An Automatic Valuation System in the Human Brain: Evidence from Functional Neuroimaging. Lebreton, Jorge, Michel, Thirion, Pessiglione. Neuron 2009.

  1. fMRI study on brain areas involved in making decisions of preference
  2. Does the brain activate the value system under all circumstances or only when a decision is to be made?
  3. Limbic frontostriatal circuits have been implicated in both valuation and choice tasks, this region includes:
    1. Ventral prefrontal cortex
    2. Amygdala
    3. Hippocampus
  4. Although these areas have been identified, the studies involve tasks where valuation is actively occurring.  This work examines the case where valuation isn’t explicitly part of the task
  5. Study is also unique in that it involved items of different categories
  6. At first subjects were asked either to rank a face according to age or pleasantness.  After this pairs of faces were shown, and a preference was to be indicated
  7. Data shows no correlation between predictions of age and assigned pleasantness (orthogonal)
  8. Pictures were based on rating basically neutrally pleasant
  9. The same set of pairs of pictures were shown to each subject
  10. Each picture was shown once in an easy comparison and once in a hard comparison
  11. Agreement was about 75% for “easy” comparisons and 70% for “hard”
  12. When assessed a month later the selections made were very stable
  13. “Harder” decisions took longer
  14. Different categories of stimuli activated different brain regions
  15. “… two dimensions to be rated in the different tasks (age and pleasantness ratings), thus yielded significantly different activations.”
  16. Brain valuation system (BVS) as discussed includes:
    1. VMPFC
    2. VS
    3. hippocampus
    4. PCC
  17. BVS measured matches the individual and not the average scores for any face
  18. BVS was shown to encode preference values for many different types of objects, not just faces
  19. BVS signal showed up even when the task did not involve preference ranking
  20. “Our results provide a confirmation of previous studies that characterized limbic fronto-striatal circuits as a valuation system.”
  21. “… the so-called limbic or affective circuit generally  including the amygdala, hippocampus, and ventral prefrontal cortex as the main inputs to the ventral-basal ganglia circuit (VS, ventral pallidum, ventral tegmental area, and medio-dorsal thalamus).  Considerable evidence from both human and nonhuman species supports the idea that the limbic circuit is involved in reward processing.”
  22. “Here, we found that at least three components of the limbic circuit, the hippocampus, VS, and VMPFC, reflected subjective values assigned to visual items that are not universal rewards such as food or money.”
  23. “Our BVS also included the PCC [posterior cingulate cortex?], which may be less expected, as the PCC has been implicated, together with the hippocampus, in episodic and autobiographic memory. … although PCC activation is in fact frequently reported in preference studies…”
  24. “… decision making might be based on values linearly encoded in the BVS.”
  25. They didn’t scan during the binary choice part of the experiment
  26. “… giving money to a charity have been found to activate these [BVS] regions just as more basic rewards like receiving money or food do.”

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