scholarly journals Reciprocal Homosynaptic and Heterosynaptic Long-Term Plasticity of Corticogeniculate Projection Neurons in Layer VI of the Mouse Visual Cortex

2013 ◽  
Vol 33 (18) ◽  
pp. 7787-7798 ◽  
Author(s):  
M. K. Arami ◽  
K. Sohya ◽  
A. Sarihi ◽  
B. Jiang ◽  
Y. Yanagawa ◽  
...  
2020 ◽  
Author(s):  
Shumsuzzaman Khan

AbstractIn reward-based learning, synaptic eligibility traces are a well-defined theoretical solution for the conversion of initial co-activation of pre and postsynaptic neurons into long-term changes in synaptic strength by reward-linked neuromodulators. However, the types of neuromodulators involved in such a phenomenon in mouse visual cortex remain unknown. To characterize the Ex vivo condition, we used optogenetic stimulation of channelrhodopsin-(ChR2) expressing Cre/Ai32(ChR2-eYFP); Tph2-Cre/Ai32(ChR2-eYFP); Thi-Cre/Ai32(ChR2-eYFP) homozygous mice, which release acetylcholine, serotonin, and norepinephrine, respectively. With these mice it is possible to measure the transformation of eligibility traces into long-term changes by endogenous neuromodulators. Here we delineated that layer 2/3 neurons in the visual cortex showed no LTD after conditioning with paired-pulse low-frequency stimulation (ppLFS; 2Hz, 15 min). However, if conditioning was paired with acetylcholine, serotonin, or norepinephrine release upon 473 nm optical stimulation in brain slices, LTD occurs in every case. Thus, our data suggests a new pathway to connect the gap between stimulus and reward. Moreover, we found that stimulation by theta-glass or metal stimulators evoked IPSC traces with the same amplitudes but differences in decay kinetics, further questioning the appropriate use of stimulators in brain slices for evoking an event.


2018 ◽  
Vol 223 (5) ◽  
pp. 2073-2095 ◽  
Author(s):  
Isabelle Scheyltjens ◽  
Samme Vreysen ◽  
Chris Van den Haute ◽  
Victor Sabanov ◽  
Detlef Balschun ◽  
...  

2021 ◽  
Author(s):  
Shumsuzzaman Khan

Abstract In reward-based learning, synaptic eligibility traces are a well-defined theoretical solution for the conversion of initial co-activation of pre and postsynaptic neurons into long-term changes in synaptic strength by reward-linked neuromodulators. However, the types of neuromodulators involved in such a phenomenon in mouse visual cortex remain unknown. To characterize the Ex vivo condition, we used optogenetic stimulation of channelrhodopsin-(ChR2) expressing Cre/Ai32(ChR2-eYFP); Tph2-Cre/Ai32(ChR2-eYFP); Thi-Cre/Ai32(ChR2-eYFP) homozygous mice, which release acetylcholine, serotonin, and norepinephrine, respectively. With these mice it is possible to measure the transformation of eligibility traces into long-term changes by endogenous neuromodulators. Here we delineated that layer 2/3 neurons in the visual cortex showed no LTD after conditioning with paired-pulse low-frequency stimulation (ppLFS; 2Hz, 15 min). However, if conditioning was paired with acetylcholine, serotonin, or norepinephrine release upon 473 nm optical stimulation in brain slices, LTD occurs in every case. Thus, our data suggests a new pathway to connect the gap between stimulus and reward. Moreover, we found that stimulation by theta-glass or metal stimulators evoked IPSC traces with the same amplitudes but differences in decay kinetics, further questioning the appropriate use of stimulators in brain slices for evoking an event.


2009 ◽  
Vol 65 ◽  
pp. S81
Author(s):  
Masoumeh Kourosh Arami ◽  
Abdolrahman Sarihi ◽  
Bin Jiang ◽  
Tadaharu Tsumoto

2021 ◽  
Author(s):  
Tarek Jabri ◽  
Jason N MacLean

Complex systems can be defined by "sloppy" dimensions, meaning that their behavior is unmodified by large changes to specific parameter combinations, and "stiff" dimensions whose changes result in considerable modifications. In the case of the neocortex, sloppiness in synaptic architectures would be crucial to allow for the maintenance of spiking dynamics in the normal range despite a diversity of inputs and both short- and long-term changes to connectivity. Using simulations on neural networks with spiking matched to murine visual cortex, we determined the stiff and sloppy parameters of synaptic architectures across three classes of input (brief, continuous, and cyclical). Large-scale algorithmically-generated connectivity parameter values revealed that specific combinations of excitatory and inhibitory connectivity are stiff and that all other architectural details are sloppy. Stiff dimensions are consistent across a range of different input classes with self-sustaining synaptic architectures occupying a smaller subspace as compared to the other input classes. We also find that experimentally estimated connectivity probabilities from mouse visual cortex are similarly stiff and sloppy when compared to the architectures that we identified algorithmically. This suggests that simple statistical descriptions of spiking dynamics are a sufficient and parsimonious description of neocortical activity when examining structure-function relationships at the mesoscopic scale. Moreover, this study provides further evidence of the importance of the interrelationship of excitatory and inhibitory connectivity to establish and maintain stable spiking dynamical regimes in neocortex.


2016 ◽  
Author(s):  
Adam Ranson

SummaryActivity of neurons in primary sensory cortex is shaped by visual and behavioural context. However the long-term stability of the influence of contextual factors in the mature cortex remains poorly understood. To investigate this we used 2-photon calcium imaging to track the influence of surround suppression and locomotion on individual neurons over 14 days. We found that highly active excitatory neurons and PV+ interneurons exhibited relatively stable modulation by visual context. Similarly most neurons exhibited a stable yet distinct degree modulation by locomotion. In contrast less active excitatory neurons exhibited plasticity in visual context influence resulting in increased suppression. These findings suggest that the mature visual cortex possesses stable subnetworks of neurons, differentiated by cell-type and activity level, which have distinctive and stable interactions with sensory and behavioural context, as well as other less active and more labile neurons which are sensitive to visual experience.


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