreement with expectations based on measurements of patients' EEG microstates and with results using estimates of EEG model source locations in the frequency domain. Microstate segmentation appears to be a useful method for physiologically meaningful reduction of multichannel brain electric field data in psychopharmacology.

A variable-bit-rate high-definition television (HDTV) coding algorithm based on motion-adaptive, discrete cosine transform (DCT) is investigated for asynchronous transfer mode (ATM) environments in broadband integrated-services digital networks (B-ISDN). The proposed algorithm effectively reduces the bit rate, in particular, for HDTV-picture sources with little motion. Adaptive two-layered coding, an ATM cell matrix for error correction, and a block interleave for error concealment are proposed to keep picture quality high by compensating for ATM cell loss. A new feed-fomard control scheme for variable-length coding (VLC), a multimode quantization that restricts peak bit rate and average bit rate, is also proposed for traffic control. Experimental hardware is shown to reduce the coding bit rate for pictures of HDTV conference applications to peak bit rate of 65 Mb/s and an average bit rate of 10-20 Mb / s in ATM environments.

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