scholarly journals Instantaneous amplitude and shape of postrhinal theta oscillations differentially encode running speed

2020 ◽  
Author(s):  
Megha Ghosh ◽  
Benjamin E. Shanahan ◽  
Sharon C. Furtak ◽  
George A. Mashour ◽  
Rebecca D. Burwell ◽  
...  
Keyword(s):  
Theta Oscillations ◽  
Instantaneous Amplitude ◽  
Single Cycle ◽  
Running Speed ◽  
Behavioral Correlates ◽  
Temporal Asymmetry ◽  
Rapid Changes ◽  
Postrhinal Cortex ◽  
Cortical Regions ◽  
Hippocampal Theta

ABSTRACTHippocampal theta oscillations have a temporally asymmetric waveform shape, but it is not known if this theta asymmetry extends to all other cortical regions involved in spatial navigation and memory. Here, using both established and improved cycle-by-cycle analysis methods, we show that theta waveforms in the postrhinal cortex are also temporally asymmetric. On average, the falling phase of postrhinal theta cycles lasts longer than the subsequent rising phase. There are, however, rapid changes in both the instantaneous amplitude and instantaneous temporal asymmetry of postrhinal theta cycles. These rapid changes in amplitude and asymmetry are very poorly correlated, indicative of a mechanistic disconnect between these theta cycle features. We show that the instantaneous amplitude and asymmetry of postrhinal theta cycles differentially encode running speed. Although theta amplitude continues to increase at the fastest running speeds, temporal asymmetry of the theta waveform shape plateaus after medium speeds. Our results suggest that the amplitude and waveform shape of individual postrhinal theta cycles may be governed by partially independent mechanisms and emphasize the importance of employing a single cycle approach to understanding the genesis and behavioral correlates of cortical theta rhythms.

scholarly journals Functional dissociation of theta oscillations in the frontal and visual cortices and their long-range network during sustained attention

2019 ◽  
Author(s):  
Hio-Been Han ◽  
Ka Eun Lee ◽  
Jee Hyun Choi
Keyword(s):  
Long Range ◽  
Sustained Attention ◽  
Brain Regions ◽  
Theta Oscillations ◽  
Behavioral Correlates ◽  
Contradictory Behavior ◽  
Visual Cortices ◽  
Cortical Regions ◽  
Phase Amplitude ◽  
Term Performance

ABSTRACTTheta-band (4–12 Hz) activities in the frontal cortex have been thought to be a key mechanism of sustained attention and goal-related behaviors, forming a phase-coherent network with task-related sensory cortices for integrated neuronal ensembles. However, recent visual task studies found that selective attention attenuates stimulus-related theta power in the visual cortex, suggesting a functional dissociation of cortical theta oscillations. To investigate this contradictory behavior of cortical theta, a visual Go/No-Go task was performed with electroencephalogram recording in mice. During the No-Go period, transient theta oscillations were observed in both the frontal and visual cortices, but theta oscillations of the two areas were prominent in different trial epochs. By separating trial epochs based on subjects’ short-term performance, we found that frontal theta was prominent in good-performance epochs, while visual theta was prominent in bad-performance epochs, exhibiting a functional dissociation of cortical theta rhythms. Furthermore, the two theta rhythms also showed a heterogeneous pattern of phase-amplitude coupling with fast oscillations, reflecting their distinct architecture in underlying neuronal circuitry. Interestingly, in good-performance epochs, where visual theta was relatively weak, stronger fronto-visual long-range synchrony and shorter posterior-to-anterior temporal delay were found. These findings highlight a previously overlooked aspect of long-range synchrony between distinct oscillatory entities in the cerebral cortex and provide empirical evidence of a functional dissociation of cortical theta rhythms.IN BRIEFPrevious literature emphasized the pro-cognitive role of coherent oscillatory networks between distal brain regions, such as the fronto-visual theta synchrony. However, such a conceptual framework has been challenged as recent findings revealed distinct behavioral correlates of theta oscillations found in different cortical regions, especially in the frontal and visual cortices. Here, we show that frontal and visual theta represent distinct cortical processes and that the functional connectivity between them increases during sustained attention, especially when one of the two theta rhythms is relatively suppressed. The data presented here highlight a novel aspect of neural long-range synchrony between distinct cortical oscillators with distinct functional significance in task performance.

scholarly journals Direct brain recordings reveal hippocampal rhythm underpinnings of language processing

2016 ◽  
Vol 113 (40) ◽  
pp. 11366-11371 ◽  
Author(s):  
Vitória Piai ◽  
Kristopher L. Anderson ◽  
Jack J. Lin ◽  
Callum Dewar ◽  
Josef Parvizi ◽  
...  
Keyword(s):  
Language Processing ◽  
Sentence Processing ◽  
Memory Function ◽  
Semantic Knowledge ◽  
Theta Oscillations ◽  
Linguistic Processing ◽  
Picture Presentation ◽  
Cortical Regions ◽  
Hippocampal Theta ◽  
Hippocampal Complex

Language is classically thought to be supported by perisylvian cortical regions. Here we provide intracranial evidence linking the hippocampal complex to linguistic processing. We used direct recordings from the hippocampal structures to investigate whether theta oscillations, pivotal in memory function, track the amount of contextual linguistic information provided in sentences. Twelve participants heard sentences that were either constrained (“She locked the door with the”) or unconstrained (“She walked in here with the”) before presentation of the final word (“key”), shown as a picture that participants had to name. Hippocampal theta power increased for constrained relative to unconstrained contexts during sentence processing, preceding picture presentation. Our study implicates hippocampal theta oscillations in a language task using natural language associations that do not require memorization. These findings reveal that the hippocampal complex contributes to language in an active fashion, relating incoming words to stored semantic knowledge, a necessary process in the generation of sentence meaning.

scholarly journals Instantaneous amplitude and shape of postrhinal theta oscillations differentially encode running speed.

2020 ◽  
Vol 134 (6) ◽  
pp. 516-528
Author(s):  
Megha Ghosh ◽  
Benjamin E. Shanahan ◽  
Sharon C. Furtak ◽  
George A. Mashour ◽  
Rebecca D. Burwell ◽  
...  
Keyword(s):  
Theta Oscillations ◽  
Instantaneous Amplitude ◽  
Running Speed

scholarly journals Supramammillary neurons projecting to the septum regulate dopamine and motivation for environmental interaction in mice

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Andrew J. Kesner ◽  
Rick Shin ◽  
Coleman B. Calva ◽  
Reuben F. Don ◽  
Sue Junn ◽  
...  
Keyword(s):  
Ventral Tegmental Area ◽  
Dopamine Neurons ◽  
Theta Oscillations ◽  
Mesolimbic Dopamine ◽  
Sucrose Consumption ◽  
Behavioral Interaction ◽  
Hypothalamic Structure ◽  
Hippocampal Theta ◽  
Substances Of Abuse ◽  
Stimulation Of

AbstractThe supramammillary region (SuM) is a posterior hypothalamic structure, known to regulate hippocampal theta oscillations and arousal. However, recent studies reported that the stimulation of SuM neurons with neuroactive chemicals, including substances of abuse, is reinforcing. We conducted experiments to elucidate how SuM neurons mediate such effects. Using optogenetics, we found that the excitation of SuM glutamatergic (GLU) neurons was reinforcing in mice; this effect was relayed by their projections to septal GLU neurons. SuM neurons were active during exploration and approach behavior and diminished activity during sucrose consumption. Consistently, inhibition of SuM neurons disrupted approach responses, but not sucrose consumption. Such functions are similar to those of mesolimbic dopamine neurons. Indeed, the stimulation of SuM-to-septum GLU neurons and septum-to-ventral tegmental area (VTA) GLU neurons activated mesolimbic dopamine neurons. We propose that the supramammillo-septo-VTA pathway regulates arousal that reinforces and energizes behavioral interaction with the environment.

scholarly journals Conceptualization and validation of an open-source closed-loop deep brain stimulation system in rat

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Hemmings Wu ◽  
Hartwin Ghekiere ◽  
Dorien Beeckmans ◽  
Tim Tambuyzer ◽  
Kris van Kuyck ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Deep Brain Stimulation ◽  
Open Source ◽  
Brain Stimulation ◽  
Closed Loop ◽  
Symptom Control ◽  
Theta Oscillations ◽  
Open Source Hardware ◽  
Hippocampal Theta ◽  
Deep Brain

Abstract Conventional deep brain stimulation (DBS) applies constant electrical stimulation to specific brain regions to treat neurological disorders. Closed-loop DBS with real-time feedback is gaining attention in recent years, after proved more effective than conventional DBS in terms of pathological symptom control clinically. Here we demonstrate the conceptualization and validation of a closed-loop DBS system using open-source hardware. We used hippocampal theta oscillations as system input and electrical stimulation in the mesencephalic reticular formation (mRt) as controller output. It is well documented that hippocampal theta oscillations are highly related to locomotion, while electrical stimulation in the mRt induces freezing. We used an Arduino open-source microcontroller between input and output sources. This allowed us to use hippocampal local field potentials (LFPs) to steer electrical stimulation in the mRt. Our results showed that closed-loop DBS significantly suppressed locomotion compared to no stimulation and required on average only 56% of the stimulation used in open-loop DBS to reach similar effects. The main advantages of open-source hardware include wide selection and availability, high customizability and affordability. Our open-source closed-loop DBS system is effective and warrants further research using open-source hardware for closed-loop neuromodulation.

scholarly journals Flexible theta sequence compression mediated via phase precessing interneurons

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Angus Chadwick ◽  
Mark CW van Rossum ◽  
Matthew F Nolan
Keyword(s):  
Action Potentials ◽  
High Capacity ◽  
Theta Oscillations ◽  
Sequence Generation ◽  
Spike Sequences ◽  
Theta Frequency ◽  
Neural Substrate ◽  
Hippocampal Theta ◽  
Novel Model ◽  
Sequence Compression

Encoding of behavioral episodes as spike sequences during hippocampal theta oscillations provides a neural substrate for computations on events extended across time and space. However, the mechanisms underlying the numerous and diverse experimentally observed properties of theta sequences remain poorly understood. Here we account for theta sequences using a novel model constrained by the septo-hippocampal circuitry. We show that when spontaneously active interneurons integrate spatial signals and theta frequency pacemaker inputs, they generate phase precessing action potentials that can coordinate theta sequences in place cell populations. We reveal novel constraints on sequence generation, predict cellular properties and neural dynamics that characterize sequence compression, identify circuit organization principles for high capacity sequential representation, and show that theta sequences can be used as substrates for association of conditioned stimuli with recent and upcoming events. Our results suggest mechanisms for flexible sequence compression that are suited to associative learning across an animal’s lifespan.

scholarly journals Optogenetic activation of SST-positive interneurons restores hippocampal theta oscillation impairment induced by soluble amyloid beta oligomersin vivo

2018 ◽  
Author(s):  
Hyowon Chung ◽  
Kyerl Park ◽  
Hyun Jae Jang ◽  
Michael M Kohl ◽  
Jeehyun Kwag
Keyword(s):  
Learning And Memory ◽  
Peak Power ◽  
Pyramidal Neurons ◽  
Hippocampal Slices ◽  
Field Potential ◽  
Theta Oscillations ◽  
Ca1 Pyramidal Neurons ◽  
Theta Frequency ◽  
Hippocampal Theta

AbstractAbnormal accumulation of amyloid β oligomers (AβO) is a hallmark of Alzheimer’s disease (AD), which leads to learning and memory deficits. Hippocampal theta oscillations that are critical in spatial navigation, learning and memory are impaired in AD. Since GABAergic interneurons, such as somatostatin-positive (SST+) and parvalbumin-positive (PV+) interneurons, are believed to play key roles in the hippocampal oscillogenesis, we asked whether AβO selectively impairs these SST+ and PV+ interneurons. To selectively manipulate SST+ or PV+ interneuron activity in mice with AβO pathologyin vivo, we co-injected AβO and adeno-associated virus (AAV) for expressing floxed channelrhodopsin-2 (ChR2) into the hippocampus of SST-Cre or PV-Cre mice. Local field potential (LFP) recordingsin vivoin these AβO–injected mice showed a reduction in the peak power of theta oscillations and desynchronization of spikes from CA1 pyramidal neurons relative to theta oscillations compared to those in control mice. Optogenetic-activation of SST+ but not PV+ interneurons in AβO–injected mice fully restored the peak power of theta oscillations and resynchronized the theta spike phases to a level observed in control mice.In vitrowhole-cell voltage-clamp recordings in CA1 pyramidal neurons in hippocampal slices treated with AβO revealed that short-term plasticity of SST+ interneuron inhibitory inputs to CA1 pyramidal neurons at theta frequency were selectively disrupted while that of PV+ interneuron inputs were unaffected. Together, our results suggest that dysfunction in inputs from SST+ interneurons to CA1 pyramidal neurons may underlie the impairment of theta oscillations observed in AβO-injected micein vivo.Our findings identify SST+ interneurons as a target for restoring theta-frequency oscillations in early AD.

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