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. 2015 Winter;144(1):123-132.
doi: 10.1162/DAED_a_00321.

Consciousness

Terrence J Sejnowski  1
Affiliations

Consciousness

Terrence J Sejnowski. Daedalus. 2015 Winter.

Abstract

No one did more to draw neuroscientists' attention to the problem of consciousness in the twentieth century than Francis Crick, who may be better known as the co-discoverer (with James Watson) of the structure of DNA. Crick focused his research on visual awareness and based his analysis on the progress made over the last fifty years in uncovering the neural mechanisms underlying visual perception. Because much of what happens in our brains occurs below the level of consciousness and many of our intuitions about unconscious processing are misleading, consciousness remains an elusive problem. In the end, when all of the brain mechanisms that underlie consciousness have been identified, will we still be asking: "What is consciousness?" Or will the question shift, just as the question "What is life?" is no longer the same as it was before Francis Crick?

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Figures

Figure 1
Figure 1
Hierarchy of Visual Areas Visual information from retinal ganglion cells (rgc) in the retina project to the lateral geniculate nucleus (lgn) of the thalamus, whose relay cells project to the primary visual cortex (v1). The hierarchy of cortical areas terminates in the hippocampus (hc). Nearly all of the 187 links in the diagram are bidirectional, with feedforward connection from a lower area and feedback connection from the higher area. Source: Image courtesy of Henry Kennedy; based on Daniel J. Felleman and David C. Van Essen, “Distributed Hierarchical Processing in Primate Visual Cortex,” Cerebral Cortex 1 (1991): 1–47.
Figure 2
Figure 2
Flash-Lag Effect An object moves from left to right (top left). As it passes the center a light briefly flashes below it (top right). What subjects report is shown above: the object appears to be displaced to the right at the time of the flash. Source: http://hpcl.kde.yamaguchi-u.ac.jp/flashlag.html.
Figure 3
Figure 3
Visible and Hidden Search Tasks (A) An experienced pedestrian has prior knowledge of where to look for signs, cars, and sidewalks in this street scene. (B) Ducks foraging in a large expanse of grass. (C) A representation of the screen is superimposed with the hidden target distribution that is learned over the session as well as sample eye traces from three trials for participant M. The first fixation of each trial is marked with a black dot. The final and rewarded fixation is marked by a shaded grayscale dot. (D) The region of the screen sampled with fixation shrinks from the entire screen on early trials (light gray circles; first 5 trials) to a region that approximates the size and position of the Gaussian-integer distributed target locations (squares, darkness proportional to the probability as given in A) on later trials (circles; from trials 32–39). Source: Leanne Chukoskie, Joseph Snider, Michael C. Mozer, Richard J. Krauzlis, and Terrence J. Sejnowski, “Learning Where to Look for a Hidden Target,” Proceedings of the National Academy of Sciences 110 (2013): 10438–10445.
See this image and copyright information in PMC

References

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    1. There is no single accepted scientific definition of consciousness. However, it includes the state of being awake and aware of one’s surroundings, the awareness or perception of something, and the mind’s awareness of itself and the world.

    1. Crick Francis. private communication to Terrence J. Sejnowski. 1998.
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