I have like 0 experience or knowledge about brain signals and all that stuff but I'm curious about how much we know about the brain in terms of like tricking your brain that with simulation of pain. The reason why i got curious is because I love video games and I just started imagining like some sort of real life game or even just using virtual reality where if you were to get hurt in the game in some spot you would feel pain in real life. I'm not sure if there's some sort of article or like something online where it explains this sort of stuff that I'm talking about.
It appears that stimulation of the thalamus would invoke feeling of pain:
Direct deep brain stimulation (DBS) in the VP thalamus from patients without pain typically evoked nonpainful, paraesthetic sensation. DBS at the core and posterior inferior region of the VP thalamus can evoke pain sensation without specific topographic distribution. However, warm sensation was more frequently evoked in the posterior than in the core region. Intensity of sensation was dependent on current and frequency of microstimulation. (Yen and Lu, 2013)
The trouble is that deep brain stimulation (DBS) is a surgical procedure, so it would not be viable for any sort of virtual reality gaming, however it seems that Trans-cranial Magnetic Stimulation (TMS) could possibly be used if it could be developed and proven to be safe enough for this purpose.
It would have to be proven to target the specific parts of the brain required. It would have to be proved not to be stimulating other areas that could cause unwanted and possibly dangerous consequences.
As I have very small amounts of knowledge on what happens in the brain neurologically compared to some people here, I have had to do a lot of reading to start with and I believe I have a basic idea of how this possibly could be done.
First of all we need to look at how pain is registered in the brain.
Nerves as pain sensors
A nociceptor is a type of sensory receptor at the end of a sensory neuron's axon that responds to damaging or potentially damaging stimuli by sending signals of pain to the spinal cord and brain. This process is called nociception.
The peripheral terminal of the mature nociceptor is where the noxious stimuli are detected and transduced into electrical energy. (Fein, 2012) When the electrical energy reaches a threshold value, an action potential is induced and driven towards the central nervous system (CNS). This leads to the train of events that allows for the conscious awareness of pain.
Message transfer to the brain
Afferent nociceptive fibers (those that send information to, rather than from the brain) travel back to the spinal cord where they form synapses in its dorsal horn — the posterior grey column of the spinal cord.
After reaching the specific lamina within the spinal cord, the first order nociceptive project to second order neurons. The second order neurons then send their information via two pathways to the thalamus at the centre of the brain: the dorsal column medial-lemniscal system and the spinothalamic tract (or otherwise known as the anterolateral system). The first is reserved more for regular non-painful sensation, while the lateral is reserved for pain sensation.
Reaction from the thalamus
Initially, Brodmann areas (BA) 1, 2 and 3a and 3b (Brodmann, 1909/1994; Vogt, 1919; Kaas, et al., 1979) of the Cerebral Cortex were considered to make up the primary somatosensory cortex of the human brain, however, BA 3b is now conceived as the primary somatosensory cortex because:
- it receives dense inputs from the NP nucleus of the thalamus;
- its neurons are highly responsive to somatosensory stimuli, but not other stimuli;
- lesions here impair somatic sensation; and
- electrical stimulation evokes somatic sensory experience. BA 3a also receives dense input from the thalamus; however, this area is concerned with proprioception.
Reaction from other parts of the brain
The primary somatosensory cortex contains cells that project to the secondary somatosensory cortex (S2). This is divided into several "areas". An area at the entrance to the lateral sulcus, adjoining the primary somatosensory cortex (S1), is called the parietal ventral (PV) area.
Area S2 is interconnected with BA 1 and densely so with BA 3b, and projects to BA 7b, insular cortex, amygdala and hippocampus.
The insular cortex, which is in both hemesperes of the brain, are believed to be involved in consciousness and play a role in diverse functions usually linked to emotion or the regulation of the body's homeostasis. These functions include perception, motor control, self-awareness, cognitive functioning, and interpersonal experience.
One thing I knew before the research is that it is the amygdala and hyppocampus which initiates the 5F response (fright/flight/fight/freeze/fawn response) to threats.
Brodmann, K. (1909/1994). Localisation in the Cerebral Cortex, Translated by Laurence J. Garey (New York, NY:Springer Science): pp 106—110 ISBN-13: 978-0387269177
Free PDF available from http://www.appliedneuroscience.com/Brodmann.pdf
Fein, A. (2012). Nociceptors and the perception of pain (Farmington, CT:University of Connecticut Health Center)
Free PDF available from http://cell.uchc.edu/pdf/fein/nociceptors_fein_2012.pdf
Kaas, J. H., Nelson, R. J., Sur, M., Lin, C. S., and Merzenich, M. M. (1979). Multiple representations of the body within the primary somatosensory cortex of primates, In: Science 204(4392): pp 521—523 DOI: 10.1126/science.107591 PMID: 107591
Yen, C., and Lu, P. (2013). Thalamus and pain, In: Acta Anaesthesiologica Taiwanica 51(2): pp 73—80. DOI: 10.1016/j.aat.2013.06.011
Free PDF on Creative Commons Attribution – NonCommercial – NoDerivs (CC BY-NC-ND 4.0) at http://www.e-aat.com/article/S1875-4597(13)00066-0/pdf