Selective real-time monitoring of diverse neuronal types in the brain
Cognitive processes emerge from the collective activity of billions of neurons in the brain. The brain is composed of different types of neurons, defined by morphology, connectivity, and genetic expression. In particular, neurons of the mammalian cortex can be sub-divided into two broad classes: excitatory and inhibitory neurons. Alteration in the function of inhibitory cell networks can lead to debilitating neurological disorders that is observed, for example, in epilepsy. Thus, monitoring the electrical potentials (“spikes”) emitted by specific neuronal populations, possibly in real time, will open avenues in the understanding of neuronal networks in vivo and the development of new therapeutic approaches.
This project aims to detect, sort, and classify in real time the spiking activity of different types of neurons in the brain. Findings of this project will provide foundations for the understanding of neuronal dynamics in vivo and the development of closed-loop scientific and therapeutic strategies. Additionally, the project will provide a strong research environment, as well as capacity building and exchange opportunities for graduate students and researchers based in Argentina and Mexico.
The project is led in Canada by McGill University in collaboration with Tel Aviv University in Israel, Universidad Nacional Autonoma de Mexico, and Universidad de Buenos Aires in Argentina.
This project was selected for funding through the fourth research competition of the Joint Canada-Israel Health Research Program. This initiative is a partnership between IDRC, the Canadian Institutes of Health Research, the Israel Science Foundation, and the Azrieli Foundation.
Project ID
108877
Project Status
Completed
End Date
Duration
36 months
IDRC Officer
Fabiano Santos
Total Funding
CA$ 669,900.00
Institution Country
Canada
Project Leader
Adrien Peyrache
Institution
The Royal Institution for the Advancement of Learning/McGill University
Institution Website
Outputs
|
Querying hippocampal replay with subcortical inputs Article
During sleep, the hippocampus recapitulates neuronal patterns corresponding to behavioral trajectories during previous experiences. This hippocampal replay supports the formation of long-term memories. Yet, whether replay originates within the hippocampal circuitry or is initiated by extrahippocampal inputs is unknown. Here, I review recent findings regarding the organization of neuronal activity upstream to the hippocampus, in the head-direction (HD) and grid cell networks, and its relationship to replay. I argue that hippocampal activity at the onset of replay is under the influence of signals from primary spatial areas. In turn, hippocampal replay resets the HD network activity to select a new direction for the next replay event. This reciprocal interaction between the HD network and the hippocampus may be essential in grounding meaning to hippocampal activity, specifically by training decoders of hippocampal sequences. Neuronal dynamics in thalamo-hippocampal loops may thus be instrumental for memory processes during sleep. Author(s): Peyrache, Adrien Language: English |
Reciprocal feature encoding by cortical excitatory and inhibitory neurons Article
In the cortex, the interplay between excitation and inhibition determines the fidelity of neuronal representations. However, while the receptive fields of excitatory neurons are often fine-tuned to the encoded features, the principles governing the tuning of inhibitory neurons are still elusive. We addressed this problem by recording populations of neurons in the postsubiculum (PoSub), a cortical area where the receptive fields of most excitatory neurons correspond to a specific head-direction (HD). In contrast to PoSub-HD cells, the tuning of fast-spiking (FS) cells, the largest class of cortical inhibitory neurons, was broad and heterogeneous. However, we found that PoSub-FS cell tuning curves were often fine-tuned in the spatial frequency domain, which resulted in various radial symmetries in their HD tuning. In addition, the average frequency spectrum of PoSub-FS cell populations was virtually indistinguishable from that of PoSub-HD cells but different from that of the upstream thalamic HD cells, suggesting that this population cotuning in the frequency domain has a local origin. Two observations corroborated this hypothesis. First, PoSub-FS cell tuning was independent of upstream thalamic inputs. Second, PoSub-FS cell tuning was tightly coupled to PoSub-HD cell activity even during sleep. Together, these findings provide evidence that the resolution of neuronal tuning is an intrinsic property of local cortical networks, shared by both excitatory and inhibitory cell populations. We hypothesize that this reciprocal feature encoding supports two parallel streams of information processing in thalamocortical networks. Author(s): Duszkiewicz, Adrian J., Carrasco, Sofia Skromne, Orhan, Pierre, Brown, Eleanor H., Owczarek, Eliott, Vite, Gilberto R., Wood, Emma R., Peyrache, Adrien Language: English |