Hippocampal theta sequences

@article{citeulike:1525368, abstract = {The activity of individual hippocampal principal neurons is spatially localized such that each neuron is active only when the animal occupies an area of the environment known as the cell's place field. Additionally, the activity of hippocampal neurons exhibits a particular temporal relationship to the hippocampal EEG, such that spikes fired by the neuron occur at progressively earlier phases of the co-occurring theta rhythm in the EEG as the animal traverses the place field. This relationship is known as theta precession. A long-standing prediction following the observation of theta precession has been that among a collection of hippocampal neurons recorded simultaneously, the neurons will fire in sequences reflecting the behavioral order of the place fields. Here we examine this prediction. We show that clear, ordered sequences occur during theta, which we name theta sequences, in which a portion of the animal's spatial experience is played out in forwards order. We further investigate the relationship of theta sequences to phase precession by shuffling spike phases in such a way as to preserve the relationship between spike phase and position. This jitter significantly reduces the prevalence of theta sequences while leaving theta phase precession intact, suggesting that the presence of theta phase precession is not trivially predictive of theta sequences. Finally, we discuss the relationship between theta sequences and individual place fields, and the possible functional role of theta sequences in navigational learning. {\copyright} 2007 Wiley-Liss, Inc.}, address = {Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, Massachusetts; Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts; RIKEN-MIT Neuroscience Research Center, Massachusetts Institute of Technology, Cambridge, Massachusetts}, author = {Foster, David J. and Wilson, Matthew A. }, citeulike-article-id = {1525368}, doi = {10.1002/hipo.20345}, journal = {Hippocampus}, keywords = {theta}, number = {9999}, pages = {NA+}, posted-at = {2008-01-09 19:59:12}, priority = {2}, title = {Hippocampal theta sequences}, url = {http://dx.doi.org/10.1002/hipo.20345}, volume = {9999}, year = {2007} }

TY - JOUR ID - citeulike:1525368 L3 - citeulike-article-id:1525368 TI - Hippocampal theta sequences JF - Hippocampus VL - 9999 IS - 9999 SP - NA AD - Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, Massachusetts; Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts; RIKEN-MIT Neuroscience Research Center, Massachusetts Institute of Technology, Cambridge, Massachusetts N2 - The activity of individual hippocampal principal neurons is spatially localized such that each neuron is active only when the animal occupies an area of the environment known as the cell's place field. Additionally, the activity of hippocampal neurons exhibits a particular temporal relationship to the hippocampal EEG, such that spikes fired by the neuron occur at progressively earlier phases of the co-occurring theta rhythm in the EEG as the animal traverses the place field. This relationship is known as theta precession. A long-standing prediction following the observation of theta precession has been that among a collection of hippocampal neurons recorded simultaneously, the neurons will fire in sequences reflecting the behavioral order of the place fields. Here we examine this prediction. We show that clear, ordered sequences occur during theta, which we name theta sequences, in which a portion of the animal's spatial experience is played out in forwards order. We further investigate the relationship of theta sequences to phase precession by shuffling spike phases in such a way as to preserve the relationship between spike phase and position. This jitter significantly reduces the prevalence of theta sequences while leaving theta phase precession intact, suggesting that the presence of theta phase precession is not trivially predictive of theta sequences. Finally, we discuss the relationship between theta sequences and individual place fields, and the possible functional role of theta sequences in navigational learning. © 2007 Wiley-Liss, Inc. KW - theta AU - Foster, David AU - Wilson, Matthew PY - 2007/// UR - http://dx.doi.org/10.1002/hipo.20345 ER -