Development of a cognitive enhancer based on preclinical findings has translational potential (Stepan et al., in 30 April 2024 issue).
The Journal of Consciousness Studies has an issue out on the meta-problem of consciousness. (Unfortunately, it’s paywalled, so you’ll need a subscription, or access to a school network that has one.)
As a reminder, there’s the hard problem of consciousness, coined by David Chalmers in 1995, which is the question of why or how we have conscious experience, or as described by others, how conscious experience “arises” from physical systems.
Then there’s the meta-problem, also more recently coined by Chalmers, on why we think there is a hard problem. The meta-problem is an issue long identified by people in the illusionist camp, those who see phenomenal consciousness as an illusion, a mistaken concept.
Michael Shermer has an article up at Scientific American asking if science will ever understand consciousness, free will, or God.
I contend that not only consciousness but also free will and God are mysterian problems—not because we are not yet smart enough to solve them but because they can never be solved, not even in principle, relating to how the concepts are conceived in language.
On consciousness in particular, I did a post a few years ago which, on the face of it, seems to take the opposite position. However, in that post, I made clear that I wasn’t talking about the hard problem of consciousness, which is what Shermer addresses in his article. Just to recap, the “hard problem of consciousness” was a phrase originally coined by philosopher David Chalmers, although it expressed a sentiment that has troubled philosophers for centuries.
This essay addresses Cartesian duality and how its implicit dialectic might be repaired using physics and information theory. Our agenda is to describe a key distinction in the physical sciences that may provide a foundation for the distinction between mind and matter, and between sentient and intentional systems. From this perspective, it becomes tenable to talk about the physics of sentience and ‘forces’ that underwrite our beliefs (in the sense of probability distributions represented by our internal states), which may ground our mental states and consciousness. We will refer to this view as Markovian monism, which entails two claims: fundamentally, there is only one type of thing and only one type of irreducible property (hence monism). All systems possessing a Markov blanket have properties that are relevant for understanding the mind and consciousness: if such systems have mental properties, then they have them partly by virtue of possessing a Markov blanket (hence Markovian). Markovian monism rests upon the information geometry of random dynamic systems. In brief, the information geometry induced in any system—whose internal states can be distinguished from external states—must acquire a dual aspect. This dual aspect concerns the (intrinsic) information geometry of the probabilistic evolution of internal states and a separate (extrinsic) information geometry of probabilistic beliefs about external states that are parameterised by internal states. We call these intrinsic (i.e., mechanical, or state-based) and extrinsic (i.e., Markovian, or belief-based) information geometries, respectively. Although these mathematical notions may sound complicated, they are fairly straightforward to handle, and may offer a means through which to frame the origins of consciousness.
Keywords: consciousness, information geometry, Markovian monism.
This paper investigates the compatibility between the theoretical framework of the global neuronal workspace theory (GNWT) of conscious processing and the perturbational complexity index (PCI). Even if it has been introduced within the framework of a concurrent theory (i.e. Integrated Information Theory), PCI appears, in principle, compatible with the main tenet of GNWT, which is a conscious process that depends on a long-range connection between different cortical regions, more specifically on the amplification, global propagation, and integration of brain signals. Notwithstanding this basic compatibility, a number of limited compatibilities and apparent differences emerge. This paper starts from the description of brain complexity, a notion that is crucial for PCI, to then summary of the main features of PCI and the main tenets of GNWT. Against this background, the text explores the compatibility between PCI and GNWT. It concludes that GNWT and PCI are fundamentally compatible, even though there are some partial disagreements and some points to further examine.
Keywords: brain complexity; global neuronal worskpace theory; measurement of consciousness; perturbational complexity index; theory of consciousness.
© The Author(s) 2023. Published by Oxford University Press.
This study introduces a novel methodology for consciousness science. Consciousness as we understand it pretheoretically is inherently subjective, yet the data available to science are irreducibly intersubjective. This poses a unique challenge for attempts to investigate consciousness empirically. We meet this challenge by combining two insights. First, we emphasize the role that computational models play in integrating results relevant to consciousness from across the cognitive sciences. This move echoes Alan Newell’s call that the language and concepts of computer science serve as a lingua franca for integrative cognitive science. Second, our central contribution is a new method for validating computational models that treats them as providing negative data on consciousness: data about what consciousness is not. This method is designed to support a quantitative science of consciousness while avoiding metaphysical commitments. We discuss how this methodology applies to current and future research and address questions that others have raised.
Keywords: computationalism; consciousness; evidence; functionalism; methodology; modeling.
© The Author(s) 2021. Published by Oxford University Press.
Although the hippocampus is generally considered a cognitive center for spatial representation, learning, and memory, increasing evidence supports its roles in regulating locomotion. However, the neuronal mechanisms of the hippocampal regulation of locomotion and exploratory behavior remain unclear. In this study, we found that the inhibitory hippocampal synaptic projection to the medial septum (MS) bi-directionally controls the locomotor speed of mice. The activation of the MS-projecting interneurons in the hippocampus or the activation of the hippocampus-originated inhibitory synaptic terminals in the MS decreased locomotion and exploratory behavior. On the other hand, the inhibition of the hippocampus-originated inhibitory synaptic terminals in the MS increased locomotion. Unlike the septal projecting interneurons, the activation of the hippocampal interneurons projecting to the retrosplenial cortex did not change animal locomotion. Therefore, this study reveals a specific long-range inhibitory synaptic output from the hippocampus to the medial septum in the regulation of animal locomotion.
Keywords: GABAergic interneuron; exploratory behavior; hippocampus; inhibitory synapse; locomotion; septum.
Copyright © 2023 Chen, Arano, Guo, Saleem, Li and Xu.
Can one have a phenomenal experience to which one does not have access? That is, can you experience something without knowing? The dissociation between phenomenal ℗ and access (A) consciousness is widely debated. A major challenge to the supporters of this dissociation is the apparent inability to experimentally demonstrate that P-without-A consciousness exists; once participants report having a P-experience, they already have access to it. Thus, all previous empirical support for this dissociation is indirect. Here, using a novel paradigm, we create a situation where participants (Experiment 1, N = 40) lack online access to the stimulus yet are nevertheless able to retrospectively form judgements on its phenomenal, qualitative aspects. We further show that their performance cannot be fully explained by unconscious processing or by a response to stimulus offset (Experiment 2, N = 40). This suggests that P and A consciousness are not only conceptually distinct, but might also be teased apart empirically. STATEMENT OF RELEVANCE: A critical question in the scientific quest towards solving the problem of consciousness focuses on the ability to isolate conscious experiences at their purity, without any accompanying cognitive processes. This challenge has been augmented by a highly influential — yet controversial — dissociation suggested by the philosopher Ned Block between Phenomenal consciousness, or the “what it is like” to have an experience, and Access consciousness, indexing the ability to report that one has that experience. Critically, these two types of consciousness most typically go together, making it highly difficult — if not impossible — to isolate Phenomenal consciousness. Our work shows that the dissociation between phenomenal and access consciousness is not merely conceptual, but can also be empirically demonstrated. It further opens the gate to future studies pinpointing the neural correlates of the two types of consciousness.
Keywords: Access consciousness; Cognition; Consciousness; Phenomenal consciousness; Qualia; Unconscious processing.
Copyright © 2023 The Authors. Published by Elsevier B.V. All rights reserved.
In pre-clinical trials, a small molecule effectively regrew neurons, reduced inflammation, and improved memory, speed, coordination, grip strength, and more. The finding could have a profound impact on aging and the diseases that accompany it.
In conducting the research, scientists at the University of Texas MD Anderson Cancer Center, turned their focus to telomerase reverse transcriptase (TERT), an enzyme that is known to help synthesize and extend telomeres, the protective caps at the ends of chromosomes that help cells divide. TERT levels are reduced as we age.
Without sufficient levels of TERT, when our telomeres shrink or get seriously modified, they can lead to a process that continually damages our DNA, which causes cells to release inflammatory compounds that can in turn lead to aging, tissue damage, and cancer.
A new technique combining magnetic resonance imaging and x-ray fluorescence can characterize, with single-neuron resolution, the presence of toxic forms of iron that might be associated with neurodegenerative diseases.
Iron plays a major role in life. Most obviously, it keeps us alive, helping to ferry oxygen around our bloodstreams. It is also essential in cellular energy production, in the immune-system response, and in brain function—where it helps catalyze the synthesis of dopamine and other neurotransmitters. Iron can, however, be a double-edged sword. An iron excess has been implicated in many ailments, including neurodegenerative conditions such as Alzheimer’s, multiple sclerosis, and Parkinson’s disease—where dopaminergic neurons (neurons that use iron to synthesize dopamine) degenerate. It is thought that the toxicity of iron depends on how it is stored: iron firmly bound within proteins such as ferritin may be less toxic than iron more loosely bound to low-affinity sites, where it is more able to participate in reactions that generate cell-damaging hydroxyl radicals [1].
