Faculty Opinions recommendation of Place-selective firing of CA1 pyramidal cells during sharp wave/ripple network patterns in exploratory behavior.

2006 ◽  
Author(s):  
Edvard I Moser
Keyword(s):  
Exploratory Behavior ◽  
Pyramidal Cells ◽  
Ca1 Pyramidal Cells ◽  
Sharp Wave ◽  
Network Patterns

scholarly journals Most hippocampal CA1 pyramidal cells in rabbits increase firing during awake sharp-wave ripples and some do so in response to external stimulation and theta

2020 ◽  
Vol 123 (5) ◽  
pp. 1671-1681
Author(s):  
Miriam S. Nokia ◽  
Tomi Waselius ◽  
Joonas Sahramäki ◽  
Markku Penttonen
Keyword(s):  
Eyeblink Conditioning ◽  
Cell Activity ◽  
Pyramidal Cells ◽  
External Stimulation ◽  
Ca1 Pyramidal Cells ◽  
Sharp Wave ◽  
Hippocampal Ca1 ◽  
Trace Eyeblink Conditioning ◽  
Do So

We studied hippocampal sharp-wave ripples and theta and CA1 pyramidal cell activity during trace eyeblink conditioning in rabbits. Conditioning trials suppressed ripples while increasing theta for a period of several seconds. A quarter of the cells increased firing in response to the conditioned stimulus and fired extensively during endogenous theta as well as ripples. The role of endogenous theta epochs in off-line memory consolidation should be studied further.

scholarly journals NMDA receptors promote hippocampal sharp‐wave ripples and the associated coactivity of CA1 pyramidal cells

Hippocampus ◽  
2020 ◽  
Vol 30 (12) ◽  
pp. 1356-1370
Author(s):  
Timothy Howe ◽  
Anthony J. Blockeel ◽  
Hannah Taylor ◽  
Matthew W. Jones ◽  
Maxim Bazhenov ◽  
...  
Keyword(s):  
Nmda Receptors ◽  
Pyramidal Cells ◽  
Ca1 Pyramidal Cells ◽  
Sharp Wave

scholarly journals Prenatal alcohol exposure disrupts hippocampal sharp‐wave ripple‐associated spike dynamics

2021 ◽  
Author(s):  
Ryan E Harvey ◽  
Laura E Berkowitz ◽  
Daniel D Savage ◽  
Benjamin J Clark
Keyword(s):  
Prenatal Alcohol Exposure ◽  
Pyramidal Cells ◽  
Population Level ◽  
Alcohol Exposure ◽  
Intrinsic Structure ◽  
Ca1 Pyramidal Cells ◽  
Sharp Wave ◽  
Activation Rate ◽  
Prenatal Alcohol ◽  
Spike Dynamics

Prenatal alcohol exposure (PAE) is among the most common developmental insults to the nervous system and is characterized by memory disruption. There is a pressing need to identify physiological alterations that help explain this memory impairment. Hippocampal sharp-wave ripples (SPW-Rs) are a compelling candidate for this purpose as they are the electrophysiological signatures of memory consolidation. We report that rats exposed to moderate prenatal alcohol display abnormalities restricted to SPW-R episodes that manifest as decreased recruitment of CA1 pyramidal cells and interneurons to SPW-R events, altered excitation during SPW-Rs, and decreased cell assembly activation rate. These differences observed at the single neuron and the population level may limit the ability of memory trace reactivation during SPW-Rs through the disruption of the intrinsic structure of cell sequences. Together, our results suggest that alterations in hippocampal SPW-R spike dynamics may underlie alcohol exposure-related memory deficits.

scholarly journals Disruption of perineuronal nets increases the frequency of sharp wave ripples

2017 ◽  
Author(s):  
ZhiYong Sun ◽  
P. Lorenzo Bozzelli ◽  
Adam Caccavano ◽  
Megan Allen ◽  
Jason Balmuth ◽  
...  
Keyword(s):  
Slow Wave Sleep ◽  
Neuronal Cell ◽  
Pyramidal Cells ◽  
Neuronal Population ◽  
Stratum Radiatum ◽  
Perineuronal Nets ◽  
Ca1 Pyramidal Cells ◽  
Sharp Wave ◽  
Initial Excitation ◽  
Ca3 Pyramidal Cells

AbstractHippocampal sharp wave ripples (SWRs) represent irregularly occurring synchronous neuronal population events that are observed during phases of rest and slow wave sleep. SWR activity that follows learning involves sequential replay of training-associated neuronal assemblies and is critical for systems level memory consolidation. SWRs are initiated by CA2 or CA3 pyramidal cells and require initial excitation of CA1 pyramidal cells as well as subsequent participation of parvalbumin (PV) expressing fast spiking (FS) inhibitory interneurons. These interneurons are relatively unique in that they represent the major neuronal cell type known to be surrounded by perineuronal nets (PNNs), lattice like structures composed of a hyaluronin backbone that surround the cell soma and proximal dendrites. Though the function of the PNN is not completely understood, previous studies suggest it may serve to localize glutamatergic input to synaptic contacts and thus influence the activity of ensheathed cells. Noting that FS PV interneurons impact the activity of pyramidal cells thought to initiate SWRs, and that their activity is critical to ripple expression, we examine the effects of PNN integrity on SWR activity in the hippocampus. Extracellular recordings from the stratum radiatum of 490 micron horizontal murine hippocampal hemisections demonstrate SWRs that occur spontaneously in CA1. As compared to vehicle, pretreatment (120 min) of paired hemislices with hyaluronidase, which cleaves the hyaluronin backbone of the PNN, decreases PNN integrity and increases SWR frequency. Pretreatment with chondroitinase, which cleaves PNN side chains, also increases SWR frequency. Together, these data contribute to an emerging appreciation of extracellular matrix as a regulator of neuronal plasticity and suggest that one function of mature perineuronal nets could be to modulate the frequency of SWR events.

scholarly journals The Entorhinal Cortical Alvear Pathway Differentially Excites Pyramidal Cells and Interneuron Subtypes in Hippocampal CA1

2020 ◽  
Author(s):  
Karen A Bell ◽  
Rayne Delong ◽  
Priyodarshan Goswamee ◽  
A Rory McQuiston
Keyword(s):  
Brain Slices ◽  
Pyramidal Cells ◽  
Excitatory Input ◽  
Theta Burst Stimulation ◽  
Ca1 Pyramidal Cells ◽  
Whole Cell Patch Clamp ◽  
Hippocampal Ca1 ◽  
Physiological Impact ◽  
Theta Burst ◽  
Synaptic Responses

Abstract The entorhinal cortex alvear pathway is a major excitatory input to hippocampal CA1, yet nothing is known about its physiological impact. We investigated the alvear pathway projection and innervation of neurons in CA1 using optogenetics and whole cell patch clamp methods in transgenic mouse brain slices. Using this approach, we show that the medial entorhinal cortical alvear inputs onto CA1 pyramidal cells (PCs) and interneurons with cell bodies located in stratum oriens were monosynaptic, had low release probability, and were mediated by glutamate receptors. Optogenetic theta burst stimulation was unable to elicit suprathreshold activation of CA1 PCs but was capable of activating CA1 interneurons. However, different subtypes of interneurons were not equally affected. Higher burst action potential frequencies were observed in parvalbumin-expressing interneurons relative to vasoactive-intestinal peptide-expressing or a subset of oriens lacunosum-moleculare (O-LM) interneurons. Furthermore, alvear excitatory synaptic responses were observed in greater than 70% of PV and VIP interneurons and less than 20% of O-LM cells. Finally, greater than 50% of theta burst-driven inhibitory postsynaptic current amplitudes in CA1 PCs were inhibited by optogenetic suppression of PV interneurons. Therefore, our data suggest that the alvear pathway primarily affects hippocampal CA1 function through feedforward inhibition of select interneuron subtypes.

Level of Arousal During the Small Irregular Activity State in the Rat Hippocampal EEG

2004 ◽  
Vol 91 (6) ◽  
pp. 2649-2657 ◽  
Author(s):  
Beata Jarosiewicz ◽  
William E. Skaggs
Keyword(s):  
Slow Wave Sleep ◽  
Power Spectra ◽  
Pyramidal Cells ◽  
Auditory Stimuli ◽  
Sleep State ◽  
Population Activity ◽  
Ca1 Pyramidal Cells ◽  
Emg Amplitude ◽  
Current Location ◽  
Activity State

The sleeping rat cycles between two well-characterized hippocampal physiological states, large irregular activity (LIA) during slow-wave sleep (SWS) and theta activity during rapid-eye-movement sleep (REM). A third, less well-characterized electroencephalographic (EEG) state, termed “small irregular activity” (SIA), has been reported to occur when an animal is startled out of sleep without moving and during active waking when it abruptly freezes. We recently found that the hippocampal population activity of a spontaneous sleep state whose EEG resembles SIA reflects the rat's current location in space, suggesting that it is also a state of heightened arousal. To test whether this spontaneous SIA state corresponds to the SIA state reported in the literature and to compare the level of arousal during SIA to the other well-characterized physiological states, we recorded unit activity from ensembles of hippocampal CA1 pyramidal cells, EEG from the hippocampus and the neocortex, and electromyography (EMG) from the dorsal neck musculature in rats presented with auditory stimuli while foraging for randomly scattered food pellets and while sleeping. Auditory stimuli presented during sleep reliably induced SIA episodes very similar to spontaneous SIA in hippocampal and neocortical EEG amplitudes and power spectra, EMG amplitude, and CA1 population activity. Both spontaneous and elicited SIA exhibited neocortical desynchronization, and both had EMG amplitude comparable to that of waking LIA. We conclude based on this and other evidence that spontaneous SIA and elicited SIA correspond to a single state and that the level of arousal in SIA is higher than in the well-characterized sleep states but lower than the active theta state.

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