Scientific Understanding of Consciousness
Consciousness as an Emergent Property of Thalamocortical Activity

Mental Image, Map, Neural Pattern, Image, Object, etc.

Consciousness is the images (and thoughts and feelings) that are represented in activated neural networks. (Hobson; Consciousness, 141)

Temporally coordinated activity of varied early cortices and of the subcortical stations with which they are interconnected yields the essence of what we call an image.(Damasio; Making Images, 20)

No actual image in the brain;    "image" is a correlation between different kinds of categorizations. (Edelman; Bright Air, 117)

The firing rates of sparse but widely separated populations of neurons carries the information representing a mental image. No particular set of neurons is required. The neural assembly is slightly different each time the mental image is constructed. The pattern of active synapses in millions of dendritic trees is similar but never identical each time the image is constructed. In all likelihood, I suspect a small portion of individual neurons may "flicker on and off" near the threshold of conduction even while an active image dynamically exists.

Consciousness a Convolution of the Perceptual Mental Image with the Sense-of-Self

Many Words and Terms Referring to Similar Concepts

Consciousness literature contains many words and terms referring to similar concepts related to “mental image.” In general, thalamocortical activity, supported by subcortical activity, mediates a neural representation of a worldly object or concept, either perceived or imagined. This momentarily ‘mental image’ representing a thought is ‘convolved with’ the neural representation of ‘the self’ to yield core consciousness.

As the science of consciousness matures, the terms and definitions will coalesce and become more explicit. Some researchers have informally defined technical meanings to certain English words and phrases. I’ll list several of these words and terms here: [categorization, concept, ENGRAM, idea, image, map, MEMORY, mental image, MENTAL OBJECT, neural image, neural map, neural pattern, OBJECT, percept, perception, perceptual categorization], and the list probably could go on. I’ll use these and other terms and hope the context will make the meaning clear.

Engrams (Wikipedia) are means by which memory traces are stored as biophysical or biochemical changes in the synapses and dendritic trees of neurons.

 

Neural Maps and Topographical Patterns

The terms ‘map’, ‘mapping’, ‘neural map’ deserve special comment. Nerves of the somatosensory system are mapped in the cortex in a topographical pattern corresponding to areas on the skin. The term ‘map’ accurately describes the biological fact of this relationship. Other similar terms such as ‘global mapping’ are simply extensions of this somatosensory mapping idea. Hierarchical assemblies of auditory, visual and other neural maps, including both cortical and subcortical, are considered global maps. The hierarchical assemblies are processed via Damasio’s convergence-divergence zones architecture.

An important characteristic of images is that they have spatially and temporally organized patterns, and in the case of visual, somatosensory, and auditory images, those patterns are topographically organized. (Damasio; Making Images, 20)

Topographic representations can arise in turn as a result of signals external to the brain in the perceptual process, or in the process of recall from signals inside the brain, coming from memory records held in dispositional representation form. (Damasio; Making Images, 20)

 

The Self -- Entire Neural Network Represents a Person's Individuality and Personality

A person's individuality and personality are represented in the Self, a neural network of synaptic efficacies established by genetics and a lifetime of neural activity experienced in the environment. The synapses have short-term plasticity via biochemical changes and longer-term plasticity over weeks and longer via (consolidation) gene expression and protein synthesis.

The self is comprised of the nervous system’s entire ensemble of synapses representing genetic endowment together with life experiences (encrusted/ingrained/embedded/inscribed/imprinted/embossed) in synaptic patterns,  The sense-of-self contributing to a momentary dynamic core of consciousness arises from the neural activity pattern in a portion of the network.

Neural Patterns (map) and Mental Images

Because words such as images, neural patterns, representations, and maps have various connotations, their use if fraught with difficulties. Nonetheless such words are indispensable to convey thoughts in any attempt to deal with the topics of consciousness. Damasio uses images as a synonym for mental images. Mental images are the mental constructs we normally experience in consciousness. Neural patterns or neural maps or maps are the neural representation of the mental images. (Damasio, Feeling of What Happens, 317)

Patterns of neural signal traces in the dendritic trees of neurons, dynamically connected momentarily by efficacious synapses, sculptured by genetics and experience, mediate neural network activity, an ever-changing subset of which forms the dynamic core of consciousness.

Consciousness is a ‘convolution’ of a current perceptual image (engram) with a neural network image of the sense of self.

 

Let us assume that the persistence or repetition of a reverberatory activity (or "trace") tends to induce lasting cellular changes that add to its stability. (Hebb; Organization of Behavior, 60)

Cerebral cortex is arranged as a set of maps, which receive inputs via the thalamus. (Edelman; Bright Air, 117)

Global mappings are dynamic systems consisting of multiple reentrant local maps that correlate sensory input with motor activity. (Edelman, Remembered Present, 121)      Perception-Action cycle of Fuster.

Both organism and object are mapped as neural patterns in the first-order maps; all of these neural patterns can become images. Second-order maps represent the relationship of object and organism. (Damasio, Feeling of What Happens, 317)

Neural patterns transiently formed in second-order maps can become mental images. (Damasio, Feeling of What Happens, 169)

Humor is what happens when an assumption is epistemically committed to in a mental space and then discovered to have been a mistake. (Hurley, Dennett, Adams; Inside Jokes, 121)

 

Mental image

Mental image is an autonomous and transient memory object, not requiring direct interaction with the environment. (Changeux, Neuronal Man, 138)

An important characteristic of images is that they have spatially and temporally organized patterns, and in the case of visual, somatosensory, and auditory images, those patterns are topographically organized. (Damasio; Making Images, 20)

Image - Mental image - reentrant connection of the value-category memory to cortical systems carrying out perceptual categorizations. (Edelman, Remembered Present, 101)

Humans experience primary [core] consciousness as a "picture" or "mental image" of ongoing categorized events. No actual image in the brain; "image" is a correlation between different kinds of categorizations. (Edelman; Bright Air, 119)

Consciousness can be focused on an internalized representation, such as a hope or a memory. (Greenfield; Centers of Mind, 91)

When we interact with an object outside ourselves, the image we experience is based on changes that occur in our organism -- including the brain -- when the physical structure of the object interacts with the body. Sensors located throughout the body -- in the skin, in the muscles, in the retina, and so on -- help construct the neural patterns that map the organism's interaction with the object. The neural pattern (map) is based on the momentary selection of neurons and circuits engaged in the interaction. (Damasio, Feeling of What Happens, 320)

 

Brain makes images

The brain operates as a reality emulator. (Llinás; I of the Vortex, 13)

The brain fashions an internal model of the external world as a basis for prediction and exploration of alternatives. (Holland; Hidden Order, 33)

Our brains are belief engines, evolved pattern recognition machines that connect the dots and create meaning out of the patterns that we think we see in nature. (Shermer; Believing Brain, 59)

Early sensory cortices are the critical base for processes of image making. (Damasio; Making Images, 20)

Damage to higher-order association cortices, which are located outside of the early sensory region, does not preclude the making of images. (Damasio; Making Images, 20)

Hypothesized that the early sensory cortices of each modality construct, with the assistance of structures in the thalamus and the colliculi, neural representations that are the basis for images. (Damasio; Making Images, 20)

Temporally coordinated activity of varied early cortices and of the subcortical stations with which they are interconnected yields the essence of what we call an image. (Damasio; Making Images, 20)

 

 

Mental Object or Neural Pattern

Mental object is identified as the physical state created by correlated, transient activity, both electrical and chemical, in a large population or 'assembly' of neurons in several specific cortical areas. (Changeux, Neuronal Man, 137)

Object is used in a broad and abstract sense -- a person, a place, a pain, an emotion. Neural events at the molecular, cellular, and systems levels contribute to the neural patterns (maps) that result in our mental images that create the mind. (Damasio, Feeling of What Happens, , 323)

Impairment of image making with one sensory modality, e.g., visual or auditory, only compromises the conscious appreciation of one aspect of an object. (Damasio, Feeling of What Happens, 123)

Impairment of all image-making capability abolishes consciousness altogether because consciousness operates on images. (Damasio, Feeling of What Happens, 123)

 

Perceptual Categorization

Perceptual categorization -- the ability to carve up the world of signals into categories adaptive for a given animal species. Along with control of movement, perceptual categorization is the most fundamental process of the vertebrate nervous system. (Edelman, Universe of Consciousness, 102-104)

Images can be completely internal as when dreaming

 

Concepts

Concept -- the ability to combine different perceptual categorizations related to a scene or an object and to construct a "universal" reflecting the abstraction of some common feature across a variety of such percepts. Concepts arise as a result of the mapping by the brain itself of the activity of the brain's different areas and regions. Various common features of responses to different signals can be abstracted. Forward motion is a concept. (Edelman, Universe of Consciousness, 102-104)

A 'concept' is a memory object that contains only a small sensory component, because it is the result of neuronal activity in association areas such as the frontal lobe (where multiple sensory or motor modalities are mixed) or in a large number of areas in different regions of the brain. (Changeux; Neuronal Man, 138)

 

Ideas

An idea is a mental image that has been freed from fixed, immediate action.  Humans can form an image that is less tied to action and therefore can acquire a new meaning and symbolism. Once an image is separated from its action, that image can serve a new  purpose: to plan, solve problems, and think. (Greenspan; First Idea, 37)

Art

Art is humans' attempt to express their internal model of reality, a model representing their emotional state, cognitive state, and fictive state.

Music stimulates an emotional state. In listening to music by Beethoven, I typically feel as though I'm communicating with the mind of Beethoven.

Art is the language and medium for communicating between the mind of the artist and the mind of the human observer.

 

 

Return to — Esoteric Terms and Concepts

Link to — Consciousness Subject Outline

Further discussion — Covington Theory of Consciousness