Possible Role of the Pineal Gland in the Human Memory System.

Purpose: Pineal Gland (PG) is a midline brain structure and part of the epithalamus, a dorsal posterior segment of the diencephalon. Most findings on the role of this structure in brain function are relevant to melatonin secretion, and only a few reports are available on its involvement in brain cognition. Materials and Methods: Due to some suggestions on the role of the diencephalon areas, including the PG, in the human memory system, we used data from two previous MRI studies on 32 and 295 healthy individuals, in order to identify first, if the PG shows activations in fMRI and during a memory retrieval task as well as showing functional connectivity with other brain structures, and second, if there are any associations between the PG volume and the memory scores of the individuals. Results: Using a standard PG atlas, our results showed significant activations in PG during memory retrieval, with the strength of these activations increasing with the increment of the cognitive load of the task. Also, PG showed functional connectivity with other brain structures during fMRI, the pattern of which also changed with the cognitive load of the retrieval. Finally, the volume of the PG showed significant associations with the scores of the memory tests. Conclusion: Our knowledge of the PG still needs improvement, and we hope our findings here could be a help for that as well as a help to better understand the mechanisms of memory storage and retrieval in humans. [ABSTRACT FROM AUTHOR]