Ivan Fernandez-Lamo's research while affiliated with Cajal Institute and other places

Publications (10)

Article
Full-text available
Hippocampal sclerosis, the major neuropathological hallmark of temporal lobe epilepsy, is characterized by different patterns of neuronal loss. The mechanisms of cell-type-specific vulnerability and their progression and histopathological classification remain controversial. Using single-cell electrophysiology in vivo and immediate-early gene expre...
Article
Full-text available
Understanding brain operation demands linking basic behavioral traits to cell-type specific dynamics of different brain-wide subcircuits. This requires a system to classify the basic operational modes of neurons and circuits. Single-cell phenotyping of firing behavior during ongoing oscillations in vivo has provided a large body of evidence on ento...
Preprint
Full-text available
Hippocampal sclerosis, the major neuropathological hallmark of temporal lobe epilepsy, is characterized by different patterns of neuronal loss. The mechanisms of cell-type specific vulnerability, their progression and histopathological classification remain controversial. Here using single-cell electrophysiology in vivo and immediate early gene exp...
Article
Full-text available
The proximodistal axis is considered a major organizational principle of the hippocampus. At the interface between the hippocampus and other brain structures, CA2 apparently breaks this rule. The region is involved in social, temporal, and contextual memory function, but mechanisms remain elusive. Here, we reveal cell-type heterogeneity and a chara...
Preprint
Full-text available
The proximodistal axis is considered a major organizational principle of the hippocampus. Interfacing between the hippocampus and other brain systems, the CA2 region apparently breaks this rule. Apart from its specific role in social memory, CA2 has been involved in temporal and contextual memory but mechanisms remain elusive. Here, we used intrace...
Article
Memory traces are reactivated selectively during sharp-wave ripples. The mechanisms of selective reactivation, and how degraded reactivation affects memory, are poorly understood. We evaluated hippocampal single-cell activity during physiological and pathological sharp-wave ripples using juxtacellular and intracellular recordings in normal and epil...
Article
Full-text available
Recent reports in human demonstrate a role of theta–gamma coupling in memory for spatial episodes and a lack of coupling in people experiencing temporal lobe epilepsy, but the mechanisms are unknown. Using multisite silicon probe recordings of epileptic rats engaged in episodic-like object recognition tasks, we sought to evaluate the role of theta–...

Citations

... Recent advances in single cell nuclear transcriptomics from mouse and human brain have revealed cellular heterogeneity in healthy, aging and disease states (LoVerso and Cui, 2016;Mathys et al., 2019;Lau et al., 2020;Cid et al., 2021), but protein-level inferences cannot be drawn confidently from mRNA levels. Since intact cells cannot be isolated from frozen or fixed human brain, cellular proteomic insights into human ND from human postmortem tissues are very limited. ...
... This is noteworthy because granule cells fire seldom overall and are the cells that supposedly form the initial hippocampal engram (Kitamura et al., 2017) supporting reliable, orthogonal encoding of unique but similar experiences (Rolls, 2018). At the same time, dentate spikes seem to have a feed-forward inhibitory effect on CA3 (Bragin et al., 1995;Sanchez-Aguilera et al., 2021) and CA1 (Penttonen et al., 1997) pyramidal cells as they hyperpolarize and decrease firing concomitant with dentate spikes. That is, whereas SPW-Rs reflect increased firing of neurons projecting from the hippocampus to the neocortex, dentate spikes have an opposite effect resulting in a pause in hippocampal output. ...
... This characteristic is shared with PCs in area CA2, which also are athorny. Interestingly, several studies have also found that the expression of PCP4, a main hallmark of PCs in area CA2, can be detected in PCs in the deep layers of CA3a and the distal part of CA3b (Fernandez-Lamo et al., 2019;San Antonio et al., 2014). Since the functional characterization of PCs in this study was performed in these areas, is it possible that B PC may be CA2-PCs distributed along CA3 deep layers. ...
... As the majority of SWRs recruit high-frequency activity in all CA regions nearly simultaneously (Buzsaki, 2015;Oliva et al., 2016a;Stark et al., 2014;Sullivan et al., 2011), we next computed wavelet spectrograms of LFP recorded in each region, centered at the peak rippleband power (100-250 Hz) of events recorded in CA1. Consistent with prior evidence (Fernandez-Lamo et al., 2019;Oliva et al., 2016a), in control mice ripple power in CA1 was strongly aligned to the SWR peak (Fig. 1f). However, ripple power decreased following CNO in the DREADD mice in CA1 (Fig. 1f), as well as in CA2 and CA3 (Extended Data Fig. 2b). ...
... Animal studies suggest that ripples are related to physiological functions, such as the formation of memory and cognition, while FRs are related to the seizure onset zone (Nevalainen et al., 2020). FRs are able to influence the specific synaptic driving function of CA1 pyramidal cells, make neuronal firing randomized, and ultimately lead to the loss of control of selective discharges in the hippocampus (Valero et al., 2017). It has been suggested that an energy analysis of FRs may be a more sensitive and specific biomarker of epilepsy, compared to ripples. ...
... Afterwards, we repeated our calculations, but as a parameter of theta-gamma coupling, we took the modulation index averaged over the entire time of all behavioral tests for the slow and fast gamma rhythm, as was done by Lopez-Pigozzi et al. (2016). The modulation index measured in this way showed a significant positive correlation with behavioral performance in control group (Fig. 6). ...