Graded persistent activity in entorhinal cortex neurons

  title={Graded persistent activity in entorhinal cortex neurons},
  author={Alexei V. Egorov and Bassam N. Hamam and Erik Frans{\'e}n and Michael E. Hasselmo and Angel A. Alonso},
Working memory represents the ability of the brain to hold externally or internally driven information for relatively short periods of time. Persistent neuronal activity is the elementary process underlying working memory but its cellular basis remains unknown. The most widely accepted hypothesis is that persistent activity is based on synaptic reverberations in recurrent circuits. The entorhinal cortex in the parahippocampal region is crucially involved in the acquisition, consolidation and… 
Excitatory-Inhibitory Interactions as the Basis of Working Memory
It is proposed that working memory performance is driven by interactions of excitatory and inhibitory neurons and modulated by calcium dynamics, and retains novel stimuli using a fixed network of neurons connected with probabilities only depending on the cell type.
Spontaneous persistent activity in entorhinal cortex modulates cortico-hippocampal interaction in vivo
The membrane potential of medial entorhinal cortex layer III (MECIII) neurons, a gateway between neocortex and hippocampus, showed spontaneous, stochastic persistent activity in vivo in mice during Up-Down state oscillations (UDS) and its contribution to cortico-hippocampal interaction is revealed.
Switching between “On” and “Off” states of persistent activity in lateral entorhinal layer III neurons
It is demonstrated that single principal layer III neurons of the lateral entorhinal cortex (EC) generate persistent spiking activity with a novel ability to reliably toggle between spikingActivity and a silent state and that the neuronal ability to switch “On” and “Off” persistent activity may facilitate the concurrent representation of temporally segregated information arriving in the EC and being directed toward the hippocampus.
Muscarinic control of graded persistent activity in lateral amygdala neurons
It is shown that principal neurons from the lateral nucleus of the amygdala (LA) can generate intrinsic graded persistent activity that is similar to EC layer V cells, and activation of these cholinergic afferents is sufficient for the graded increases of stable discharge rates even without an associated up‐regulation of Ca2+.
Induction and modulation of persistent activity in a layer V PFC microcircuit model
It is suggested that modulation of the microcircuit's firing characteristics is achieved primarily through changes in its intrinsic mechanism makeup, supporting the hypothesis of multiple bi-stable units in the PFC.
A Neural Circuit Basis for Spatial Working Memory
It is argued that understanding collective neural dynamics in a recurrent microcircuit provides a key step in bridging the gap between network memory function and its underlying cellular mechanisms, and shed fundamental insights into the neural basis of spatial working memory impairment associated with mental disorders.
Long‐lasting intrinsic persistent firing in rat CA1 pyramidal cells: A possible mechanism for active maintenance of memory
Using in vitro whole‐cell recordings, it is demonstrated that brief stimulation reliably elicits long‐lasting persistent firing that is supported by the calcium‐activated non‐selective cationic current, suggesting that the hippocampal region CA1 is capable of active maintenance of memory.


Muscarinic modulation of the oscillatory and repetitive firing properties of entorhinal cortex layer II neurons.
Investigation of intracellular recording in an in vitro rat brain slice preparation shows the muscarinic modulation of the electroresponsive properties of the two distinct classes of medial EC layer II projection neurons, the stellate cells (SCs) and non-SCs, and indicates an important role for the cholinergic system in tuning the oscillatory dynamics of entorhinal neurons.
Neuromodulation: acetylcholine and memory consolidation
  • M. Hasselmo
  • Biology, Psychology
    Trends in Cognitive Sciences
  • 1999
Cellular basis of working memory
Memory Representation within the Parahippocampal Region
It becomes increasingly clear that the parahippocampal cortex can support recognition memory independent of the distinct memory functions of the hippocampus itself, with evidence that the PHR is critical for maintaining odor memories in animals performing the same task.
Muscarinic Induction of Synchronous Population Activity in the Entorhinal Cortex
It is found that in response to muscarinic activation, pools of EC interneurons discharge synchronously by a mechanism not necessarily involving principal cell activation, and their robust epileptogenic character may be of major importance in temporal lobe epilepsy.
Simulations of the Role of the Muscarinic-Activated Calcium-Sensitive Nonspecific Cation CurrentINCM in Entorhinal Neuronal Activity during Delayed Matching Tasks
A network biophysical simulation of the entorhinal cortex is used to demonstrate how the muscarinic-activated calcium-sensitive nonspecific cation current INCM could provide a cellular mechanism for features of the neuronal activity observed during performance of delayed matching tasks.
Formation of mnemonic neuronal responses to visual paired associates in inferotemporal cortex is impaired by perirhinal and entorhinal lesions.
  • S. Higuchi, Y. Miyashita
  • Biology, Psychology
    Proceedings of the National Academy of Sciences of the United States of America
  • 1996
The ability of inferotemporal neurons to represent association between picture pairs was lost after the lesion of entorhinal and perirhinal cortex, most likely through disruption of backward neural signals to the inferotmporal neurons, while the ability of the neurons to respond to a particular visual stimulus was left intact.
Synaptic reverberation underlying mnemonic persistent activity
The medial temporal lobe memory system
The medial temporal lobe memory system is needed to bind together the distributed storage sites in neocortex that represent a whole memory, but the role of this system is only temporary, as time passes after learning, memory stored in neoc cortex gradually becomes independent of medialporal lobe structures.