For Those Who Need or Want To Know More
DLPFC - Dorsolateral Prefrontal Cortex
Dorsal = upper part
Lateral = to the side
Prefrontal = That part of the frontal lobe which receives thalamic projections from the mediodorsal nucleus (Woolsey 1947)
Cortex = from the Latin word for "bark" the outside layer of the cerebrum, cortex is gray matter meaning it is composed of cells as opposed to the white matter underneath
One hundred years ago a psychiatrist in Germany (Paul Flechsig, MD (1847-1929) noticed that the cortex did not all myelinate at the same time, but developed in a certain sequence which appeared analogous to the evolution of the brain. The first parts of the brain which myelinates we share with the most primitive mammals, these are the basic input-output areas of face, arms, legs etc. The last to develop are those areas which make us the most human - the "Higher Functions" such as creativity, intelligence, memory, planning and sequencing. He numbered the areas and made a map of the brain from area 1 to 45.
This map of the brain points us to pay attention to the Dorsolateral Prefrontal Cortex (Flechsig #45, Brodmann's areas 9 & 46) and the Frontal Pole (Flechsig #45, Brodmann's area 10).
In the century that followed, this last area has been studied extensively.
Development of white matter with increasing age in the right DLPFC (myelinogenesis). This graph demonstrates the correlation between age and myelination of the white matter (axons) (reflected in level of fractional anistotropy (FA) (Barnea-Goraly et al., 2005)
Fig. 3. The influence of left dorsolateral prefrontal cortex (DLPFC) on the correlated activity between the dorsomedial midbrain and medial thalamus during heat allodynia. Upper right graph shows the negative correlation between activity in the left DLPFC and each subject’s rating (VAS) of pain unpleasantness during heat allodynia. A median split of DLPFC activity defines high (filled circles) and low (open circles) activity levels. The lower right graph shows the strong positive midbrain-thalamic correlation when DLPFC activity is low and a lack of significant correlation when DLPFC activity is high. The diagram (left) summarizes one interpretation of this relationship. Midbrain and medial thalamic activity are uniquely activated during heat allodynia, which is associated specifically with increased pain unpleasantness (compared to normal heat pain). The left DLPFC, while also activated in this condition, is negatively correlated with pain unpleasantness. Our analysis of these results is consistent with the interpretation that the left DLPFC actively reduces pain unpleasantness (affect) by reducing the activity ascending from the midbrain to medial thalamus during heat allodynia.
From - Casey, Lorenz & Minoshima 2003 Insights into the pathophysiology of neuropathic pain through functional brain imaging