I applaud Morsella et al.'s approach to investigate consciousness in terms of behavioral control. After all, the function of the brain is to control behavior, and consciousness contributes to the function of the brain. However, I question whether conscious content is available only to the skeletal muscle system, as the principle of parallel responses into skeletal muscle (PRISM) (Morsella 2005) proposes.

The central nervous system (CNS) evolved from a chemosensory epithelium, but a simple epithelium has limited means to resolve conflicts between early drives (e.g., approach vs. avoid). Understanding the role of “consciousness” as a resolution device, with specific focus on chemosensation and the olfactory system, is of appeal. I argue that consciousness is not the adjudicator, but is instead the forum that brings conflicting (conscious) inputs into a form that allows them to be (unconsciously) compared/contrasted, guiding rational action.

I argue that the scope and strength of unconscious perception have been overestimated in extant theories. I describe an unconscious binding perspective, and how in conjunction with rigorous methodology it can guide the delineation of unconscious processing. Under this perspective, the function of consciousness is to increase the saliency of conscious contents by facilitating the deployment of focal attention.

What is consciousness for? Consciousness allows us to handle conflict, a promising proposal by Morsella et al. However, they provide little evidence as to why consciousness is particularly valuable in resolving conflict, nor do they limit the role of consciousness to only conflicting experiences. We attempt to clarify their possible positions and offer several solutions for how these might be formulated and tested.

While the field of emotions research has benefited from new developments in neuroscience, many theoretical questions remain unsolved. We propose that integrating our iterative reprocessing (IR) framework with the passive frame theory (PFT) may help unify competing theoretical perspectives of emotion. Specifically, we propose that PFT and the IR framework offer a point of origin for emotional experience.

The target article's emphasis on olfaction is a welcome reminder of the multimodal nature of conscious experience. Here, I explore the distinctive and even unique attributes of our sense of smell from the point of view of their bearing on and fit with a subcortical locus of sensory experience.

Morsella et al. put forward an interesting theory about the functions of consciousness. However, I argue that this theory is more about showing what is not the function of consciousness, and claiming that it does not integrate, than vice versa – as opposed to its proclaimed goal. In addition, the question of phenomenality and its relations with integration is still left open.

As mentioned in the target article by Morsella et al., the motor program's contents as a whole do not influence each other in the conscious field; however, research shows that some of their generated aspects could be sensitive to the context of the behavior. Such motivational “context-contamination” leads to voluntarily “turn off” of negative states. Taking place out of the conscious field, these adjustments would have critical influence on behavior, such as aggression.

Have Morsella et al. examined the fundamentals of consciousness? An experiment by Bar et al. (2006) has demonstrated the fundamental aspects of conscious and unconscious mechanisms of perception. The mental representations are not crisp and conscious like the perceived objects are, but vague and unconscious. This experiment points to the fundamental function of the neural mechanisms of consciousness in perception. Consciousness is also fundamental for the highest emotions.

Morsella et al. argue convincingly that consciousness is for adaptive voluntary action. What, then, is consciousness in a dream for? Two prior questions present themselves. In a dream, how do contents get into the conscious field? What are the properties of consciousness in a dream?

What does it take to explain the roles of consciousness for action and action for consciousness? This commentary claims that efficient functional explanations must meet two epistemological requirements: independent description of explanandum and explanans, and foundational explanation of their mutual relationship. It is argued that Morsella et al.'s target articledoes not fully meet these requirements.

Four questions are raised about the passive frame theory of Morsella et al.: (1) What is the relation of the theory to the response-selection-bottleneck view of attention? (2) Does the theory accommodate the contents of consciousness? (3) What about animals without skeletal muscles? (4) How do the contents of consciousness change with the development of automaticity?

Morsella et al. focus on the conscious nature of sensation. However, also critical to an understanding of consciousness is the role of internally generated experience, such as the content of autobiographical memory or metacognitive experiences. For example, tip-of-the-tongue states are conscious feelings that arise when recall fails. Internally driven experiences drive us to action and therefore are consistent with the current approach.

Can consciousness be understood through an association with voluntary skeletomotor action selection? Although flexible and integrated action selection is a plausible function for consciousness, a narrow focus on skeletomotor control neglects the contributions to conscious selfhood and subjectivity that rest on interoception and autonomic regulation (internal “action”). I consider these issues from the perspective of predictive processing.

Parenting consciousness, in line with passive frame theory, may be considered inseparable from action. With combined brain-imaging and cognitive-behavioral analyses, we are in the early phases of understanding how parental brain circuits regulate parental thoughts and behavior. Furthermore, work on parental consciousness confirms the importance of motor outputs and outlines related circuits that inform consciousness across generations.

Morsella et al. argue that science should not focus on high forms of consciousness. We disagree. An understanding of high forms of consciousness is invaluable to the scientific study of consciousness. Moreover, it poses challenges to the passive frame theory. Specifically, it challenges the notions that conscious thoughts are not connected and that consciousness serves skeletomotor conflict only.

Passive frame theory attempts to illuminate what consciousness is, in mechanistic and functional terms; it does not address the “implementation” level of analysis (how neurons instantiate conscious states), an enigma for various disciplines. However, in response to the commentaries, we discuss how our framework provides clues regarding this enigma. In the framework, consciousness is passive albeit essential. Without consciousness, there would not be adaptive skeletomotor action.

Emotional arousal enhances perception and memory of high-priority information but impairs processing of other information. Here, we propose that, under arousal, local glutamate levels signal the current strength of a representation and interact with norepinephrine (NE) to enhance high priority representations and out-compete or suppress lower priority representations. In our "glutamate amplifies noradrenergic effects" (GANE) model, high glutamate at the site of prioritized representations increases local NE release from the locus coeruleus (LC) to generate “NE hotspots.” At these NE hotspots, local glutamate and NE release are mutually enhancing and amplify activation of prioritized representations. In contrast, arousal-induced LC activity inhibits less active representations via two mechanisms: 1) Where there are hotspots, lateral inhibition is amplified; 2) Where no hotspots emerge, NE levels are only high enough to activate low-threshold inhibitory adrenoreceptors. Thus, LC activation promotes a few hotspots of excitation in the context of widespread suppression, enhancing high priority representations while suppressing the rest. Hotspots also help synchronize oscillations across neural ensembles transmitting high-priority information. Furthermore, brain structures that detect stimulus priority interact with phasic NE release to preferentially route such information through large-scale functional brain networks. A surge of NE before, during, or after encoding enhances synaptic plasticity at NE hotspots, triggering local protein synthesis processes that enhance selective memory consolidation. Together, these noradrenergic mechanisms promote selective attention and memory under arousal. GANE not only reconciles apparently contradictory findings in the emotion-cognition literature but also extends previous influential theories of LC neuromodulation by proposing specific mechanisms for how LC-NE activity increases neural gain.

Mather and colleagues present an impressive interdisciplinary model of arousal-induced norepinephrine release and its role in selectively enhancing/inhibiting perception, attention, and memory consolidation. This model will require empirical investigation to test its validity and generalizability beyond classic norepinephrine circuits because it simplifies extremely complex and heterogeneous actions including norepinephrine mechanisms related to higher cognitive circuits and psychopathology.

The ascending fibers releasing norepinephrine and acetylcholine are highly active during wakefulness. In contrast, during rapid-eye-movement sleep, the neocortical tone is sustained mainly by acetylcholine. By comparing the different physiological features of the norepinephrine and acetylcholine systems in the light of the GANE (glutamate amplifies noradrenergic effects) model, we suggest how to interpret some functional differences between waking and rapid-eye-movement sleep.