Abstract:Predictive coding has been identified as a major driver of computation and learning in corticalmicrocircuits. But it has remained unknown which synaptic plasticity processes install and maintain predictive coding capability. Predictions are inherently uncertain, and learning rules that aim at discriminating linearly separable classes of inputs - such as the perceptron learning rule - are not suitable for learning to predict. We show that experimental data on synaptic plasticity in distal dendrites of pyramidal… Show more
“…These works however did not consider synaptic clustering in the context of associative learning as we did. The work by Rao et al ( 2022 ) developed a plasticity rule termed Dendritic Logistic Regression that enables the apical compartment to predict somatic activity. This objective is somewhat related to our association objective, although we did not attempt to produce a precise probabilistic prediction as in Rao et al ( 2022 ).…”
Section: Discussionmentioning
confidence: 99%
“…The work by Rao et al ( 2022 ) developed a plasticity rule termed Dendritic Logistic Regression that enables the apical compartment to predict somatic activity. This objective is somewhat related to our association objective, although we did not attempt to produce a precise probabilistic prediction as in Rao et al ( 2022 ). The authors of this paper also did not consider a clustering objective, hence activity in their model for a given apical activation is distributed over all branches.…”
Section: Discussionmentioning
confidence: 99%
“…These works however did not consider synaptic clustering in the context of associative learning as we did. The work by Rao et al (2022) developed a plasticity rule termed . /fnins.…”
The unique characteristics of neocortical pyramidal neurons are thought to be crucial for many aspects of information processing and learning in the brain. Experimental data suggests that their segregation into two distinct compartments, the basal dendrites close to the soma and the apical dendrites branching out from the thick apical dendritic tuft, plays an essential role in cortical organization. A recent hypothesis states that layer 5 pyramidal cells associate top-down contextual information arriving at their apical tuft with features of the sensory input that predominantly arrives at their basal dendrites. It has however remained unclear whether such context association could be established by synaptic plasticity processes. In this work, we formalize the objective of such context association learning through a mathematical loss function and derive a plasticity rule for apical synapses that optimizes this loss. The resulting plasticity rule utilizes information that is available either locally at the synapse, through branch-local NMDA spikes, or through global Ca2+events, both of which have been observed experimentally in layer 5 pyramidal cells. We show in computer simulations that the plasticity rule enables pyramidal cells to associate top-down contextual input patterns with high somatic activity. Furthermore, it enables networks of pyramidal neuron models to perform context-dependent tasks and enables continual learning by allocating new dendritic branches to novel contexts.
“…These works however did not consider synaptic clustering in the context of associative learning as we did. The work by Rao et al ( 2022 ) developed a plasticity rule termed Dendritic Logistic Regression that enables the apical compartment to predict somatic activity. This objective is somewhat related to our association objective, although we did not attempt to produce a precise probabilistic prediction as in Rao et al ( 2022 ).…”
Section: Discussionmentioning
confidence: 99%
“…The work by Rao et al ( 2022 ) developed a plasticity rule termed Dendritic Logistic Regression that enables the apical compartment to predict somatic activity. This objective is somewhat related to our association objective, although we did not attempt to produce a precise probabilistic prediction as in Rao et al ( 2022 ). The authors of this paper also did not consider a clustering objective, hence activity in their model for a given apical activation is distributed over all branches.…”
Section: Discussionmentioning
confidence: 99%
“…These works however did not consider synaptic clustering in the context of associative learning as we did. The work by Rao et al (2022) developed a plasticity rule termed . /fnins.…”
The unique characteristics of neocortical pyramidal neurons are thought to be crucial for many aspects of information processing and learning in the brain. Experimental data suggests that their segregation into two distinct compartments, the basal dendrites close to the soma and the apical dendrites branching out from the thick apical dendritic tuft, plays an essential role in cortical organization. A recent hypothesis states that layer 5 pyramidal cells associate top-down contextual information arriving at their apical tuft with features of the sensory input that predominantly arrives at their basal dendrites. It has however remained unclear whether such context association could be established by synaptic plasticity processes. In this work, we formalize the objective of such context association learning through a mathematical loss function and derive a plasticity rule for apical synapses that optimizes this loss. The resulting plasticity rule utilizes information that is available either locally at the synapse, through branch-local NMDA spikes, or through global Ca2+events, both of which have been observed experimentally in layer 5 pyramidal cells. We show in computer simulations that the plasticity rule enables pyramidal cells to associate top-down contextual input patterns with high somatic activity. Furthermore, it enables networks of pyramidal neuron models to perform context-dependent tasks and enables continual learning by allocating new dendritic branches to novel contexts.
“…The synaptic plasticity rule utilized in (Legenstein and Maass, 2011) and (Limbacher and Legenstein, 2020) is spike time dependent plasticity rule. In a recent study, Rao et al (2022) employ Dendritic Logistic Regression to define connection weights. Furthermore Moldwin and Segev (2020) used perceptron rule to define synaptic connection weights.…”
Pyramidal cells are the most prevalent neuronal type in the cortex, receiving thousands of synaptic inputs from all over the brain, and sending the largest axon outputs. They have a variety of active conductivities and complex morphologies that support highly nonlinear dendritic calculations. There has been a growing interest in understanding the classification abilities of pyramidal neurons. The perceptron learning algorithm, one of the foundations of machine learning, uses the highly simplified mathematical abstraction of a neuron, and it is unclear to what extent real biophysical neurons can perform perceptron like learning. In this article, we investigated the performance of a pyramidal neuron model in the classification problem of a two-class ECG dataset for different synaptic regions by using the perceptron learning method. The main purpose of this study is to reveal what role the soma, basilar and apical dendrites play in a classification problem. We concluded that when the synaptic receptor locations are selected close to the soma, classification performance close to Perceptron Learning in a Cortical Pyramidal Neuron Model the single layer perceptron can be obtained. The results indicated that the pyramidal neuron can successfully classify real-world data.
Pyramidal cells are the most prevalent neuronal type in the cortex, receiving thousands of synaptic inputs from all over the brain, and sending the largest axon outputs. They have a variety of active conductivities and complex morphologies that support highly nonlinear dendritic calculations. There has been a growing interest in understanding the classification abilities of pyramidal neurons. The perceptron learning algorithm, one of the foundations of machine learning, uses the highly simplified mathematical abstraction of a neuron, and it is unclear to what extent real biophysical neurons can perform perceptron like learning. In this article, we investigated the performance of a pyramidal neuron model in the classification problem of a two-class ECG dataset for different synaptic regions by using the perceptron learning method. The main purpose of this study is to reveal what role the soma, basilar and apical dendrites play in a classification problem. We concluded that when the synaptic receptor locations are selected close to the soma, classification performance close to the single layer perceptron can be obtained. The results indicated that the pyramidal neuron can successfully classify real-world data.
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