Electric stimulation fMRI of the perforant pathway to the rat hippocampus

Canals, Santiago; Beyerlein, Michael; Murayama, Yusuke; Logothetis, Nikos K.

doi:10.1016/j.mri.2008.02.018

Cited by 54 publications

(65 citation statements)

References 29 publications

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“…Of note, in the hippocampus, the axial organization of the cellular elements, with a rather precise alignment of dendritic shafts and somas, minimizes the cancellation of current sources from the LFP generators and facilitates the neurophysiological interpretation of the electrically evoked field potentials, such as synaptic currents reflected in the EPSP and spiking activity in the population spike. Using this preparation, we were able to unequivocally show that the EPSP slope was a precise predictor of BOLD signal amplitude, better than either the population spike or the electrical current used for stimulation [48,49]. This result has recently been confirmed in experiments combining electrophysiological recordings with hippocampal CBF measurements based on Laser-Doppler flowmetry [69].…”

Section: (D) Considerations On the Origin Of Fmri Signalssupporting

confidence: 56%

“…Activations were found in the DG, CA3 and CA1 regions, subiculum, entorhinal cortex and the septum [48]. The BOLD signal amplitude was a good predictor of the underlying electrophysiological responses as measured in combined fMRI -electrophysiology experiments in the DG (see below), very stable under urethane anaesthesia and robust across animals [48,49]. These characteristics conferred a quantitative value to the BOLD signal in long-term experiments as those required to investigate the systems-level consequences of LTP.…”

Section: (A) Cellular and Systems Consolidation Of Memoriesmentioning

confidence: 88%

“…In these acute experiments, urethane-anaesthetized rats are implanted in the perforant pathway (PP) and dentate gyrus (DG) with MRI-compatible stimulating and recording electrodes, respectively. Blood oxygenation-level-dependent (BOLD) imaging allows us to record activity-related signals simultaneously over the entire brain, and in combination with microstimulation [48,50] represents a very powerful tool for the study of highly distributed networks. On the other hand, the simultaneously recorded electrophysiological signals let us unequivocally relate BOLD signals with the underlying neuronal activity [51].…”

Section: (A) Cellular and Systems Consolidation Of Memoriesmentioning

confidence: 99%

“…Using this technique, we showed-perhaps not surprisingly-that electric stimulation of the medial perforant tract produces fMRI maps that spatially correlate with the characteristic pattern of terminal fields of its axons [53][54][55][56]. Activations were found in the DG, CA3 and CA1 regions, subiculum, entorhinal cortex and the septum [48]. The BOLD signal amplitude was a good predictor of the underlying electrophysiological responses as measured in combined fMRI -electrophysiology experiments in the DG (see below), very stable under urethane anaesthesia and robust across animals [48,49].…”

Section: (A) Cellular and Systems Consolidation Of Memoriesmentioning

confidence: 99%

“…and secured in a stereotaxic device. Stimulating electrodes were implanted using standard surgical and stereotaxic procedures, as described previously [48,49]. A twisted platinum-iridium Teflon-coated bipolar electrode (200 mm diameter, 10-15 kW: A-M Systems, WA, USA) was positioned in the medial PP (from l: 0 mm anteroposterior and 4.1-4.5 mm lateral, 2.5-3 mm ventral to the dural surface) for orthodromic stimulation of the DG and the hippocampus proper [95].…”

Section: (A) Electrode Implantation Microestimulation and Recordingmentioning

confidence: 99%

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Functional MRI of long-term potentiation: imaging network plasticity

Álvarez-Salvado

Pallarés

Moreno

et al. 2014

Phil. Trans. R. Soc. B

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Neurons are able to express long-lasting and activity-dependent modulations of their synapses. This plastic property supports memory and conveys an extraordinary adaptive value, because it allows an individual to learn from, and respond to, changes in the environment. Molecular and physiological changes at the cellular level as well as network interactions are required in order to encode a pattern of synaptic activity into a longterm memory. While the cellular mechanisms linking synaptic plasticity to memory have been intensively studied, those regulating network interactions have received less attention. Combining high-resolution fMRI and in vivo electrophysiology in rats, we have previously reported a functional remodelling of long-range hippocampal networks induced by long-term potentiation (LTP) of synaptic plasticity in the perforant pathway. Here, we present new results demonstrating an increased bilateral coupling in the hippocampus specifically supported by the mossy cell commissural/ associational pathway in response to LTP. This fMRI-measured increase in bilateral connectivity is accompanied by potentiation of the corresponding polysynaptically evoked commissural potential in the contralateral dentate gyrus and depression of the inactive convergent commissural pathway to the ipsilateral dentate. We review these and previous findings in the broader context of memory consolidation.

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Section: (D) Considerations On the Origin Of Fmri Signalssupporting

confidence: 56%

Section: (A) Cellular and Systems Consolidation Of Memoriesmentioning

confidence: 88%

Section: (A) Cellular and Systems Consolidation Of Memoriesmentioning

confidence: 99%

Section: (A) Cellular and Systems Consolidation Of Memoriesmentioning

confidence: 99%

Section: (A) Electrode Implantation Microestimulation and Recordingmentioning

confidence: 99%

See 3 more Smart Citations

Functional MRI of long-term potentiation: imaging network plasticity

Álvarez-Salvado

Pallarés

Moreno

et al. 2014

Phil. Trans. R. Soc. B

Self Cite

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Neuromodulation in Small AnimalfMRI

Hsu,

Shih

2024

Magnetic Resonance Imaging

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The integration of functional magnetic resonance imaging (fMRI) with advanced neuroscience technologies in experimental small animal models offers a unique path to interrogate the causal relationships between regional brain activity and brain‐wide network measures—a goal challenging to accomplish in human subjects. This review traces the historical development of the neuromodulation techniques commonly used in rodents, such as electrical deep brain stimulation, optogenetics, and chemogenetics, and focuses on their application with fMRI. We discuss their advantageousness roles in uncovering the signaling architecture within the brain and the methodological considerations necessary when conducting these experiments. By presenting several rodent‐based case studies, we aim to demonstrate the potential of the multimodal neuromodulation approach in shedding light on neurovascular coupling, the neural basis of brain network functions, and their connections to behaviors. Key findings highlight the cell‐type and circuit‐specific modulation of brain‐wide activity patterns and their behavioral correlates. We also discuss several future directions and feature the use of mediation and moderation analytical models beyond the intuitive evoked response mapping, to better leverage the rich information available in fMRI data with neuromodulation. Using fMRI alongside neuromodulation techniques provide insights into the mesoscopic (relating to the intermediate scale between single neurons and large‐scale brain networks) and macroscopic fMRI measures that correlate with specific neuronal events. This integration bridges the gap between different scales of neuroscience research, facilitating the exploration and testing of novel therapeutic strategies aimed at altering network‐mediated behaviors. In conclusion, the combination of fMRI with neuromodulation techniques provides crucial insights into mesoscopic and macroscopic brain dynamics, advancing our understanding of brain function in health and disease.Evidence Level1Technical EfficacyStage 1

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