How the brain computes space - and how places invade memories
Ingvild Ulsaker Kruge PhD student Kavli Institute for Systems Neuroscience/ Center for Neural Computation
Arkitektstudentene ntnu.edu/kavli 8. mars 2016 TODAY:
1) Amnesia, memory loss
2) The hippocampal formation and spatial navigation
3) How places invade our memories
ntnu.edu/kavli A whole field of research was born from the misfortunes of one man… ’Loss of recent memory after bilateral hippocampal lesions’ (Scoville & Milner 1957)
Human brain, bottom-up view
Human brain, coronal view H.M. (1926-2008) Henry Gustav Molaison
ntnu.edu/kavli ”…there has been one striking and totally unexpected behavioral result: a grave loss of recent memory.” ”After operation this young man could no longer recognize the hospital staff nor find his way to the bathroom, and he seemed to recall nothing of the day- to-day events of his hospital life.” For the next 55 years, each time he met a friend, each time he ate a meal, each time he walked in the woods, it was as if for the first time.
Scoville & Milner, 1957
W.B. Scoville B. Milner W.G. Penfield
ntnu.edu/kavli Clive Wearing pianist, composer, father and husband Suffered catastrophic amnesia after Herpes virus infection
https://www.youtube.com/watch?v=Vwigmktix2Y
ntnu.edu/kavli
The Man With The 7 Second Memory ITV1
«It’s been like death. I’ve never seen a human being before. Never had a dream or a thought. The brain’s been totally inactive. Day and night the same. No thought at all.» - Clive Wearing
ntnu.edu/kavli What can we learn from patients like Clive and HM? There are several forms of memory
Conscious Unconscious
Clive and HM
ntnu.edu/kavli What can we learn from patients like Clive and HM? The hippocampal formation is necessary to form new, episodic memories
ntnu.edu/kavli ntnu.edu/kavli http://www.brightstarcare.com/chattanooga/files/2013/11/alzheimers-scan.jpg Size doesn’t always matter
ntnu.edu/kavli Different brains, but a conserved cortical architecture
ntnu.edu/kavli Hippocampus in rodents is very similar to our hippocampus
ntnu.edu/kavli 150 years ago: Today: Drawing by Camillo Golgi of a hippocampus stained using the silver nitrate method
Otto Deiters' drawing of a neuron, published in 1865.
Dentate gyrus, part of the hippocampus, in mice. Jeff Lichtman via Luis de la Torre-Ubieta, Geschwind Laboratory, UCLA, CC BY-NC-ND 4.0, Wellcome Images Center for Brain Science Camillo Golgi's drawing of a dog's olfactory bulb, 1875. https://www.braindecoder.com/a-visual-history-of-neurons-1089282606.html In our lab, we see and hear how brain cells communicate
”mikrofon”
Micro electrodes can be used as a miniature microphone to listen to and register electrical activity/action potentials from brain cells.
ntnu.edu/kavli John O’Keefe
Target location in dorsal CA3
Laura Colgin, Kavli Institute for Systems Neuroscience, ntnu.edu/kavli now University of Texas at Austin REMAPPING = different brain maps for different places and experiences
Colgin, Moser & Moser, 2008 ntnu.edu/kavli Grid cells = a metric for space Based on calculations of neural networks deep within the brain, far from sensory cortices
ntnu.edu/kavli The tesselating grid fields may function as longitude and latitude in a map
ntnu.edu/kavli How can you know where you are?
Entorhinal cortex
Hippocampus
ntnu.edu/kavli Hippocampus and EC = At the top of a hierarchi
Integrate information from all the senses (not only vision)
Felleman, D.J. and Van Essen, D.C. (1991) Distributed hierarchical processing in primate visual cortex. Cerebral Cortex, 1: 1-47 ntnu.edu/kavli
How spaces and places invade our memories?
ventral visual stream dorsal visual stream
perirhinal cortex parahippocampal cortex
lateral entorhinal cortex medial entorhinal cortex
hippocampus hippocampus
Eichenbaum et al 2007, Medial temporal lobes and recognition memory
ntnu.edu/kavli Build your own memory palace = improve your memory instantaneously! Associations
Images/faces
Emotions
NATURE OR NURTURE?
camera
infrared
with Filmed
ntnu.edu/kavli ntnu.edu/kavli ntnu.edu/kavli Grid cell periodicity substantially reduced over several days
The data suggest that grid cells are sensitive to experience with environmental references and boundaries during the first postnatal weeks
Kruge et al.,unpublished ntnu.edu/kavli 1) Amnesia, memory loss
2) Hippocampal place cells, entorhinal grid cells
3) Our internal map of space is important for survival and memory!
4) Grid cells require experience with local boundaries during development ntnu.edu/kavli TAKK FOR MEG!
Bidrag fra: May-Britt og Edvard Moser, John O’Keefe, Menno Witter, Laura Colgin, Marianne Fyhn, Torkel Hafting, Vegard Brun, Kirsten Kjelstrup, Trygve Solstad, Francesca Sargolini, Jonathan Whitlock, Hanne og Tor Stensola, + Sølvreven, Lasse og Geir, m.fl.
[email protected] Støtte fra: Kavli Foundation, Forskningsrådet, European Research Council, NTNU ntnu.edu/kavli