Home > Soul > 16. How Sensory Inputs are Perceived

 

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Figure 16. The top panel, θ-γ, represents the oscillations where the γ oscillations are nested within the θ oscillation. An item is encoded by neuronal firing in a γ cycle. "A, B, C, D" represent different items within a θ cycle. This signal could be carried by GR waves through amplitude modulation. [Source: Zhang et al, 2016.]

The signals induced by sensory inputs are encoded in θ-γ nested oscillations (Figure 16). For instance, while playing tennis, you may see "a white ball moves rapidly along a direction." This visual input consists of four items: the ball's shape, color, moving direction and moving speed. Inside the brain, the input stimulates firing of a group of neurons. The information about an item is represented by the neuronal firing within a γ cycle. For simplicity, suppose the color is represented by only ten neurons. "0" and "1" denote the states of "resting" and "firing" respectively. In the same γ cycle, some neurons may be at rest while others are firing. Thus, the states of this group of neurons may represent the color information, such as:

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The signals induced by sensory inputs are carried by GR waves which travel at the speed of light unless they are bound by a geon. At this very moment, your eyes may be reading this article while certain sound may enter your ears. However, you do not perceive the sound if you are focused on this article. Attention to a sensory input occurs only when the input signal (encoded in the θ-γ modulated GR waves) is captured by a geon. In other words, conscious perception of a signal requires the binding of a geon with the GR waves carrying the signal.

Conscious perception of sensory inputs is analogous to the reception of television (TV) or radio signals. At any moment, all kinds of electromagnetic (EM) waves are passing through a TV or radio at the speed of light. When you tune in to a specific channel (corresponding to a particular station), only the EM waves transmitted from the particular station may be captured by a TV or radio, through "frequency resonance" between its electronic circuits and the EM waves. However, a geon does not use frequency resonance to capture signals. Instead, it employs synchronization, or constructive interference, to increase binding energy (see Chapter 13). This mechanism explains why the α frequency should be approximately twice the θ frequency (next chapter).