DrmDoc

Although not today, I recently learned a very surprising bit of trivia...human are the only animals that have that protruding bit of bone and flesh we call a chin--and there's no agreement in science on why that is. Furtherstill, niether our primates cousins nor our hominds ancestors have or have had chins.

Please pardon this delayed response to your inquiry. Other than instinctive responses, which are primarily unconscious responses, some unconscious responses are a result of experience. From my perspective, our behavioral responses to stimuli issue from the thalamus in response the neural feedback (efference) the thalamus receives from surrounding cortical and subcortical structures in response to the stimuli (afference) the thalamus experiences. There are no cortical or subcortical efferent neural pathways that bypass the thalamus to our musculature; therefore, directives from our brain's neural hierarchy must pass through the thalamus to manifest as behavioral responses. In my opinion, conscious awareness generally occurs in the instance the thalamus receives neural feedback from the function of surrounding brain structures in response to the stimuli the thalamus receives from its sensory array. Learned responses isn't as much about focus as it is about continual stimulation of the afferent and efferent neural pathways associated with our behaviors. Learning is memory and memory, in my view, isn't the neural accumulation and storing of information, memory is the neural pathways that remain continuously stimulated by our experiences.

I believe you're asking about the nature of unconscious behaviors, which are the behaviors or reactions we appear to engage seemingly without conscious awareness. All behaviors we engage--including those defensive behaviors and reactions we engage without apparent conscious direction--are outputs of brain function. Our senses merely deliver information about ourselves and environment into brain function and it's that function that formulates and produces our responses. To some extent, all behaviors are learned, which for me infers that the neural pathways for our responses must be built and maintain by continual experience. Your continual experiences may have involved notable measures of threats where assessing and responding to potential physical harm have become second nature--it's akin to learning how to unconsciously maintain one's balance while riding a bike. For you, it's unconsciously maintaining your physical safety amid relaxed social settings.

Agreed and this isn't the forum for that discussion.

I agree and I now believe that perspective was @TheVat intent in adding that link to this discussion. The article does indeed explore a perspective on the incredible nauture of brain plasticity, but for me it further emphasizes my perspective on the subordinate nature of cortical structure relative to thalamic function..

The ideas expressed here were not clear from your previous comments regarding your link to Mr. Gazzaniga's article, but I would suspect moderators would not want us to digress in to speculations about other neural systems beyond the focus of this thread's discussion, which is the thalamus. There is, however, substantial research regarding the reticular activating system's contribution to conscious brain function by none regards that system the way they do thalamic function in the collection and relaying of the sensory information that our cognitive sense and expression of self--relative to our sensory environment--relies on. Forgive my misquote; however, in the opening paragraph to Mr. Gazzaniga's article he mentioned the case of a "white-collar worker" with a link to "without a brain". Mr. Gazzaniga goes on to discribe the worker as a "normal 44-year-old" with an "acceptable IQ" and a "gaping fluid-filled cavity where a brain would normally be." Selecting Mr. Gazzaniga's "without a brain" link led me to a Lancet article discussing the case of a man who suffered from postnatal hydrocephalus--and this was not the only reference to hydrocephalus cases in the focus of Mr. Gazzaniga's article. In fact, Mr. Gazzaniga also referenced the case of a 60 year-old male with a "head full of fluid and only a thin sheet of cortex" and the case of a 72 year-old living "largely without what we might recognize as 'a brain.'" The links to both these cases reference individuals with various types of hydrocephalus. I have to wonder if you read any of this article as Mr. Gazzaniga most certainly do reference cases arising from hydrocephalus. My apologies if my comments inferrred this as your first, but I share a similar sentiment when it comes to the depiction of hydrocephalus conditions as being "without a brain".

I believe your article references a condition known as hydrocephalus; wherein, cerebrospinal fluid fills the ventricles of the brain and compresses brain tissue into thin layers. It's disengenuous for the article's author to describe such individuals as having "no brain" because, in fact, these individuals do possess brain structures and tissue that can function as well as a normal brain when adapted sufficiently early in gestation or infancy. Therefore, cortical tissue is indeed required in these case and those of individuals with this condition who appear to lead normal, well adapted lives. For a clearer perspective of how behavior is affected by the absence or destruction of brain structure, you may want to look into decorticate and decerebrate brain studies involving both humans and animals.The effects of decortication and decerebration can be profound but survivable depending on whether there is brainstem damage and the stage of brain development when decortication/decerebration occurs. However, neither decortication, decerebration, nor hydrocephalus deminishes what this discussion thred topic suggests about what the thalamus does for brain function. From our sensory array, to our thalamus and cortex, there is indeed a holistic nature to what our central nervous system does to produce human conscousness but that doesn't render consciousness as a unique quality or exclusive to humans--which is what science rather than philosophy most clearly evinces, IMO.

Apologies, but I have very little interest in philosophy. However, if my philosophical baggage is weighted by methodologies that objectively and consistently provide and support evidence that either proves or disproves a hypothesis, then indeed I lean quite heavily on and will, unfortunately, continue to do so.

I agree; philosophy is philosophy and science is science.

https://www.msn.com/en-us/health/other/more-than-a-simple-relay-station-thalamus-may-guide-timing-of-brain-development-and-plasticity/ar-AA1KfkSf?ocid=msedgdhp&pc=HCTS&cvid=9c3891007f444aea94c6a49cfb2b23b0&ei=11 Yet more support for the central role of the thalamus in cognitive outcomes. From the article: "Our data indicate that the thalamus likely plays a more active role in determining when cortical regions are plastic, and therefore when they exhibit both adaptability and vulnerability to our environments." Interestingly, Sydnor and her colleagues observed that the maturation of structural connections between the human thalamus and cortex followed a sensorimotor-to-association sequence. This suggests that the development of cortical regions in children and adolescents is aligned with changes in the strength of connections with the thalamus. Thus, the thalamus might serve as a "timekeeper" of cortical maturation. "This is important given that the pace of cortical maturation is linked to cognitive and psychological outcomes," The article suggests that the thalamus is indeed "more than a simple relay station." Again, more evidence that cortical development, thereby, cortical function is secondary to thalamic connections and function.

I disagree; homeostasis explains everything about emergences of brain function--it's the engine propelling that function.

The idea that an organism must demonstrate "mental capabilities" or form some mental construct such as a "cognitive map" to be possessing of consciousness is a human standard. It's flawed because it infers no distinction between attributes of mind and consciousness--it's the idea that one attribute cannot exist without the other. Consciousness can certainly exist without the sophistication of a mind because consciousnes, at its most basic and primal level, is merely awareness. The sophistication of having a mind suggest a level of consciousness based wholely on a human standard, which is the only standard by which we can assess that quality in other organisms. In previous comments I said that "consciousness is relative" but, in my view, mind is not. Mind, from my perspective, is shown by non-instinctive behaviours--behaviours that suggest a thought process, which are behaviours we can readily determine based on our standards for that process.

You appear to be assessing consciousness solely by a human standard. You appear to be saying here that if an organism doesn't behave the way we do, that organism doesn't possess consciousness. If true, all you're suggesting is that plants, bacteria, and jellyfish doesn't possess human consciousness. In fact, these organisms may possess plants, bacteria, and jellyfish consciousness. When we remove classification bias from our perspective, we should find that consciousness is relative.

Yes! Most assuredly so--IMO Is a thermostat an organism? If you will, consider the wording in my comments, you may find my meaning a bit more nuanced than your perception here.

Any organism, if I may follow up a bit further here, that demostratively responds to stimili possesses, by my definition of the term, consciousness. Whether that organism's measure of consciousness rises to the level of human consciousness is dependent on whether their consciousness measure enables behaviours we perceive as thought driven--essentially behaviours suggestive of intelligent awareness by human standards.

There's quite a bit here that's clearly desevering of a focused response, but it's clear that my perspective requires some clarification centered around my meaning of emergence and sense of self. Correct me if I'm mistaken, but I believe we all agree that our sense of self--our sense of whom and what we are relative to our mental, social, and physical environment--is solely dependent on the the information our brain receives and experiences. If true, that empirically renders our sense of self as secondary to that information, which means our sense of self--relative to brain function--is a response to information about self and that response cannot emerge within or through brain function without that information. For those of us who are fimiliar with the anatomy of our central nervous system (CNS), we know that information about ourselves and our environment is channelled as sensory afference into the hierarchy of our CNS through that heirarchy's afferent neural connections to our body's sensory array. Given this perspective, one might say that it's our sensory array that gives rise to our sense of self, but that wouldn't be, IMO, precisely true. Our sensory array merely provides our brain with information about the separate and diverse affects of life experience, but where those affects initially converge and combine in the brain as an all encompassing sensory perception of self and our environment is indeed the thalamus. Although the corpus callosum serves a critical function as @TheVat noted, that function merely combines the processing power of the two hemispheres after they have received data from the thalamus and its relays through other subcortical structures. Unlike the bombing of all roads to the midwest through Chicago in @TheVat analogy, destruction of the thalamus is fatal to brain function but not the other way around. Abraham Lincoln who, for example, sustain no thalamic damage but did sustain critical damage to his cortex, would have survived his assailant's attack if physicians were as knowledgeable then about brain swelling and wound treatment as they are now. There's a reason why the thalamus is shielded by cortical structure and why the cortex mirrors the thalamus' hemispheric configuration--but that's a discussion for another time. Consciousness, by my definition, is merely that measure of awareness suggested by an organism's responses to stimuli. Relative to brain function, consciousness is an efferent product of brain function that does not occur or emerge without the brain's afferent neural connections to the thalamus, which is what I believe the article findings clearly suggest. Relative to emergence, in my view, consciousness and our sense of self are merely the lights (efference) switched on in brain function by thalamic function (afference).

It would likely have operated the same as it does now in a land based environments. Olfaction essentially involves the detection of scent molecules that can carry well through both water and air environments. If we're settled on "emerging", isn't it reasonable to conclude that our sense of self emerges through our experiences and it we're discussing where detection of those experiences initially converge in the brain before manifesting as consciousness, then the thalamus is likely that solitary brain structure from which our sense of self emerges.

Although gustatory and olfaction operate to provide the brain with an encompassing sense of flavor, from my understanding of brain evolution, they are routed differently because taste perception had the most immediate impact on ancestral species' survival, which required immediate survival responses. Those immediate responses initiate through the thalamus. Olfaction was useful to ancestral species for the immediate but indirect detection or predation of food sources, while gustatory or taste required species to have direct and perilous physical contact with those food sources. Smell made ancestral animals aware of potential food sources without physical risk and taste was likely adapted as these animals learned to mediate what smelled good by what was safe to consume.

Much like my opinion on political polls, I agree that small samplings are not always representative of larger groups. I believe we can both agree that flaws can be found in most if not all studies. However, as you may have preceived through our previous discussions, my thoughts about the thalamus doesn't hinge on single studies but rather the cumulative empirical evidences these studies appear to provide overall. As the author of this article assesses, these Beijing's findings offers support for the role of the thalamus--much like a single vote casted in some grand election. I agree and neither have I in my comments here. If you'll recall my initial comments, I said I beiieve the findings this article reveals support my thoughts on the "central role of the thalamus in the emergence of our sense of self." The article provides support for other research that details the dependence of cortical function on thalamic function. That research empirically details the neural path all sensory afference must traverse to reach our cerebrum. Every sensory neural pathway--other than olfactory--that fills our brain with data about our environment and self, converge at the thalamus first and it is the thalamus that relays or disseminates that data to the cerebrum. We derive our sense of self from the data our brain receives about our environment and self--and if it's the thalamus that disseminates that data, then why is it so difficult to believe that our sense of self emerges from or through the thalamus?

Although I believe your perspective has merit, I think the article speaks for itself by "offering new empirical support for theories that assign a central role to thalamic structures rather than cortical areas alone." I think that's a great question and, as I now consider, all organisms along the evolutionary chain were likely biologically driven by variance of homeostasis and any that acquired a response system sufficient to maintain homeostasis--neural or otherwise--may have been capable of evolving behaviors suggestive of intelligent awareness--awareness that distinguishes thoughtful behaviors from those we may perceive as instinctive.

https://www.msn.com/en-us/health/other/thalamic-nuclei-observed-driving-conscious-perception/ar-AA1Cx8yH?ocid=socialshare From the article: "Beijing Normal University-led researchers have identified specific high-order thalamic nuclei that drive human conscious perception by activating the prefrontal cortex. Their findings enhance understanding of how the brain forms conscious experience, offering new empirical support for theories that assign a central role to thalamic structures rather than cortical areas alone." This finding appears to abut nicely to my thoughts on the central role of the thalamus in the emergence of our sense of self.

Oh, I see. That article was just click bait for science readers. Thanks to you both, Swansont and Sohan!

I understood dark matter to be that undetectible matter whose gravitational effects are not explained by visible matter. If I now understand correctly, baryons are not that invisible matter? Just missing protons? Forgive my ignorance but aren't protons matter?

Greetings Astronomers, This may be an old subject but could you help me understand. Does this article suggests that dark matter is no longer dark? This article suggests that the baryonic gas found among the intergalactic medium--the space between galaxies--comprises 79% of our universe's missing matter. Am I reading that article correctly?

Hello All, I began this latest round of discussions declaring the thalamus as the likely brain structure from which our sense of self arises. If it wasn't clear from my previous comments, my reasoning behind this is the well established, empirical truth that all sensory roads to the upper regions of our central nervous system (CNS) lead initially to the thalamus. From the moment in vitro, when our CNS developes the capacity to receive sensory data, it is the thalamus that receives the initial impact of that data and distributes that sensory information to all regions of brain structure. Think about it for moment, everything that has a physical/materail impact on our sensory system is initially and primarily detected by the thalamus and what impacts us physically/materially is how we derive our physical/material sense of self. How we physically determine what we are and who are is dependent on our physical sensory and that sensory doesn't reach any region of the cerebrum without first impacting the thalamus; therefore, it is our thalamus that relays in total what impacts our physical sense of self and the thalamus that, uncontrovertibally and at a minimum, give rise to our physical sense of who and what we are. It's simple algebra--if a=b, and b=c, then a=c!