See Also: Book Notes, Notes on Consciousness, Consciousness and the Brain, Consciousness: Confessions, The Quest for Consciousness, Happiness Hypothesis

The Body Model Theory of Somatosensory Cortex

Michael Brecht <> <> PDF <> italics means direct quote

Theory of somatosensory cortex as a body model serving both for body representation and ‘‘body simulation.’’ A modular model of innervated and non-innervated body parts resides in somatosensory cortical layer 4. This body model is continuously updated and compares to an avatar (an animatable puppet) rather than a mere sensory map. Superficial layers provide context and store sensory memories, whereas layer 5 provides motor output and stores motor memories. I predict that layer-6-to-layer-4 inputs initiate body simulations allowing rehearsal and risk assessment of difficult actions, such as jumps.

Cognitive Modeling versus Predictive Coding

"The functions of the body model in body simulation suggested here, however, go well beyond mere prediction in motor control."

Body Modeling does not need the comparison mechanism, so the architecture can be much more flexible.

Primate primary somatosensory cortex contains not one but four somatosensory areas (area 3a, area 3b, area 2, and area 1). I expect that each of these areas generates a slightly different body model—a more cutaneous one in area 3b and a more muscle-oriented one in area 1—but that activity in these areas is tightly coordinated.

animatable puppet, aka marionette or string puppet (Pinocchio). This is exactly what proprioceptive means!

Need Layers diagram! (superficial) Good one here:

The prediction model runs at 10Hz -

"In line with the idea that the embodiment operation, which shapes the layer 4 body model, operates on slow timescales,"

Body Simulation

"Specifically, I predict body simulations prior to jumps, beam walking, etc."

Dick Fosbury articulated this early on: "Then I developed a thought process in order to repeat a successful jump: I would 'psyche' myself up; create a picture; 'feel' a successful jump--the perfect jump; and develop a positive attitude to make the jump. My success came from the visualization and imaging process."

The rubber hand illusion challenges the naive view that body perception is something given by somatosensory afferents. Instead, the data suggest body perception is dynamical and depends on the multisensory interpretation of the world.

More than just Theory of Mind: "These findings reiterate the idea that we use a mental body model in social contexts for modeling other people."

How does this related to 3D Default Space? 2018-09-15 jch