A discussion I'm having with a colleague raised this question: if a nociceptive stimulus is applied, before the brain determines that it is important enough to be "pain" (the unpleasant sensory and emotional experience etc) can it be perceived?
For example, a person participating in body suspension where the body is suspended from large hooks will say the experience of having hooks inserted ks definitely painful. They later experience the suspension part as perhaps even euphoric. This I can understand in terms of appraisal, hormone release, social context etc
Then a person who gets a shark bite may say "I felt a dull thump at first, but it didn't hurt until I got back on land".
The question is: is the "dull thump" nociception, or is it activation of other receptors and pathways? It's not pain at the time, so what is it?
pain is a perception and one needs cortex to perceive pain; nociception is a sensation and requires sensory processing of nocive stimulation. One can have pain without nociception (generated by the brain) or nociception without pain: for example under influence of CNS-acting drugs or when spinal pathways to the brain are damaged one will not feel pain, but may still have spinal reflex.
I get the difference between having pain and not necessarily having any stimulus (it's an experience), but is it possible to experience something other than pain along with nociception is the question - I think it's a little different from the reflex which is movement...
Per definition nociception is "the neural process of encoding and processing noxious stimuli". In your shark example it is likely stress-induced analgesia plays a role. It has been shown that acute stress has an anti-nociceptive effect by activating descending inhibitory pain pathways (Butler and Finn, Stress-induced analgesia; 2009; Progress in Neurobiol; Lau and Vaughan, 2014; Descending modulation of pain: the GABA disinhibition hypothesis of analgesia; Current Opinionin Neurobiol). So your noxious stimulus is present, but the experienced pain might be numbed through this mechanism. On top of that nociceptive fibers can also be activated by innocuous mechanical, warm and cold stimuli. It might be that these sensation are also present when experiencing a painful stimulus, but my guess would be that the pain sensation has priority as nociception plays an important physiological role as warning system.
Hi Bronnie, I am thinking about two possibilities that may help you with finding the answer. one is Measurement of Nociceptive Flexion Relfex. another one could be Heart rate and blood pressure measurements. because of their tight link with autonomic system (sympathetic and parasympathetic). pain is related to autonomic system and Heart rate and BP also. there should be a link.
I would agree nociception is just activation of nociceptive fibers. What the nervous system does with that signal through the multiple points of modulation will ultimately determine the emergent experience output of the brain (i.e. pain, no pain or something else).
Hassan, I think the autonomic system response is modulated strongly by appraisal, so perhaps is less useful as a measure of nociception, although it can be related especially in the case of severe tissue damage.
Hubert I think that's what I was looking for - whether nociceptive fibres can be activated without exceeding the threshold for firing something that could be experienced as pain, eg pressure.
Kory I certainly agree with your statement - it was just that shark bite experience that's reported so often in the media (and literature), I wasn't certain whether this was a nociceptive response damped down by descending inhibitory mechanisms (and cortical modulation of attention and so on), or whether it was activation of some other set of receptors. So it probably is mechano receptors in the case of shark bite, with the "threat value" not represented in experience (or not produced as an output) because other goals are prioritised. Whew!
If I recall correctly, the other sensation you are looking for may be itch. Perhaps the recent article in Neuron by Braz et al (Transmitting Pain and Itch Messages: A Contemporary View of the Spinal Cord Circuits that Generate Gate Control) might be helpful.
Thanks for reminding me about that Wolf-Oliver Krohn. It's probably part of the phenomenon, as is the material Hubert shared. It helps me in my thinking anyway!
what is the difference between signal and information (and context)? Is it similar to the difference between nociception and pain? I think signals (nociception) can be processed in the brain to produce different phenomena (pain is the most predominant feature in humans and closely related in terms of time). On the other hand, there can be other channels to pain than nociception.
Pain patients can reveal to us their pain experience to which we agree with them upon, believe and share because it matches a representation of what pain should be like.
What I like about your question is that it makes me think outside the "medical box" of pain-nociception axes.
Since our body is a network, nocicpetion could be channelled everywhere and the pain phenomena it produces is made up of a multilevel pattern of changes.
This leads me to question my tool with which I "see" the changes which nociception triggers. We usually "see" pain and perhaps other phenomena are hidde nin a black spot.
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