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Poleg-Polsky, A.

Publications and source records attributed to Poleg-Polsky, A..

2 recordsLinked to original sources

Dendritic spikes expand the range of well-tolerated population noise structures

The brain operates surprisingly well despite the noisy nature of individual neurons. The central mechanism for noise mitigation in the nervous system is thought to involve averaging over multiple noise-corrupted inputs. Subsequently, there has been considerable interest recently to identify noise structures that can be averaged out to preserve reliable signal encoding. By analyzing realistic synaptic integration in biophysically accurate neuronal models, I report a role for a complementary de-noising approach mediated by focal dendritic spikes. Dendritic spikes might seem unlikely candidates for noise reduction due to their miniscule integration compartments and poor averaging abilities. Nonetheless, the extra thresholding step introduced by dendritic spike generation could increase neuronal tolerance for a broad category of noise structures, some of which cannot be resolved well with averaging. Computations with multiple dendritic spikes compensate for compartment size constraints and expand the repertoire of conditions that can be reliably processed by neuronal populations.

neuroscience

NMDA spikes mediate amplification of odor pathway information in the piriform cortex

The piriform cortex (PCx) receives direct input from the olfactory bulb (OB) and is the brains main station for odor recognition and memory. The transformation of the odor code from OB to PCx is profound: mitral and tufted cells in olfactory glomeruli respond to individual odorant molecules, whereas pyramidal neurons (PNs) in the PCx responds to multiple, apparently random combinations of activated glomeruli. How these \"discontinuous\" receptive fields are formed from OB inputs remains unknown. Counter to the prevailing view that olfactory PNs sum their inputs passively, we show for the first time that NMDA spikes within individual dendrites can both amplify OB inputs and impose combination selectivity upon them, while their ability to compartmentalize voltage signals allows different dendrites to represent different odorant combinations. Thus, the 2-layer integrative behavior of olfactory PN dendrites provides a parsimonious account for the nonlinear remapping of the odor code from bulb to cortex.

neuroscience