Where in the brain do we sense our internal organs?

[icakeov]

Hello,
I know that the sensory cortex in the postcentral gyrus collects sensory information from different parts of the body, but in all the drawings and explanations, I see that it only gathers information from the surface of the body.

Which part of the brain gathers information from our organs and overall, internal parts of the body. I assume there are a lot of sensory, afferent nerves everywhere in the body. Is this a separate part of the brain that is in charge of these sensory inputs?

Also, I gather that although we do have the ability to sense the pain in our stomach after we've eaten something, we don't have a motor area set-up in the brain to control the stomach "behavior", in the way that the precentral and postcentral gyruses (gyri?) seem to relate directly to each other.

On that note, a side question: do these two gyruses actually relate directly between each other and in which way? It is one thing to have the ability to sense touching something with my right forefinger, but moving my forefinger is a separate process, but are these two neural processes right next to each other in the Cortical homunculus? (I hope I managed to express this one properly)

Any thoughts welcome.

 

[icakeov]

Or to put it another way, are there any sensory nerves in the body whose pathways do not end up in the sensory cortex?

I do see that the cortical homunculus has one section at the far edge that is called "intra-abdominal". I am assuming this would be the part of the brain that can sense signals from inside of the body.

 

[Laroxe]

Sensation is an interesting idea particularly when it comes to things like pain and while the sensory cortex is clearly involved, its not a mater of sensory nerves just terminating there, I don't think its that simple. It is in fact very difficult to make clear links between specific brain areas and particular processing tasks. Pain perception involves a number of processes in both the peripheral and central nervous system, it involves labelling a sensation, giving it a value, emotional responses etc. Many internal organs appear to have relatively few sensory nerves that are not directly involved with their function which can lead to the interesting symptom of referred pain. Because some sensory pathways share certain routes to the brain, the brain mistakenly senses the pain in one of the shared areas rather than the real source. Cardiac pain is often perceived going down the arm, liver pain and some ulcers, felt in the right shoulder. The best we can say is that sensory nerves will activate neural networks in the brain often involving a large number of areas.

 

[icakeov]

Great! Thanks Laroxe. I was recently watching Damasio's explanation of how humans feel emotions:

That was what got me thinking about this topic.
Do you have any comments on his approach to the process of us feeling of bodily emotions?

 

[Laroxe]

Hi, the video was interesting and had some good points but there were a few things that made me think. The first was how difficult it is to try and separate brain and body functions when in reality the brain is embodied they represent parts of a highly integrated and interactive system. he described a linear relationship over time, the brain senses a threat that leads to autonomic arousal etc. In fact its not quite that straightforward. We know that in general our thoughts feelings and behaviours tend to be internally consistent but really there is no first in line if we induce changes in our body that resemble the effects of anxiety, the person feels anxious, if we induce behaviours associated with certain emotions, these emotions are evoked. In this facial expressions seem particularly important.
He also seems to imply that we only engage with emotions at the point they become noticeable when in fact our emotions are always engaged, there are few things in our world that we do not evaluate, that is associate with particular value to ourselves, its difficult to see emotion as separate from cognition, they are intimately connected. Our evaluations guide the way we think about things, interpret actions and behave. he was right when he said we were constantly reacting to our environment. You can pick up a toy lie detector that measures galvanic skin responses (changes in resistance caused by sweating) its actually fascinating to see how quickly and powerfully our body responds to things, even simple words induce powerful physiological effects, part of which relates to hormone production and several hormones act directly as both neuromodulators and neurotransmitters. I suspect he's right in saying extreme emotions induce certain types of created experiences, but these do in fact reflect the underlying physiology, people become aware of their heart beat and have palpitations, but that's real and emotions have a powerful effect on gut movement. I think these everyday effects are rather different to the extreme states of fear etc that take over our functioning.

 

[Pythagorean]

Sensory cortex generally relates to senses humans experience. The sensors in other parts of the body don't necessarily bring detections to human attention. They just react to them. Like CO2 sensors up regulate breathing rhythm when it senses too much co2. No need for sensory cortex in that case.

 

[icakeov]

Thanks for all the feedback on this! I think he is on board with the fact that emotions run in the background all the time, I think he was referring specifically to when we become "aware" of our emotions, which was the example of the patient that didn't have that ability.

The main distinction that I've gotten out of that video is that emotions are in the motor domain, basically only come up as a behavior, whereas feelings are in the sensory domain, basically how we feel as a result of having emotions "behaviorally" (physical facial expressions, movements, chemical molecule releases).

That is why I started thinking that regular sensory organs give us the perception of the outside world, whereas the sensors that monitor the places where emotions are expressed, that would be the only way how we can "feel" about what's going on in our bodies.

Thus, I started wondering where are these sensory systems that "capture" emotions.

Thoughts?

 

[atyy]

Which part of the brain gathers information from our organs and overall, internal parts of the body. I assume there are a lot of sensory, afferent nerves everywhere in the body. Is this a separate part of the brain that is in charge of these sensory inputs?

https://en.wikipedia.org/wiki/Vagus_nerve

 

[icakeov]

Sweeet! Thanks @atyy !