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Online models for real-time operations planning face a host of implementation issues that do not arise in more strategic arenas. We use the seemingly simple problem of assigning drivers to loads in the truckload motor carrier industry as an instance to study the issues that arise in the process of implementing a real-time dispatch system. Although the project was moderately successful, our focus is not on documenting the benefits, but rather on summarizing the challenges that arose. The most significant theme running through the implementation hurdles we encountered was the lack of information available to the model. Computers are very good at processing vast quantities of information; humans are very good at challenging the information that is in the computer and augmenting computer-provided data with head knowledge. Our study includes a careful comparison of actual decisions with model recommendations, using a six-month database of actual transactions. This comparison is the first we have seen of its kind and provides the most rigorous evaluation of an online dispatch model that we have seen. Although the model was well used, the results demonstrate that significant improvements could have been obtained if the level of model utilization had been even higher.

The responses of somatosensory cortex (S-I) to tactile stimulation of the forepaw were assessed by intrinsic signal optical imaging. The tips of digits two or five were alternately touched with mechanical tappers while video photographs were taken of S-I illuminated by an 800-nm light source. The resulting images showed two hilighted areas about 300 zm in diameter and 500 ,um apart. Generation of these images required <1 hr. Electrode penetrations placed in the areas highlighted during stimulation provided multiunit recordings with receptive fields appropriate for the stimulated digit and not the other digit. Penetrations between the highlighted areas yielded receptive fields on intervening digits. These results demonstrate that intrinsic signal optical images are obtainable in S-I and confirm the functional somatotopy previously reported using electrical recording. Furthermore, the short time required to produce the images and the obtainable spatial resolution suggest that optical recording could be employed for the study of cortical reorganization in this brain region.Optical imaging provides a means of studying the activity of regions of the cerebral cortex over time and space. The method produces a neural-activity-dependent image through the use of a video camera. Optical recording is similar to the 2-deoxyglucose method in that an image related to neural

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