Watching the movie

As everyone knows, even little children, moving pictures do not move. They are a series of very still pictures. But we make a movie from them in our brain. The question is how.

Surprisingly, sometimes we don’t. Some people with migraines have periods of ‘cinematographic vision’. It is like a movie run too slow so that there is the effect of little jumps between frames. The sufferers are not making the normal movement-effect in their perception.

So – maybe we do the movie trick all the time. Maybe our visual perception is a series of still pictures that are then made into a movie for our consciousness. 

When I went looking for info on this subject I happened on a paper by Walter J Freeman, A Cinematographic Hypothesis of Cortical Dynamics in Perception, University of California, Postprints 2006. It is not an easy paper for someone outside that specialty to read.  (found here) . Using EEG methods and sophisticated analysis, he was able classify spatial and temporal patterns. The abstract is below.

“The aim of this study was to measure and classify spatial patterns in sensory cortical EEGs relating to conditioned stimuli (CSs) in order to test the hypothesis, based on clinical reports, that cortical dynamics is not continuous but operates in steps that resemble frames in a cinema. Recent advances in the application of the Hilbert Transform to intracranial recordings of the EEG in animals have revealed markers for repetitive phase transitions in neo-cortex at frame rates in the theta band…The impact of a CS on a sensory neo-cortex reorganized background EEG into two types of sequential patterns of coordinated activity, initially local and modality-specific, later global. The initial stage of phase transitions required 3-7ms. Large-scale cortical activity then reorganized itself repeatedly and reliably over relatively immense cortical distances within the cycle duration of the center frequency of oscillation. The size, texture, timing and duration of the amplitude modulation patterns support the hypothesis that these frames may provide the basis for multi-sensory percepts.”

The paper identifies a phase transition that is localized to the primary sensory area with a carrier frequency in the gamma band and recurrence rates in the theta band (gamma packets). The later phase transitions that involve many sensory areas have carrier frequencies in the beta band (beta packets) and recurrence rates in the theta band. The activity is not continuous but in demarcated discontinuous patterns.

Another report that caught my eye was Working Memory Has Limited ‘Slots’ Science Daily Apr 7 2008 reporting work by Luck and Zhang. (here) 

Humans rarely move their eyes smoothly. As our eyes flit from object to object, the visual system briefly shuts off to cut down visual “noise,” said Steven J. Luck, professor of psychology at the UC Davis Center for Mind and Brain. So the brain gets a series of snapshots of about a quarter-second, separated by brief gaps… The working memory system smooths out this jerky sequence of images by retaining memories from each snapshot so that they can be blended together. These memories typically last just a few seconds, Luck said.

If the memory of our consciousness is individual frames then it is not unreasonable that the original consciousness was too. It takes time to create a perceptual model and when it is complete, it is stored. The creation of the next iteration of the model can then start. There is a process that morphs one into the next to give an impression of continuous movement.

This entry was posted on 19/07/2008 at 03:09 pm and is filed under timing. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response or trackback from your own site.