Theoretical Neuroscience Podcast

The most prominent visual characteristic of neurons is their dendrites. Even more than 100 years after their first observation by Cajal, their function is not fully understood. Biophysical modeling based on cable theory is a key research tool for exploring putative functions, and today's guest is one the leading researchers in this field.    We talk about of passive and active dendrites, the kind...

The greatest mystery of all is why a group of atoms, like the ones constituting me, can feel anything.   The mind-brain problem has puzzled philosophers for millennia. Thanks to pioneers like Christof Koch, consciousness studies have recently become a legitimate field of scientific inquiry.    In this vintage episode, recorded in February 2021, we discuss many aspects of the phenomenon, including...

Computational neuroscientists use many software tools, and NEURON has become the leading tool for biophysical modeling of neurons and neural network. Today's guest has been the leading developer of NEURON since the infancy almost 50 years ago. We talk about how the tool got started and the development up until today's modern version of the software, including CoreNEURON optimized for parallel exec...

The idea that memories are stored in molecules was popular in the middle of the 20 th century.  However, since the discovery of long-term potentiation (LTP) in the 1970s, the dominant view has been that our memories are stored in synapses, that is, in the connections between neurons. Today, there are signs that the interest in molecular memory is returning, and the guest has presented a theory sug...

Is quantum physics important in determining how living systems, including brains, work? Today's guest is a professor of molecular genetics at the University of Surrey in England and explores this question in the book "Life at the edge: The coming of age of quantum biology". In this "vintage" episode, recorded in late 2019, we talk about how quantum physics is or may be key in photosynthesis, smell...

Most computational neuroscientists investigate electric dynamics in neurons or neural networks, but there is also computations going on inside neurons. Here the key dynamical variables are concentrations of numerous different molecules, and the signaling is typically done in cascades of chemical reactions, called signaling pathways. Today's guest is an expert in this kind of modelling and is parti...

Today's AI is largely based on supervised learning of neural networks using the backpropagation-of-error synaptic learning rule. This learning rule relies on differentiation of continuous activation functions and is thus not directly applicable to spiking neurons. Today's guest has developed the algorithm SuperSpike to address the problem. He has also recently developed a biologically more plausib...

Over the last ten years or so, the MindScope project at the Allen Institute in Seattle has pursued an industrylab-like approach to study the mouse visual cortex in unprecedented detail using electrophysiology, optophysiology, optical imaging and electron microscopy.  Together with collaborators at Allen, today's guest has worked to integrate of these data into large-scale neural network, and in th...

Today's guest is a pioneer both in the fields of computational neuroscience and artificial intelligence (AI) and has had a front seat during their development.  His many contributions include, for example, the invention of the Boltzmann machine with Ackley and Hinton in the mid 1980s.  In this "vintage" episode recorded in late 2019 he describes the joint births of these adjacent scientific fields...

Today's guest has argued that the present dominant way of doing systems neuroscience in mammals (large-scale electric or optical recordings of neural activity combined with data analysis) will be inadequate for understanding how their brain works. Instead, he proposes to focus on the simple roundworm C.elegans with only 302 neurons and try to reverse engineer it by means of optical stimulation and...

Over the last decade topological analysis has been established as a new tool for analysis of spiking data. Today's guest has been a pioneer in adapting this mathematical technique for use in our field and explains concepts and example applications.   We also also talk about so-called threshold-linear network model, a generalization of Hopfield networks exhibiting a much richer dynamics, where Cari...

Not all interesting network activity occurs in cortex. Networks in the spinal cord, the long thin tubular structure extending downwards from the neck, is responsible for setting up rhythmic motor activity needed for moving around. How do these so-called central pattern generators work? Today's guest has, together with colleagues in Copenhagen, developed a neuron-based network theory for how these...

We know a lot about of how neurons in the primary visual cortex (V1) of mammals respond to visual stimuli. But how does the vast information contained in the spiking of millions of neurons in V1 give rise to our visual percepts?  The guest's theory is that V1 acts as a "saliency detector" directing the gaze to the most important object in the visual scene. Then V1 in collaboration with higher visu...

A key goal of computational neuroscience is to build mathematical models linking single-neuron activity to systems-level activity. The guest has taken some bold steps in this direction by developing and exploring a multi-area model for the macaque visual cortex, and later also a model for the human cortex, using millions of simplified spiking neuron models.    We discuss the many design choices, t...

It is widely thought that spikes (action potentials) are the main carrier of information in the brain. But what is the neural code, that is, what aspects of the spike trains carry the information? The detailed temporal structure or maybe only the average firing rate?   And is there information in the correlation between spike trains in populations of similar neurons?   The guest has thought about...

Starting from the pioneering work of Hodgkin, Huxley and Rall in the 1950s and 60s, we have a well-founded biophysics-based mathematical understanding of how neurons integrate signals from other neurons and generate action potentials. Today's guest wrote the classic book "Biophysics of Computation" on the subject in 1998. We discuss its contents, what has changed in the last 25 years, and also tou...

The book "Models of the Mind" published in 2021 gives an excellent popular account of the history and questions of interest in theoretical neuroscience. I could think of no other person more suitable to invite for the inaugural episode of the podcast than its author Grace Lindsay. In the podcast we discuss highlights from the book as well as recent developments and the future of our field.