Topic: olfactory bulb

The capacities to learn and to store memories are two of the most important functions of the brain, but these abilities are inherently at odds with each other. On one hand, a neuronal network must be flexible enough to quickly store new information, but on the other it must be stable enough to prevent old memories from being constantly overwritten. Metaplasticity in which the timescale of synaptic modifications made by an individual neuron changes could resolve this flexibility-stability tradeoff. We propose that this strategy may be implemented in the olfactory bulb (OB). A striking, characte

Neural activity in many sensory systems is organized on low-dimensional manifolds by means of convex receptive fields. Neural codes in these areas are constrained by this organization, as not every neural code is compatible with convex receptive fields. The same codes are also constrained by the structure of the underlying neural network. In my talk I will attempt to provide answers to the following natural questions: (i) How do recurrent circuits generate codes that are compatible with the convexity of receptive fields? (ii) How can we utilize the constraints imposed by the convex receptive

Cognitive processing requires directed interactions between several brain areas of the limbic system, such as the hippocampus (HP) and lateral entorhinal cortex (LEC). They are modulated by multiple sensory systems. During development, the olfactory system might have a particular impact on these areas in mice that at birth are blind, deaf, do not whisker and have poor motor abilities. We previously showed that neonatal olfactory activation boosts the oscillatory entrainment of LEC via mono-and polysynaptic projections from the olfactory bulb (OB). However, the long-lasting impact of olfactory

Can alterations in experience trigger different plastic modifications in neuronal structure and function, and if so, how do they integrate at the cellular level? To address this question, we interrogated circuitry in the mouse olfactory bulb responsible for the earliest steps in odor processing. We induced experience-dependent plasticity in mice of either sex by blocking one nostril for one day, a minimally invasive manipulation that leaves the sensory organ undamaged and is akin to the natural transient blockage suffered during common mild rhinal infections. We found that such brief sensory d

Neural stem cells reside in the adult mammalian brain. The ventricular-subventricular zone (V-SVZ) gives rise to olfactory bulb neurons, as well as small numbers of glia throughout life. Adult V-SVZ neural stem cells dynamically integrate intrinsic and extrinsic signals to either maintain the quiescent state or to become activated to divide and generate progeny. I will present our recent findings highlighting adult neural stem cell heterogeneity, including the identification of novel gliogenic domains and cell types, and the key roles of physiological state and long-range signals in the regula

In the olfactory system, cholinergic modulation has been associated with contrast modulation and changes in receptive fields in the olfactory bulb, as well the learning of odor associations in the olfactory cortex. Computational modeling and behavioral studies suggest that cholinergic modulation could improve sensory processing and learning while preventing pro-active interference when task demands are high. However, how sensory inputs and/or learning regulate incoming modulation has not yet been elucidated. We here use a computational model of the olfactory bulb, piriform cortex (PC) and hori

Olfaction facilitates a large variety of animal behaviors such as feeding, mating, and communication. In the mammal olfactory system, the olfactory bulb (OB) and piriform cortex (PCx) are responsible for preliminary odor encoding and corresponding memory storage respectively. Recent evidence demonstrated the dynamic nature of OB and PCx odor representations upon frequent repetition of the same odors over days, and this phenomenon, termed representational drift, should be the consequence of highly plastic nature of biologically constrained synapses in the olfactory system. In this work, we buil

Understanding the neural mechanisms underlying odor representation and memory in the olfactory bulb (OB) is critical for advancing our knowledge of sensory processing and neural plasticity. Inspired by in vivo experimental findings [1, 2], we applied the eligibility propagation (e-prop) learning rule [3] to simulate the cholinergic and GABAergic responses to distinct odors. [1, 2] found differential activation patterns in glomeruli of the OB in response to different odor exposures. The modulation of activity by cholinergic and GABAergic projections from the horizontal diagonal band (HDB) was s