Topic: hippocampal CA1 neurons

Understanding memory encoding and recall processes in the hippocampus is pivotal for unravelling brain function. We employed two-photon calcium imaging to observe neuronal activity (hippocampal CA1 neurons) in behaving mice performing spatial memory tasks, capturing the dynamics of memory-related circuits. Shannon Information Theory provides a useful toolbox, applicable to the analysis of calcium imaging datasets, to assay changes in information representation and processing in brain circuits while mice are performing such cognitive tasks. In particular, the recently developed Partial Informat

A major component of Alzheimer's disease pathology is the accumulation of amyloid-β (Aβ), a peptide that is known to weaken synaptic transmission. Whereas both AMPA receptor (AMPAR) and NMDA receptor (NMDAR) currents are affected by Aβ oligomers, not all synapses are equally vulnerable to the toxic effects of Aβ. We set out to elucidate the roles of the different AMPAR and NMDAR subunits in synapse susceptibility to Aβ. Whole-cell patch clamp recordings were performed in hippocampal CA1 neurons that overexpress Aβ oligomers. Variance analysis was used to disentangle whether this decreased syna

Cyclic adenosine monophosphate (cAMP) is a ubiquitous second messenger that, when raised by forskolin, induces long-term potentiation (LTP) of synaptic transmission and expression of immediate early genes such as FOS by activating the postsynaptic PKA-CREB pathway. However, most studies have relied on pharmacological tools whose actions are not confined to specific cells or synaptic compartments. Here, we use photoactivatable adenylyl cyclases to raise cAMP in single postsynaptic hippocampal CA1 neurons, in many presynaptic CA3 or postsynaptic CA1 neurons or in all excitatory neurons to invest

The hippocampal representation of space can change on a time scale of minutes as a result of goal learning. However, the link between behaviour performance and the representation of other variables in the hippocampus is less clear, especially at longer time scales. To investigate this, we recorded the activity of hippocampal CA1 neurons of rats using in vivo electrophysiology, as they learned a space-context association task over the course of 5 days. To assess the representation of different task-related variables such as position, reward, movement direction or context in the population activ

Distinct patterns of DNA methylation (mC) and hydroxymethylation (hmC) are identified in the neuronal epigenome, and the dynamic regulation of mC/hmC is associated with various hippocampus-dependent memory processes. hmC, an oxidized form of mC, acts as an essential intermediate in the active DNA demethylation pathway. The further oxidized hmC derivatives are eventually removed by the thymine DNA glycosylase (TDG) initiated base excision repair (BER). Constitutive knockout or catalytic inactivation of TDG leads to embryonic lethality in mice, demonstrating an essential role of TDG in the epige

Theoretical studies show that, operating at criticality maximises both the information processing and storage capabilities of neural systems. Experimental indications that the brain might operate in this way come in the form of: (1) power law distributions of avalanches and (2) non-Gaussian fixed points that appear in phenomenological renormalization group analysis. Despite theoretical benefits and experimental findings, it remains highly debated whether neural criticality is functionally relevant. Firstly, it is hard to confirm if avalanches follow true power laws. Secondly, recent studies in