Oxford University researchers have discovered that learned knowledge is stored in different brain circuits depending on how we acquire it.
The researchers from the Department of Experimental Psychology, the Wellcome Centre for Integrative Neuroimaging (WIN) and the Nuffield Department of Clinical Neurosciences, used an MRI scanner to observe changes in parts of the brain associated with learning and learned experiences while volunteers completed tasks that involved a reward.
Participants also attended two sessions prior to scanning to compare their individual associations between stimulus sequences and reward.
They found that the changes seen in the participants’ neural pathways associated with learning were different depending upon how each person had learned the new skill.
Miriam Klein-Flugge of the Department of Experimental Psychology, said: ‘We know that humans can learn in different ways. Sometimes we learn simply by observing relationships in the world, such as learning the layout of a new town, or relationships between people.
But another way to learn is by setting particular goals, like children learning to operate toys by trial and error.
They found that the changes seen in the participants’ neural pathways associated with learning were different depending upon how each person had learned the new skill. The image is adapted from the Oxford University news release.
‘This research shows that we have multiple networks in the brain that help us store learned knowledge or associations, which means that damage to one part of the brain will still leave alternative mechanisms available for learning.
‘We also learned that some of this knowledge is very persistent, and the brain does not forget about it even when it becomes irrelevant, while knowledge acquired through alternative learning mechanisms is more flexible and can more easily be changed to new knowledge.’
As well as showing that the brain can learn in different ways and that these multiple mechanisms for learning rely on the concerted effort of multiple different brain networks, the study also showed that unlearning associations can be easier when they were acquired by observation compared to a goal-directed manner.
Miriam Klein-Flugge added: ‘It is well known that it is good for our brains to continue to learn new things throughout life, which is why understanding the different ways in which we learn and store knowledge could be beneficial and help each of us to find out which way of learning suits us best.’
This article reviews the structural and functional changes in pain chronification and explores the association between memory and the development of chronic pain.
PubMed was searched using the terms “chronic pain,” “central sensitization,” “learning,” “memory,” “long-term potentiation,” “long-term depression,” and “pain memory.” Relevant findings were synthesized into a narrative of the processes affecting pain chronification.
Pain pathways represent a complex sensory system with cognitive, emotional, and behavioral influences.
Anatomically, the hippocampus, amygdala, and anterior cortex-central to the encoding and consolidation of memory-are also implicated in experiential aspects of pain.
Common neurotransmitters and similar mechanisms of neural plasticity (eg, central sensitization, long-term potentiation) suggest a mechanistic overlap between chronic pain and memory.
These anatomic and mechanistic correlates indicate that chronic pain and memory intimately interact on several levels.
Longitudinal imaging studies suggest that spatiotemporal reorganization of brain activity accompanies the transition to chronic pain, during which the representation of pain gradually shifts from sensory to emotional and limbic structures.
The chronification of pain can be conceptualized as activity-induced plasticity of the limbic-cortical circuitry resulting in reorganization of the neocortex.
The state of the limbic-cortical network determines whether nociceptive signals are transient or chronic by extinguishing pathways or amplifying signals that intensify the emotional component of nociceptive inputs.
Thus, chronic pain can be seen as the persistence of the memory of pain and/or the inability to extinguish painful memories. Ideally, pharmacologic, physical, and/or psychological approaches should reverse the reorganization accompanying chronic pain.
Miriam Klein-Flugge – Oxford University
The image is adapted from the Oxford University news release.
Original Research: Open access
“Multiple associative structures created by reinforcement and incidental statistical learning mechanisms”. Miriam C. Klein-Flügge, Marco K. Wittmann, Anna Shpektor, Daria E. A. Jensen & Matthew F. S. Rushworth.
Nature Communications doi:10.1038/s41467-019-12557-z.