@article {46924, title = {Oscillatory patterns in hippocampus under light and deep isoflurane anesthesia closely mirror prominent brain states in awake animals.}, journal = {Hippocampus}, volume = {26}, year = {2015}, month = {2015 Jul 18}, pages = {102-9}, abstract = {

The hippocampus exhibits a variety of distinct states of activity under different conditions. For instance the rhythmic patterns of activity orchestrated by the theta oscillation during running and REM sleep are markedly different from the large irregular activity (LIA) observed during awake resting and slow wave sleep. We found that under different levels of isoflurane anesthesia activity in the hippocampus of rats displays two distinct states which have several qualities that mirror the theta and LIA states. These data provide further evidence that the two states are intrinsic modes of the hippocampus; while also characterizing a preparation that could be useful for studying the natural activity states in hippocampus. This article is protected by copyright. All rights reserved.

}, issn = {1098-1063}, doi = {10.1002/hipo.22494}, author = {Lustig, Brian and Wang, Yingxue and Pastalkova, Eva} } @article {45792, title = {Theta sequences are essential for internally generated hippocampal firing fields.}, journal = {Nature Neuroscience}, volume = {18}, year = {2015}, month = {2015 Feb}, pages = {282-8}, abstract = {

Sensory cue inputs and memory-related internal brain activities govern the firing of hippocampal neurons, but which specific firing patterns are induced by either of the two processes remains unclear. We found that sensory cues guided the firing of neurons in rats on a timescale of seconds and supported the formation of spatial firing fields. Independently of the sensory inputs, the memory-related network activity coordinated the firing of neurons not only on a second-long timescale, but also on a millisecond-long timescale, and was dependent on medial septum inputs. We propose a network mechanism that might coordinate this internally generated firing. Overall, we suggest that two independent mechanisms support the formation of spatial firing fields in hippocampus, but only the internally organized system supports short-timescale sequential firing and episodic memory.

}, issn = {1546-1726}, doi = {10.1038/nn.3904}, author = {Wang, Yingxue and Romani, Sandro and Lustig, Brian and Leonardo, Anthony and Pastalkova, Eva} } @article {48277, title = {Unilateral whisker trimming in newborn rats alters neuronal coincident discharge among mature barrel cortex neurons.}, journal = {Journal of neurophysiology}, volume = {112}, year = {2014}, month = {2014 Oct 15}, pages = {1925-35}, abstract = {

It is known that sensory deprivation, including postnatal whisker trimming, can lead to severe deficits in the firing rate properties of cortical neurons. Recent results indicate that development of synchronous discharge among cortical neurons is also activity influenced, and that correlated discharge is significantly impaired following loss of bilateral sensory input in rats. Here we investigate whether unilateral whisker trimming (unilateral deprivation or UD) after birth interferes in the same way with the development of synchronous discharge in cortex. We measured the coincidence of spikes among pairs of neurons recorded under urethane anesthesia in one whisker barrel field deprived by trimming all contralateral whiskers for 60 days after birth (UD), and in untrimmed controls (CON). In the septal columns around barrels, UD significantly increased the coincident discharge among cortical neurons compared with CON, most notably in layers II/III. In contrast, synchronous discharge was normal between layer IV UD barrel neurons: i.e., not different from CON. Thus, while bilateral whisker deprivation (BD) produced a global deficit in the development of synchrony in layer IV, UD did not block the development of synchrony between neurons in layer IV barrels and increased synchrony within septal circuits. We conclude that changes in synchronous discharge after UD are unexpectedly different from those recorded after BD, and we speculate that this effect may be due to the driven activity from active commissural inputs arising from the contralateral hemisphere that received normal activity levels during postnatal development.

}, keywords = {Animals, Animals, Newborn, Female, Male, Neurons, Physical Stimulation, Rats, Rats, Long-Evans, Sensory Deprivation, Somatosensory Cortex, Touch, Touch Perception, Vibrissae}, issn = {1522-1598}, doi = {10.1152/jn.00562.2013}, author = {Ghoshal, Ayan and Lustig, Brian and Popescu, Maria and Ebner, Ford and Pouget, Pierre} }