The 3D Default Space is mostly described in the 2014 paper and I have added some more quotes from the 2015 paper below. It is similar Global Workspace Theory and adds a 3D model which the thalamus creates by ‘re-imageing’ the sensory inputs into the 3D space. This is rich and detailed model that allows us to be conscious of the external world. The term "Default" refers to the Default Mode Network, one of the Resting State Networks.
To the right is an illustration of key components of the model by Lynsey Ekema
These are all quotes from the two papers until the very end.
“First we have designated the thalamus as a dynamic neural center that processes and integrates information from throughout the cortex and body to create a reimaging of 3D space.”
The lateral intraparietal area and medial intraparietal areas in monkeys can be equated to the ‘parietal eye field’ and ‘parietal reach region’ in humans respectively. Neurons in these areas represent visual space and remap this visual space when the eyes move, in a gaze-centered frame ...
the thalamus integrates and coordinates information from many different areas of the cortex. [ jch, how about synchronize active preconscious networks to oscillate together. -jch ]
an active electrical infrastructure likely supports visuospatial consciousness as well as body consciousness as a whole.
The entire body, bounded by our skin, forms the matrix for this 3D default space. All cells of the body are electrically charged, metabolically active, and interconnected. They originate from one cell and communicate via gap junctions interconnected by intracellular and extracellular fluid (Lampe & Lau, 2004). The entire body of cells constitutes a frame- work that serves as a 3D default matrix on which the 3D default space and all internal and external memories are formed. The thalamus seamlessly reimages or projects processed visual and non-visual information within this space. When we refer to ‘‘reimaging’’ we mean the integration and subsequent representation of visual and non-visual information in the sensory apparatus within the mind. We propose that this reimaging is done by parallel processing throughout the cortex that is integrated by the reticular nucleus and other nuclei of the thalamus. the thalamus may regulate cortical activity by way of phase-amplitude coupling, which may be the mechanism by which information is integrated and segregated across cortical areas.
3D Default Space Theory:
Sensory information is converted into electrical signals at the sensory end organ which is then integrated and filled-in within the 3D default space. We propose that the outside world is recreated internally in a format that is optimal for interacting with and responding to the external environment. However, both attention processes and memory contribute to the final representation within and experience of conscious events. Processed external and internal stimuli are recreated within this dynamic and active sensory memory space in which current conscious experience, dreaming, and recollection of memories takes place. Our consciousness model includes components from the GW theory such as the important role of corticothalamic processing. However, in our model, corticothalamic feedback loops process sensory information from throughout the body and this information is then integrated by the thalamus and filled in to the 3D default space (Jerath and Crawford, 2014)
We propose that conscious experience arises when this space is filled in by input from the thalamus, as opposed to the GW theory in which consciousness can arise anywhere throughout the cortex. This 3D default space is home to a neural global workplace in which external space is represented internally (Figure 2). The human body consists of intrapersonal space that is composed of all the interconnected cells of the body, which are all connected and communicate via gap junctions and electrical potentials (Saez et al., 2003); we have termed this the 3D default space.
- Multisensory integration is primarily an unconscious process, as opposed to other models that propose consciousness is needed for multisensory integration.
- As other consciousness models have proposed, frontoparietal networks are important for consciousness; however, we propose that information processed by these networks must be sent back and integrated by the thalamus to rise to conscious awareness.
(Merker, 2007) has discussed the possible role of thalamic nuclei in implementing a “global best estimate buffer” and implementing perspective and an ego-center for interactions with the body and external world (Merker, 2012).
Attention and consciousness are highly related and some researchers even equate the two but these processes should not be considered one and the same (Koch and Tsuchiya, 2007). This can be illustrated by the fact that subjects can be aware of an object without input from top-down attention processes and subjects can attend to objects they are not consciously aware of (Koch and Tsuchiya, 2007). Both the Global Workspace Theory and our model emphasize the important role of working memory in consciousness. Memory and attention both play important roles in constructing moment to moment experiences within the active sensory memory space. Attention processes and memory input are integrated with processed incoming sensory information to fill in the sensory memory space. Although conscious experience appears to be seamless, many studies have shown that information processing is likely done in distinct snapshots, similar to a movie reel that is made up of separate images (Marchetti, 2014).
This solves the "Pin the Tail on the Donkey Problem." (Hardenbergh 2018) How can we close our eyes, walk across the room and pin the tail on the donkey - nearly exactly. That's why we need to turn kids around until they are dizzy.
It does not make sense that the thalamus itself is integrating information, since there are no data lines between the senses in the thalamus., Rather, the little bundle of nuclei forms an electric field that can synchronize multiple preconscious networks. What do you think?
Also, must the Thalamus be the mechanism of the 3D model? Feinberg and Mallet make a strong case for the Optic Tectum being the original seat of the model of the world that enables consciousness in the book Ancient Origins of Consciousness: How the Brain Created Experience.
Lots of talk of integrating the vsicera, etc into consciousness, but, no mention of the Vagus Nerve
Perhaps I am getting confused about the model itself versus the hardware/software platform that embodies the model.
The 2015 paper is as rich and rewarding as Baars et al 2013, but, like that paper, it seems to get off topic in places.
It says to me that we are projecting a 3D mental model of the world into a spatiotopic space within our mind. But, is that what you are really saying? I get confused by the default 3D space getting conflated with the whole body. "3D default space consists of the entire brain and body and all the communicating cells within."
[ ? only a partial disruption of the pathways responsible for visuospatial processing. ]
It says to me that we are projecting a 3D mental model of the world into a spatiotopic space within our mind.
I think the central idea is brilliant - "This idling brain activity may provide the foundation for an active space that is filled-in by the thalamus. We propose that external and internal sensory information is processed by corticothalamic feedback loops and projected by the thalamus within a proposed 3D default space, recreating the external world within the mind.”
jch.com/jch/notes/Jerath3D2014.html 2017-02-16 YON Book Notes