Coherence of compound field potentials reveals discontinuities in the CA1-subiculum of the hippocampus in freely-moving rats

Bullock, T. H.; Buzsáki, György; McClune, Michael C.

doi:10.1016/0306-4522(90)90055-9

Cited by 76 publications

(53 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…2). This pattern of theta coherence has also been reported in the freely moving rat in vivo (30,31). Generally, slower oscillations in vivo are spatially more extended (32).…”

Section: Discussionsupporting

confidence: 78%

“…In the intact hippocampal formation, gamma activity is nested within the theta rhythm and is larger during theta-associated behaviors than during immobility (30,34). Thus, we took advantage of the selective orientation possible with hippocampal slices to investigate the interplay between these two rhythms with orientations intermediate between the transverse and horizontal axis.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Orthogonal arrangement of rhythm-generating microcircuits in the hippocampus

Gloveli

Dugladze

Rotstein

et al. 2005

Proc. Natl. Acad. Sci. U.S.A.

221

212

View full text Add to dashboard Cite

As a structure involved in learning and memory, the hippocampus functions as a network. The functional differentiation along the longitudinal axis of the hippocampus is poorly demarcated in comparison with the transverse axis. Using patch clamp recordings in conjunction with post hoc anatomy, we have examined the pattern of connectivity and the functional differentiation along the long axis of the hippocampus. Here, we provide anatomical and physiological evidence that the prominent rhythmic network activities of the hippocampus, the behavior-specific gamma and theta oscillations, are seen predominantly along the transverse and longitudinal axes respectively. This orthogonal relationship is the result of the axonal field trajectories and the consequential interaction of the principal cells and major interneuron subtypes involved in generating each rhythm. Thus, the axonal arborization patterns of hippocampal inhibitory cells may represent a structural framework for the spatiotemporal distribution of activity observed within the hippocampus.interneurons ͉ oscillations ͉ patch clamp T he hippocampus is required for the encoding of new information and for retrieving information shortly after acquisition (1). Spatial information is coded at theta frequencies (2) by clusters of neurons segmentally distributed along the longitudinal axis of the hippocampus (3). Gamma oscillations are also generated by the hippocampus nested within these theta rhythms and are thought to be involved in transient neuronal assembly formation (4), information transmission, and storage (5).As previous observation has shown, the hippocampus is made up of multiple lamellae organized in parallel across the long axis, in which each lamella contains a functionally independent transverse circuit (6). The well defined connections between subregions along the transverse axis facilitates the investigation of crucial neurobiological processes such as network oscillatory activity in the in vitro preparation. Although the functionally segregated subregions of the long axis of the hippocampal formation may cooperate with each other during memory formation (for review, see ref. 7), morphological evidence about their interconnectivity is sparse. Although CA3 neurons connect to other CA3 neurons (8, 9), and excitation of interneurons occurs along the longitudinal axis (10), the involvement of hippocampal interneurons in the functional circuit along the longitudinal axis of hippocampus is still unclear.Interneurons serve a wide variety of functions in the brain, amongst them generating and maintaining local or large scale coherent activity (for review, see ref. 11). They also have a particularly pivotal role in driving inhibition-based rhythms, such as gamma and theta frequency network oscillations (12-16). Theta rhythms are seen as a major operational mode of the hippocampus (for review, see ref. 17), and clusters of neurons that encode information required to perform spatial and nonspatial short-term memory tasks during theta rhythms are distributed in di...

show abstract

“…2). This pattern of theta coherence has also been reported in the freely moving rat in vivo (30,31). Generally, slower oscillations in vivo are spatially more extended (32).…”

Section: Discussionsupporting

confidence: 78%

Section: Discussionmentioning

confidence: 99%

Orthogonal arrangement of rhythm-generating microcircuits in the hippocampus

Gloveli

Dugladze

Rotstein

et al. 2005

Proc. Natl. Acad. Sci. U.S.A.

221

212

View full text Add to dashboard Cite

show abstract

“…Each class of interneuron has its own preferred phase of discharge (Klausberger et al, 2003;Klausberger et al, 2004). In addition to the hippocampus and entorhinal cortex, thetamodulated neurons have been identified in all limbic structures, including the perirhinal cortex (Muir and Bilkey, 1998), cingulate cortex (Leung and Borst, 1987;Colom et al, 1988), prefrontal cortex (Siapas et al, 2005), amygdala (Pare and Gaudreau, 1996;Collins et al, 1999;Pare and Collins, 2000), anterior thalamus (Vertes et al, 2001), mammillary bodies and the supramammillary nucleus (Kocsis and Vertes, 1994), and the subiculum (Bullock et al, 1990;Anderson and O'Mara, 2003). Some of these networks also generate their own theta fields.…”

Section: Slow (<1 Hz) Rhythms-mirceamentioning

confidence: 99%

Interaction between neocortical and hippocampal networks via slow oscillations

Sirota

Buzsáki

2005

THL

231

219

View full text Add to dashboard Cite

Both the thalamocortical and limbic systems generate a variety of brain state-dependent rhythms but the relationship between the oscillatory families is not well understood. Transfer of information across structures can be controlled by the offset oscillations. We suggest that slow oscillation of the neocortex, which was discovered by Mircea Steriade, temporally coordinates the self-organized oscillations in the neocortex, entorhinal cortex, subiculum and hippocampus. Transient coupling between rhythms can guide bidirectional information transfer among these structures and might serve to consolidate memory traces.

show abstract

“…It is well known that the amplitude and phase of theta oscillations depend on the depth, or more precisely the lamina, of the observed signal [25][26][27] , because several current dipoles located in different layers contribute to the macroscopic oscillation 12,[28][29][30][31][32] . Conversely, it is believed that theta oscillations are robustly synchronized within each layer across the anatomical extent of the hippocampus 28,[32][33][34] , despite some early evidence to the contrary 26 . The dominant view is therefore that theta oscillations are a global clock, and the anatomical extent of the hippocampus is synchronized with zero delay or, figuratively speaking, contained in a single time zone 32 .…”

mentioning

confidence: 99%

Hippocampal theta oscillations are travelling waves

Lubenov

Siapas

2009

Nature

442

422

View full text Add to dashboard Cite

Theta oscillations clock hippocampal activity during awake behaviour and rapid eye movement (REM) sleep. These oscillations are prominent in the local field potential, and they also reflect the subthreshold membrane potential and strongly modulate the spiking of hippocampal neurons. The prevailing view is that theta oscillations are synchronized throughout the hippocampus, despite the lack of conclusive experimental evidence. In contrast, here we show that in freely behaving rats, theta oscillations in area CA1 are travelling waves that propagate roughly along the septotemporal axis of the hippocampus. Furthermore, we find that spiking in the CA1 pyramidal cell layer is modulated in a consistent travelling wave pattern. Our results demonstrate that theta oscillations pattern hippocampal activity not only in time, but also across anatomical space. The presence of travelling waves indicates that the instantaneous output of the hippocampus is topographically organized and represents a segment, rather than a point, of physical space.Theta oscillations are a prominent 4-10-Hz rhythm in the hippocampal local field potential (LFP) of all mammals studied to date 1-3 , including humans 4 . During wakefulness they are associated with different speciesspecific behaviours, and they are invariably present during REM sleep 2,3 . In the rat, theta oscillations always accompany voluntary movement and active exploration 2,5 . Theta oscillations are essential for the normal functioning of the hippocampus, because manipulations that disrupt them produce behavioural impairments that mimic hippocampal lesions 6,7 . The importance of theta oscillations is underscored by the fact that they reflect subthreshold membrane potentials [8][9][10] and strongly modulate the spiking 5,11,12,13 of hippocampal neurons. Furthermore, theta oscillations gate synaptic plasticity, because the timing of stimulation with respect to the phase of theta is important in determining the magnitude and direction of synaptic change 14,15 . Theta oscillations therefore offer macroscopic access to the internal clock of the hippocampal circuit, responsible for temporally patterning its operation. Such clocking is essential for the temporal coding of spatial information by place cells 5,16 , as evidenced by theta phase precession [17][18][19] . In addition to coding position, theta phase precession ensures that the order of place-cell firing over behavioural timescales (seconds) is preserved and compressed within individual theta cycles and inside the window of plasticity 18 . In the presence of spike-timing-dependent plasticity 20 , the resulting compression of temporal sequences offers a mechanism for the formation of hippocampal memory traces 21 . Furthermore, theta oscillations modulate activity not only in the hippocampus, but also in several subcortical, limbic and cortical structures [22][23][24] .If theta oscillations can be thought of as a clock, what time is it in different parts of the hippocampus? In other words, how does the phase of theta oscillation...

show abstract

Coherence of compound field potentials reveals discontinuities in the CA1-subiculum of the hippocampus in freely-moving rats

Cited by 76 publications

References 20 publications

Orthogonal arrangement of rhythm-generating microcircuits in the hippocampus

Orthogonal arrangement of rhythm-generating microcircuits in the hippocampus

Interaction between neocortical and hippocampal networks via slow oscillations

Hippocampal theta oscillations are travelling waves

Contact Info

Product

Resources

About