In this commentary we discuss the possibility of subcortical consciousness and its implications for fetal anesthesia and analgesia. We review the neural development of structural and functional elements that may participate in conscious representation, with a particular focus on the experience of pain.

Every time we look around we can see a rich and detailed world surrounding us. Nevertheless, the majority of visual information seems to slip out of our thoughts instantly. Can we still say that this fleeting percept of the entire world was a conscious percept in the first place, as Block proposes?

Mental time travel and theory of mind develop, both phylo- and ontogenetically, at the same stage. We argue that this synchrony is due to the emergence of a shared competence, namely, the ability to become aware of frames of reference.

A species like ours, whose life critically depends on the ability to foresee, plan, and shape future events, is vulnerable to dysfunction if any one facet contributing to what Suddendorf & Corballis (S&C) call “mental time travel” (MTT) is affected by disease. Although the authors mention brain pathology as a potential cause of disturbed MTT, they fail to explore psychopathological syndromes as a source to better understand the significance of MTT for normal functioning and adaptive behaviour.

Dijkerman & de Haan (D&dH) propose a somatosensory perceptual pathway that informs a consciously accessible body image, and an action pathway that provides information to a body schema, which is not consciously accessible. We argue that the body schema may become accessible to consciousness in some circumstances, possibly resulting from cross talk, but that this may be detrimental to skilled movement production.

Merker suggests that the thalamocortical system is not an essential system for consciousness, but, instead, that the midbrain reticular system is responsible for consciousness. Indeed, the latter is a crucial system for consciousness, when consciousness is regarded as the waking state. However, when consciousness is regarded as phenomenal consciousness, for which experience and perception are essential elements, the thalamocortical system seems to be indispensable.

The fact that early visual processing has a larger capacity than later visual processing can be explained without positing distinct systems for phenomenology and cognitive accessibility. While phenomenology may overflow forced-choice reports, the later can also overestimate the former, as in the case of blindsight. Metacognitive measures of awareness offer a way to address the “methodological puzzle” of consciousness research.

Merker's core idea, that the experience of being conscious reflects the interactions of actions, targets, and motivations in the upper brainstem, with cortex providing the content of the conscious experience, merits serious consideration. However, we have two areas of concern: first, that his definition of consciousness is so broad that it is difficult to find any organisms with a brain that could be non-conscious; second, that the focus on one cortical–subcortical system neglects other systems (e.g., basal forebrain and brainstem cholinergic systems and their cortical and thalamic target areas) which may be of at least equal significance.

Research on the neural correlates of sexual arousal is a growing field of research in affective neuroscience. A new approach studying the correlation between the hemodynamic cerebral response and autonomic genital response has enabled distinct brain areas to be identified according to their role in inducing penile erection, on the one hand, and in representing penile sensation, on the other.

I explore the implications of recognizing two forms of access that might be constitutively related to phenomenal consciousness. I argue, in support of Block, that we don't have good reason to think that the link to reporting mechanisms is the kind of access that distinguishes an experience from a mere state.

Suddendorf & Corballis (S&C) propose that the capacity to flexibly forsee the future was a critical step in human evolution and is accomplished by a set of component processes that can be likened to a theater production. Understanding the brain-bases of these functions may help to clarify the hypothesized component processes, inform us of how and when they are used adaptively, and also provide empirical ways of exploring to what degree these abilities exist and are implemented similarly (or differently) across species.

Painful stimuli evoke functional activations in the cortex, but electrical stimulation of these areas does not evoke pain sensation, nor does widespread epileptic discharge. Likewise, cortical lesions do not eliminate pain sensation. Although the cortex may contribute to pain modulation, the planning of escape responses, and learning, the network activity that constitutes the actual experience of pain probably occurs subcortically.

The parietal cortex is divided into two major functional regions: the anterior parietal cortex that includes primary somatosensory cortex, and the posterior parietal cortex (PPC) that includes the rest of the parietal lobe. The PPC contains multiple representations of space. In Dijkerman & de Haan's (D&dH's) model, higher spatial representations are separate from PPC functions. This model should be developed further so that the functions of the somatosensory system are integrated with specific functions within the PPC and higher spatial representations. Through this further specification of the model, one can make better predictions regarding functional interactions between somatosensory and visual systems.

Suddendorf & Corballis (S&C) argue that episodic memory is the most flexible and recently evolved memory system, and point to the reorganization of prefrontal cortex throughout human evolution as the neuroanatomical substrate. Their approach, however, fails to address the unique role that the hippocampus, a primitive brain region, plays in creating and recalling episodic memories, as well as future event construction.

Block holds that there can be “phenomenology,” “awareness,” and even awareness of the phenomenology, without cognitive access by the subject. The subject may have an experience and be aware of the experience, yet neither notice it nor attend to it. How that is possible is far from clear. I invite Block to explain this very fine distinction.

The centrencephalic theory of consciousness cannot yet account for some evidence from both brain damaged and normally functioning humans that strongly implicates thalamocortical activity as essential for consciousness. Moreover, the behavioral indexes used by Merker to implicate consciousness need more development, as, besides being somewhat vague, they lead to some apparent contradictions in the attribution of consciousness.

There is a task-specificity in the visual-tactile interaction for perception: The polymodal posterior parietal cortex is related to the comparison of the shapes coded by different sensory modalities, whereas the lateral occipital complex is the part of the network for multimodal shape identification. These interactions may be mediated by some latent pathways potentiated by sensory deprivation or learning.

We consider three possible reasons why humans might accord a privileged status to emotional information when mentally traveling backward or forward in time. First, mental simulation of emotional situations helps one to make adaptive decisions. Second, it can serve an emotion regulation function. Third, it helps people to construct and maintain a positive view of the self.

States of sensory absorption may offer a means to disentangle perception from report. Interestingly, such states lead to an antagonistic relationship between perceptual and cognitive-access networks, suggesting that perceptual awareness does not depend on a read-out by high order cognitive-access mechanisms. Rather, it may emerge internally, through a cooperative coding dynamics, whereby each neuron simultaneously represents and reads-out the perceptual awareness state.

Episodic memory is certainly a unique endowment, but its primary purpose is something other than to provide raw material for creative synthesis of future scenarios. Remembered episodes are exactly those that are worth telling. The function of episodic memory, in my view, is to accumulate stories that are relevant to recount in conversation.