spatial and temporal representations in the hippocampal memory system Flashcards
•Many neurons in rodent hippocampus have receptive fields that represent spatial locations (“place cells” with “place fields”) •Hippocampal neurons in other mammals and in pigeons also show spatial specificity •Some neurons in mammalian medial entorhinalcortex show other types of spatial representations: grid cells, border cells, and head direction cells •There is a distributed place, grid, head direction cell system •Place cells respond to more than place •Spatial memory or memory space?
example of place cells in rats, bat, human and pigeon
random foraging task
experiment showing place cells are sensitive to visual inputs
experiment: light on/off
some cells responded the same in both conditions, some not
using visual condition for spatial orientation
conclusion: visual cue is one of the factors affecting spatial, but not the only one
gradient of spatial scaling along hippocampus
small/medium/large place fields
cells are direction-selective at the dorsal side, but less selective when switch to ventral side
slide 24
place cell firing during REM and NREM sleep
NREM burst replay is coordinated between cortex and hippocampus
NREM: mutl-unit burst; tends to fire follow the sequence during the awake period
grid cells in rat medial entorhinal cortex, bats
indicated by rate map and spatial autocorrelogram
place cells from overlapping points of grid cells?
:)
stimuus-response (S-R, left/right) learning or cognitive map (S-S learning, west/east)
T-maze training
place cells respond to more than one place
some hippocampal neurons respond to nonspatial stimuli
cognitive map: spatial memory or memory space?
object representations in hippocampus were location-dependent;
hippocampal cognitive map encodes locations and the point of interest at those locations
place cells gradually change over time
Mann’s experiment
time cell
running on treadmill experiment
