"The prosperous husband and the poor, the happy extreme is the sad"-the role of the hypothalamus in food rewards and drug rewards

Author | Liu Ying Xu Xing said in ancient times, "Hungry comes to eat, sleepy comes to sleep"
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The basic natural law of eating and sleeping is the instinctive behavior on which survival depends.
The occurrence of this instinctive behavior is driven by the demand for energy metabolism and reward experience
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In today's social environment, people work hard for a better life.
While struggling, pressure is always with them
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The first cup of milk tea in autumn, delicious cakes, the newly opened hot pot restaurant downstairs, "Summoners Canyon half-day tour", bar clubs and other entertainment activities have generally become everyone's favorite ways of decompression
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Why are there so many types of entertainment? In fact, this is a positively motivated behavior that people show in the face of pressure
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But are these decompression methods healthy? Can it be decompressed for a long time? The truth about decompression People's preferred decompression method, whether it is food or entertainment, can stimulate the large release of dopamine (DA) in the brain and bring a pleasant feeling, so it can decompress
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But the same way of decompression, over time, will unconsciously increase food intake or entertainment time
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For example, when you are brushing various short video software, you will continue to increase the surfing time, and there will always be a new video waiting for you
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Why can't we stop? To some extent, this may be because our body's reward has changed, which makes the body no longer satisfied with the original reward effect, thus affecting our behavioral decision-making
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In this process of change, the energy steady-state system and the reward system play a major role.

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If rewards are divided into degrees, then from general food, gourmet and entertainment activities to addictive drugs, it can be considered that the reward effect is increasing
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Feeding behavior under physiological conditions is a motivational behavior for the purpose of satisfying instinctive needs.
When this intrinsic motivational behavior is "held" by the reward effect, it will cause pathological changes, such as obesity, which is also called "food".
Addiction” means that even if the body is full, it still chooses to consume food continuously based on the motivation of food reward experience[1]; and drug-induced addictive behavior is due to the strong rewarding effect of drugs, leading to decentness of the body Motivation is enhanced when taking drugs, and the acquisition of drugs cannot be controlled
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For food and entertainment activities, they are somewhere between natural rewards and drug rewards, but as pressure increases and time passes, they may also have a certain chance to develop into uncontrollable "addiction"
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At present, in addiction research, there is still an unsolved problem: Does the nature of seeking drugs and natural rewards have the same neurobiological mechanism? Therefore, in order to have a better life and balance the physical and psychological needs, we need to have a deep understanding of how the brain guides behavior in the face of rewards
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From Volkow, Wang, Tomasi, & Baler, 2013 Reward under normal motivation-"Happy" motivational behavior is produced by internal needs (hunger, sleep, thirst, etc.
) and externally induced stimuli (food, addictive substances, etc.
) The impact of [2] is to meet their own needs
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Reward-related behaviors mediated by DA, including food intake and drug abuse [3]
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Although the findings of the research on feeding behavior mainly focus on weight management, energy expenditure and food intake, the brain area is mainly the hypothalamus [4]; but because of the close relationship between feeding and reward [5], the neural mechanism of feeding The research also started from the reward-related behaviors, focusing on the neural circuits or DA neurons from the ventral tegmental area (VTA) of the midbrain to the nucleus accumbens (NAc)[6]
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Therefore, it can be considered that the regulation of feeding behavior depends on the interaction between the homeostasis-related melanocortin (MC) system and the reward-related DA system [7]
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The MC system contains two types of neurons that have opposite functions in the regulation of feeding, namely proopiomelanocortin (POMC) neurons that inhibit eating and agouti-related protein (AgRP) neurons that promote eating Yuan [8]
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During the feeding process, the neurotransmitters and neuropeptides released by POMC neurons and AgRP neurons act on the corresponding receptors on VTA neurons, dynamically adjust the activity of DA neurons, and control the completion of feeding behavior [9]
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Reward under abnormal motives-"sorrow" based on positive reinforcement of rewards is a common evolutionary survival strategy across species
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However, in drug addiction, this strategy of seeking positive rewards will change, and it will even affect life and health seriously
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Due to the close neural connection between the hypothalamic MC system (the regulatory center of feeding behavior) and the midbrain DA system (the common target of addictive drugs) [10], in the process of drug abuse, rewards, motivation and other behaviors mainly depend on DA The midbrain reward loop that the system participates in, as research continues to deepen, it is found that addictive drugs will also affect the activity of hypothalamic POMC neurons and AgRP neurons in the MC system [4]
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Under normal conditions, POMC neurons and AgRP neurons in the hypothalamus have a balancing effect.
Individuals can obtain appropriate rewards through motivation-mediated feeding behavior and stop in time; however, when the balance mechanism between the two is broken, Individuals may exhibit abnormal enhancement of motivation and abnormal reward-obtaining behavior, such as compulsive drug-seeking behavior
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The balance of "happiness" and "sorrow" So, what is the relationship between motivational behavior and reward feeling? Does the MC system of the hypothalamus and the DA system of the VTA regulate the occurrence of reward-related motivational behaviors through feedback interaction? Is the drug addiction process the result of the above-mentioned pathological changes in the neural network, leading to the "usurpation" of instinctive behavior? These questions are the thinking directions for studying abnormal reward intake behaviors such as drug addiction, overeating and obesity
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In future research, the formation of addiction can be deeply explored from the internal balance mechanism of POMC neurons and AgRP neurons in the MC system (for details, please click below to read the original text)
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In life, we must relax and be content, so that we can keep our body and mind healthy while getting relief
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References: 1.
Filbey FM, Myers US, Dewitt S.
Reward circuit function in high BMI individuals with compulsive overeating: similarities with addiction.
Neuroimage, 2012, 63(4): 1800-18062.
Kalivas PW, Volkow N D.
The neural basis of addiction: a pathology of motivation and choice.
Am J Psychiatry, 2005, 162(8): 1403-14133.
Volkow ND, Wise RA, Baler R.
The dopamine motive system: implications for drug and food addiction.
Nat Rev Neurosci, 2017, 18(12): 741-7524.
Zeltser LM, Seeley RJ, Tschöp M H.
Synaptic plasticity in neuronal circuits regulating energy balance.
Nature Neuroscience, 2012, 15(10): 1336-13425.
Rossi MA, Stuber G D.
Overlapping brain circuits for homeostatic and hedonic feeding.
CellMetab, 2018, 27(1): 42-566.
Edwards NJ, Tejeda HA, Pignatelli M, et al.
Circuit specificity in the inhibitory architecture of the VTA regulates cocaine-induced behavior.
Nat Neurosci, 2017, 20(3): 438-4487.
Koch M, Horvath T L.
Molecular and cellular regulation of hypothalamic melanocortin neurons controlling food intake and energy metabolism .
Mol Psychiatry, 2014, 19(7): 752-7618.
Sohn JW, Elmquist JK, Williams K W.
Neuronal circuits that regulate feeding behavior and metabolism.
Trends Neurosci, 2013, 36(9): 504-5129.
Shanmugarajah L , Dunigan AI, Frantz KJ, et al.
Altered sucrose self-administration following injection of melanocortin receptor agonists and antagonists into the ventral tegmental area.
Psychopharmacology (Berl), 2017, 234(11): 1683-169210.
Dileone RJ, Taylor JR , Picciotto M R.
The drive to eat: comparisons and distinctions between mechanisms of food reward and drug addiction.
Nat Neurosci, 2012,15(10): 1330-1335 Ying Liu, Institute of Psychology, Chinese Academy of Sciences, current research direction is the brain mechanism of drug addiction
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Xu Xing Institute of Psychology, Chinese Academy of Sciences, whose main research direction is the neural circuit mechanism of social rewards and the pathogenesis of autism
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