The SEEKING System: The Brain’s Reward Pathway?

This is the first in my series on the neuro-evolutionary origins of emotions. A theory proposed by the late Jaak Panksepp in his book The Archaeology of the Mind. See here and here for my intros into the neuro-evolutionary origins of emotions.

“When I’m down by more than $100, that’s when I start to get really crazy. I won’t stop, no matter how much I lose, until I get a decent win, of say one to two hundred. It’s completely illogical because I usually put so much more into the machine than I end up winning. My brain is just chasing that hit of dopamine no matter the cost”.

Ryan*, a problem user of poker machines

Brain Zapping your Way to Happiness

In 1953, Psychologist James Olds and Neuroscientist Peter Milner zapped the brains of some rats. Specifically, they electrically stimulated the rodents’ Medial Forebrain Bundle-Lateral Hypothalamic Area (MFB-LH). Olds and Milner found that stimulating this area was “highly reinforcing” – that is, rats would quickly learn to repeat any behaviour that would lead to stimulation. The rats had become zap addicts!

Soon, all sorts of researchers were conducting similar experiments. Interesting (and creepy) experiments involved “self-stimulation”, where human subjects (who have similar enough brain to rats) were given the opportunity to press a button to stimulate their own brain. These subjects would neglect their personal care and basic needs in order to simply continue stimulating. Animals given the self-stimulation option would often button press to the point of starvation, dehydration and death.

Based on research like this, the MFB-LH associated pathways have been popularly named the Reward Pathway. These pathways, which are strongly associated with the neurotransmitter, dopamine, are now firmly in the public consciousness. Many clients, including Ryan mentioned above, will talk in terms of their chase for dopamine as a way to explain their addictive behaviours.

And this pathway is very much associated with addiction. The behaviour of those addicted to poker machines shows a direct parallel to the self-stimulating human guinea pigs. Many illicit drugs, particularly stimulants such as cocaine and ice (methamphetamine), directly activate this pathway.

Manic episodes, a key feature of bipolar disorder, also involve these dopamine-based pathways. As do, psychotic episodes, which are a hallmark of schizophrenia.

Conversely, during an episode of depression, pleasure seeking behaviours are severely reduced. Motivation loss, flat mood and anhedonia (a generalised lack of pleasure) are all key symptoms of depression. The “reward pathway” often demonstrate a lack of activation in those with a depressive disorder.

Appetite or Consumption?

So just how pleasurable is the reward pathway?

Interestingly, there are many regions of the brain which deliver highly pleasurable feelings when electrically stimulated. People who self-stimulate these other areas often go back for more, but they don’t display the same addictive/compulsive pattern as when stimulating the reward pathway. The reward pathway is especially active during the hunt for a reward. But it actually diminishes in strength when the reward is consumed.

Because of evidence like this, Neuropsychologist Jaak Panksepp, challenges the Reward Pathway label. In Panksepp’s view, what defines these MFB-LH-related pathways is that they create an excitable seeking or expectation urge. He labelled this system the SEEKING system to reflect that the pathways are more associated with appetite than consumption.

For example, take Ryan:

“It’s not that I feel necessarily good when I’m playing. I’m just zoning out. I sometimes lose track of time. When I win it’s a relief, but I pretty quickly feel guilt and shame if I know if lost a lot in the lead up to that”.   

The SEEKING system is at work while we are chasing, hunting, searching for a reward. It is a motivational state that allows us to continue performing an activity which we expect will result in a reward. The reward we chase could be a natural pleasure such as food, water or sexual activity. Or, especially in humans, it could be a learnt reward, like money, mastery over a task, learning or admiration from others.

The main point is that the SEEKING system directs us to get a reward but it is not the reward itself.

Our Emotional Life

Which human emotions most closely match the SEEKING System?

Excited happiness seems to match the reports of this system given by self-stimulators and stimulant drug users. However happy feelings that are more akin to warm connection to others are less likely to match the SEEKING sensations. Likewise, feelings of peace and tranquillity would not match this system.

Feelings associated with the competitive struggle are likely associated with the SEEKING system. These competitive feelings might be described as thrill, adventure and fun.

Panksepp notes that in animals looking for a safe refuge from danger, the SEEKING System becomes enacted. Also, a very hungry animal searching for food will have a highly activated SEEKING System. Evidently then, the SEEKING system is not always associated with positive emotions. It could be experienced as anxiety or frustration.

SEEKING and the Human Tragedy

I feel that Panksepp’s description of the SEEKING system is an apt descriptor of the feelings associated with addictive and compulsive behaviours. It explains why people like Ryan spend so much time on an activity which produces mainly (non-pleasurable) losses, rather than on something which more reliably produces pleasurable wins. It explains why heroin addicts often tell me that procuring drugs and setting up the hit is half the appeal of the drug itself (unlike stimulants, heroin is not a substance that highly activates this pathway).

The de-activation of the SEEKING system provides an interesting explanation for many depressive episodes. Flat mood, hopelessness and low motivation are more significant features of depression than sad mood.

The focus on the motivational nature of the SEEKING system, rather than on the reward, helps to explain why we humans spend so much time striving for rewards relative to actually enjoying the rewards themselves. We feel more of a pull to be in the SEEKING state than to the satisfied state. The SEEKING system gives a compelling explanation for this aspect of the human tragedy.