Why there are complementary learning systems in the hippocampus and neocortex: insights from the successes and failures of connectionist models of learning and memory.
The account presented here suggests that memories are first stored via synaptic changes in the hippocampal system, that these changes support reinstatement of recent memories in the neocortex, that neocortical synapses change a little on each reinstatement, and that remote memory is based on accumulated neocorticals changes.
Theta phase precession in hippocampal neuronal populations and the compression of temporal sequences
Large‐scale parallel recordings are made use of to clarify and extend the finding that a cell's spike activity advances to earlier phases of the theta cycle as the rat passes through the cell's place field, and to show Granule cells of the fascia dentata are also modulated by theta.
Reactivation of hippocampal ensemble memories during sleep.
Recordings from large ensembles of hippocampal "place cells" in three rats showed that cells that fired together when the animal occupied particular locations in the environment exhibited an increased tendency to fire together during subsequent sleep, in comparison to sleep episodes preceding the behavioral tasks.
Path integration and the neural basis of the 'cognitive map'
- B. McNaughton, F. Battaglia, O. Jensen, E. Moser, M. Moser
- Biology, PsychologyNature Reviews Neuroscience
- 1 August 2006
Theoretical studies suggest that the medial entorhinal cortex might perform some of the essential underlying computations by means of a unique, periodic synaptic matrix that could be self-organized in early development through a simple, symmetry-breaking operation.
Conjunctive Representation of Position, Direction, and Velocity in Entorhinal Cortex
The conjunction of positional, directional, and translational information in a single MEC cell type may enable grid coordinates to be updated during self-motion–based navigation.
Dynamics of the hippocampal ensemble code for space.
Parallel recording methods outlined here make possible the study of the dynamics of neuronal interactions during unique behavioral events, which suggests that new spatial information creates conditions in the hippocampal circuitry that are conducive to the synaptic modification presumed to be involved in learning.
Environment-specific expression of the immediate-early gene Arc in hippocampal neuronal ensembles
Following sequential exposure of rats to two different environments or to the same environment twice, the proportion of CA1 neurons with cytoplasmic, nuclear or overlapping Arc expression profiles matched predictions derived from ensemble neurophysiological recordings of hippocampal neuronal ensembles.
Path Integration and Cognitive Mapping in a Continuous Attractor Neural Network Model
The model provides an explanation for a number of hitherto perplexing observations on hippocampal place fields, including doubling, vanishing, reshaping in distorted environments, acquiring directionality in a two-goal shuttling task, rapid formation in a novel environment, and slow rotation after disorientation.
Deciphering the hippocampal polyglot: the hippocampus as a path integration system.
A hypothesis of how the path integration system may operate at the neuronal level is proposed, and it appears that viewpoint-specific visual information becomes secondarily bound to this structure by associative learning.
Reactivation of Hippocampal Cell Assemblies: Effects of Behavioral State, Experience, and EEG Dynamics
Pattern reinstatement was strongest during sharp wave–ripple oscillations, suggesting that these events may reflect system convergence onto attractor states corresponding to previous experiences, and do not necessarily reflect persistence of an active memory.