We have a fridge full of human brain tissue: containers upon containers stacked one on top of the other, each filled nearly to the brim with floating segments of formalin soaked tissue. Each one holds segments of one individual-- possibly a non-dementia affected control, or a Parkinson’s (PD) and/or Alzheimer’s disease (AD) affected tissue. The glass is labelled as such: control, PD, AD, or PD + AD, as well as for how many years the person was affected, the date the brain was received, all the days and times it was fixed so that the tissue remains preserved, and an ID-- the series of three letters starting with ‘R.’ In the image below, the pink taped container in the top center has been preserved since 1995.
Of particular interest is a small group of neurons called the Nucleus basalis of Meynert (nbM), located in the basal forebrain (see image below). It is part of what is called the cholinergic system, a neurotransmitter system that uses acetylcholine to transmit nerve impulses. The system projects throughout the neocortex and the hippocampus of the brain (again, see image below), and is involved with memory, learning, and arousal. “[N]euronal loss within the cholinergic nucleus basalis of Meynert (nbM) correlates with cognitive decline in dementing disorders such as Alzheimer’s disease (AD)” (Liu, Chang, Pearce, & Gentleman, 2015). The Mufson lab hopes to discover more.
The container below was once very full of tissue, however multiple segments have been removed and dissected.
The scientist-- an expert in neuroanatomy-- lays the pieces out on the bench and cuts out particular sections to be sliced and mounted onto slides to be studied.
The fridge contains upwards of 200 of these containers, arranged in alphabetical order, and the lab is constantly retrieving different ones to collect particular segments of the brain they wish to study.
Of particular interest is a small group of neurons called the Nucleus basalis of Meynert (nbM), located in the basal forebrain (see image below). It is part of what is called the cholinergic system, a neurotransmitter system that uses acetylcholine to transmit nerve impulses. The system projects throughout the neocortex and the hippocampus of the brain (again, see image below), and is involved with memory, learning, and arousal. “[N]euronal loss within the cholinergic nucleus basalis of Meynert (nbM) correlates with cognitive decline in dementing disorders such as Alzheimer’s disease (AD)” (Liu, Chang, Pearce, & Gentleman, 2015). The Mufson lab hopes to discover more.
Citations
Liu, A. K., Chang, R. C., Pearce, R. K., & Gentleman, S. M. (2015). Nucleus basalis of Meynert revisited: anatomy, history and differential involvement in Alzheimer’s and Parkinson’s disease. Acta Neuropathologica, 129(4), 527-540. doi:10.1007/s00401-015-1392-5
Hi Anila! Wow, it looks like such an interesting internship so far! I see that you mentioned that one of the samples of brain tissue has been preserved since 1995...How long can a sample be preserved without compromising the tissue? It's so impressive to think we can study brain tissue from 1995!
ReplyDeleteThe sample can be preserved virtually forever! As long as it remains in the fixing and cryoprotectant solution that prevents it from freezing and is in the 4 degree fridge, it can be viable for use in the lab eternally.
ReplyDelete