# Thinking with organs/systems other than the brain

Neurohormones are produced in many different bodily systems other than the brain--skin, intestines, stomach, etc. Has there been any research suggesting whether or not some people might actually perform cognitive functions normally associated only with the brain (like processing sensory input to make complex decisions) with parts of their body other than their brain?

For example, crows have demonstrated they are capable of complex problem solving, even though they do not have a cerebral cortex. Scientists now believe crows use their telencephalon to perform complex reasoning tasks.

Thus, crows use a part of their physiology not previously associated with complex reasoning for complex reasoning.

So, to extend the idea even further, could humans also be using organs or systems to handle processes usually presumed to be handled only by the brain?

Since so many bodily systems produce neurohormones, they seem like likely possible candidates.

Has any research been done to test this proposition?

• Welcome to CogSci.SE! It's kind of hard to answer your question right now. Would you mind defining "think" in the most specific way that you can? Do you just mean information processing or something more involved than that? – Seanny123 Aug 7 '16 at 0:52
• Let me know if that helps – Thom Blair III Aug 7 '16 at 1:05
• That's perfect! – Seanny123 Aug 7 '16 at 2:11
• cerebral cortex is telencephalon, so it's not really surprising that birds use their homologue of our cortex for thinking. – honi Aug 8 '16 at 0:54
• I really think the answer to this depends on what you mean by "thinking" and "information processing". There are systems outside the brain which take an input and modify it in someway to produce an output (such as the neuroendocrine integration you mention). But things like reasoning require more sophisticated networks of cells which are only found in the brain. For a more general and fun definition of cognition you could see this paper about "cognition in plants"!: um.es/logica/paco_calvo/… – splint Aug 9 '16 at 8:07

To answer your question – no. It is the brain that ‘thinks’ and does complex cognitive reasoning. And actually, it depends what you mean by ‘thinking’. I have studied Neuroscience for a long time and there is no evidence to suggest that the type of complex reasoning you are talking about is performed by any organ other than the brain (in any animal).

It is true that other organs than the brain produce neurohormones, but it doesn’t mean these organs are the site of action of these neurohormones.

As for the specific parts of the brain involved – I don’t know – there is still a lot of research on this going on. The telencephalon is part of the brain, and includes both the cerebral cortex and sub-cortical regions. There is strong evidence to suggest the prefrontal cortex (cortex) and hippocampus (sub-cortical) are highly-involved in complex reasoning. And many other parts of the brain are also involved in conscious and unconscious cognitive processes.

Yes, we also have a brainstem, a spinal cord and an enteric nervous system, which perform complex neural computations – but they do not ‘think’ the way we commonly think about thinking. As for non-neural parts of an organism – there is no evidence that those ‘think’.

I hope this help. I'd be interested in what others have to say on this.

Regards

HM

BSc (Biomedical Sciences – Neuroscience) (UCL)

#

Here are some references that I studied from last year:

These University-level textbooks: --- "Anatomy and Physiology" by Tortora et al; --- "Neuroscience" by Purves et al; --- "Principles of Neural Science" by Kandel et al;

Also: The Making of Memory by Steven Rose; The Human Brain by Susan Greenfield;

From Neuron to Cognition via Computational Neuroscience .https://mitpress.mit.edu/neuron-cognition

Cerebral cortex – Scholarpedia article www.scholarpedia.org/article/Cerebral_cortex

An integrative theory of prefrontal cortex function, Miller & Cohen 2001, Annual review of neuroscience

The hippocampal system mediates logical reasoning about familiar spatial environments, Goel et al 2004 - Journal of Cognitive Neuroscience, MIT Press

Role of the hippocampus in imagination and future thinking Maguire & D Hassabis - 2011 - PNAS

Think Twice: How the Gut's "Second Brain" Influences Mood and Well ... www.scientificamerican.com/article/gut-second-brain/

As for evidence that anything else than networks of neurons can enable cognitive processes – eg. skin in your leg or bone in your arm – I have never seen. Although computer transistor circuits are a possible (non-biological) candidate.

• Very interesting question. And yes, as Harry above just said, I agree with him – the brain is really what does the thinking / complex reasoning. – Miss_Lara13385 Aug 8 '16 at 17:24
• Hi Harry, first of all welcome at CogSci and thank you for your answer. I was wondering though if you have any references to back up your claims. Here at CogSci we are looking to build a knowledge databases with well researched and referenced answers. Thank you in advance :) – Robin Kramer Aug 8 '16 at 17:37
• To Robin: ok - i made an edit to add some references. – Harry Muzart Aug 8 '16 at 18:31

If, as Harry said, we think only with our brains, the neuroscientist Antonio Damasio wrote about the importance of the body in rational thinking in his book Descartes' Error.

His hypothesis is that the brain continuously computes all informations (state, activity...) coming from our organs $-$ informations which he called "somatic markers" $-$ and thus, the decisions our brains make are biased by these informations. In particular, somatic markers help a lot to discriminate non-relevant "thoughts" or potential decisions.

The book is called "Descartes' Error" because Descartes thought he had to get rid of his feelings to be able to think rationally. Damasio thinks, in the contrary, that feelings help to do so.

I hope this answer complete Harry's one, by showing that if only the brain is capable of thinking, organs are necessary anyway (according to Antonio Damasio at least).

• To be fair, the body is a source of sensory input in the same way as visual, auditory, etc. So it's not really a special source of influence on the brain. – mrt Aug 18 '16 at 21:25

I just want add / clarify something on top of Aika’s answer – I want to say that Damasio’s work does not contradict what I said. This is another big misunderstanding. All our feelings and bodily sensations are a product of the brain, even if the information if initially processed in the peripheral nervous system. Yes, peripherally-computed sensory information is vital to cognitive systems, but it is the brain that integrates all this to construct and simulate somatic marker sensations and rational thinking for complex decision-making. We could theoretically take away all peripheral nerves from the brain and replace them with wires to then input any information we want, to then simulate any type of thought we want in that brain. Unfortunately, while there has been some recent experiments in that, we are very far from that technology.