**3. Assumptions for the neuroFunctional Model of Consciousness (nFMC)**


*Connectivity and Functional Specialization in the Brain*

desires, and/or thoughts [6, 139].

**2.3 C-C neural loop**

cognitive processes [160].

functional conscious state of the individual [163].

activation that will trigger awareness [137]. The conscious perception of the content of consciousness is the end of the concatenation of neurophysiological events that propagate from the back to the front cortex [6, 138]. It would be like a competition among various neural coalitions to access consciousness, and once a winning coalition exists (the first to break neurophysiological requirements), a specific representation or the content of consciousness can be perceived as generating a genuine experience of consciousness [137]. Afterward, this content of consciousness is controlled by high-order cognitive functions and is incorporated into plans,

Once the content of consciousness is created in the back brain [132, 133], various cortico-cortical networks consciously manipulate the information [140]. One of the main cortico-cortical networks, which is broadly documented, is the Default Mode Network (DMN) [141–144]. This network is formed by the anterior and posterior cingulate cortex, the mPFC, the orbital PFC, the medial temporal lobe (parahippocampal cortex and HPC), the retrosplenial cortex, and the inferior parietal lobe [145] . The DMN is a rest neural network, whose activity is maximum when the subject is awake and the cognitive demand is low (low-level processing of exogenous information) [146]. Moreover, the DMN is characterized by a high metabolism during rest states [147–150], a progressive deactivation when more cognitive resources are needed to process information [147], and a high connectivity with other cortico-cortical networks to exchange information [140, 143, 151]. Traditionally, the DMN has been related to internal processes, such as self-reference thoughts and mind-wandering [152–154], although some studies currently link its activity to extrinsic processes, such as certain attentional processes [155] and the recall of memories [156–159]. Recently, it has been posed that the DMN could also be involved in the integration of spatial, selfreference, and temporal information, thus generating episodic memories [160]. These authors suggest that, henceforth, the DMN is mostly activated in all of the

One of the key points for understanding the role of the DMN in consciousness is to conceive it as a cognitive system that modulate cortico-cortical activity through its mediation in the transfer of information from resting states or task-negative networks to cognitively active states or task-positive networks [140, 147, 156, 161–164]. When a subject is resting (with the low-level processing of exogenous information), the DMN controls cortical activity with the posterior cingulate cortex (PCC) and the precuneus (Pcu) as their main neural nodes. However, as long as elaborated processing is required and the load of the working memory increases, the physiological burden of the DMN decreases in favor of task-positive networks: the fronto-parietal central executive network (FPN), the dorsal attention network (DAN), and the salience network (SN). The FPN includes the dorsolateral PFC, the mPFC, the anterior insula (aINS), the Pcu, and the interior parietal lobe [140, 165–167]. On the other hand, the DAN is formed by the frontal eye field and the intraparietal sulcus [168], and the SN by the aINS, the dorsal anterior cingulate cortex, the amygdala, the ventral striatum, and the ventral tegmental area of the mesencephalon [169]. All of these networks share overlapping regions whereby they can exchange neural information depending on the ongoing cognitive activity [147, 149, 150, 170–173] . The outcome of the continuous interactions among the cortico-cortical networks will define the

The FPN, DAN, and SN play a key role in conscious behavior due to its capacity to operate jointly and synchronically in a highly coordinated and temporally

**122**

#### **Figure 1.**

*Consciousness is the phenomenological quality of human existence that arises from a hierarchical, parallel, and serial activation of long-distance brain networks [7], which operate as neural loops that "inform" upper and lower levels about their own operations [29, 30]. These loops receive input from lower levels (which contains new information/predictions) and input from upper levels (error predictions). The loop will integrate all of this new information, updating its own functional state and, consequently, also the functional state of the rest of the loops and the brain [29–32, 191]. ARAS: Ascending reticular activating system; TNN: Task-negative networks; TPN: Task-positive networks.*


**125**

*The Neurofunctional Model of Consciousness: The Physiological Interconnectivity of Brain…*

via bottom–up processing, and where higher cortical areas send prediction er-

8.The nFMC is complementary and comprises several assumptions considered in

• Consciousness can be deemed a Global Neural Workspace in which distinct

• Consciousness is the result of functional units or complexes that integrate information and that are activated or deactivated depending on the ongoing

• Consciousness is a neurophysiological continuum commanded by inner

9.Regarding the neural mechanisms or processes involved in the formation of the content of consciousness, the nFMC aligns with models and evidence that posit that the contents of consciousness are formed in the back brain via cortico-thalamo-cortical connections [70, 132–136]. In addition, the nFMC recognizes that PFC top-down connections could modulate the selection and

Human behavior has to be understood as a global brain activity dominated by complex and hierarchical neural processes that cannot be divided and explained by isolated functional units. Consciousness is the "operating system" running underneath the "interface" of overt and covert human behavior, and it is dominated by the interactions of various neural levels composed of differentiated and semi-independent neural networks. Thence, the nFMC gathers reliable knowledge generated in the study on neural correlates of consciousness, providing a novel theoretical and referential framework that will help clinicians, researchers, and even students to localize the neural processes of interest within a global brain activity model. A further proposal should extend the structures and connectivity

neural networks compete to access consciousness [11, 25, 192].

previous theories and investigations of consciousness:

even the formation of the content of consciousness [28].

involved within and between each neural loop introduced in the nFMC.

The authors have no conflict of interest to declare.

sensorial/visceral necessities [8, 26, 27].

spatio-temporal brain laws [6].

**4. Conclusion**

**Conflict of interest**

7.Neural processes (both automatic and controlled) related to consciousness (such as P300, brain rhythms, and neurotransmitter discharges) can be localized within either of the neural loops or in their reciprocal interactions.

*DOI: http://dx.doi.org/10.5772/intechopen.94221*

rors back via top-down processes.

via bottom–up processing, and where higher cortical areas send prediction errors back via top-down processes.

	- Consciousness can be deemed a Global Neural Workspace in which distinct neural networks compete to access consciousness [11, 25, 192].
	- Consciousness is the result of functional units or complexes that integrate information and that are activated or deactivated depending on the ongoing sensorial/visceral necessities [8, 26, 27].
	- Consciousness is a neurophysiological continuum commanded by inner spatio-temporal brain laws [6].
