Biology subjects

van der Togt, C.

Publications and source records attributed to van der Togt, C..

4 recordsLinked to original sources

bioRxiv2023

Visuomotor experience induces functional and structural plasticity of chandelier cells

Detailed characterization of interneuron types in primary visual cortex (V1) has greatly contributed to understanding visual perception, yet the role of chandelier cells (ChCs) in visual processing remains poorly characterized. Using viral tracing we found that V1 ChCs predominantly receive monosynaptic input from local layer 5 pyramidal cells and higher-order cortical regions. Two-photon calcium imaging and convolutional neural network modelling revealed that ChCs are visually responsive but weakly selective for stimulus content. In mice running in a virtual tunnel, ChCs respond strongly to events known to elicit arousal, including locomotion and visuomotor mismatch. Repeated exposure of the mice to the virtual tunnel was accompanied by reduced visual responses of ChCs and structural plasticity of ChC boutons and axon initial segment length. Finally, ChCs only weakly inhibited pyramidal cells. These findings suggest that ChCs provide an arousal-related signal to layer 2/3 pyramidal cells that may modulate their activity and/or gate plasticity of their axon initial segments during behaviorally relevant events.

neuroscience↗

bioRxiv2020

SpecSeg: cross spectral power-based segmentation of neurons and neurites in chronic calcium imaging datasets

Imaging calcium signals in neurons of awake, behaving animals using single- or multi-photon microscopy facilitates the study of coding in large neural populations. Such experiments produce massive datasets requiring powerful methods to extract responses from hundreds of neurons. We present SpecSeg, a new open-source toolbox for 1) segmentation of regions of interest (ROIs) representing neuronal structures, 2) inspection and manual editing of ROIs, 3) neuropil correction and signal extraction and 4) matching of ROIs in sequential recordings. SpecSeg uses a novel method for ROI registration, based on temporal cross-correlations of low-frequency components derived by Fourier analysis, of each pixel with its neighbors. The approach is insightful and enables ROI detection around neurons or neurites. It works for single- (miniscope) and multi-photon microscopy data, eliminating the need for separate toolboxes. SpecSeg thus provides an efficient and user-friendly approach for analyzing calcium responses in neuronal structures imaged over prolonged periods of time.

neuroscience↗

bioRxiv2018

Feedforward and feedback processing during figure-ground perception in mice

The segregation of figures from the background is an important step in visual perception. In primary visual cortex, figures evoke stronger activity than backgrounds during a delayed phase of the neuronal responses, but it is unknown how this figure-ground modulation (FGM) arises and whether it is necessary for perception. Here we show, using optogenetic silencing in mice, that the delayed V1 response phase is necessary for figure-ground segregation. Neurons in higher visual areas also exhibit FGM and optogenetic silencing of higher areas reduced FGM in V1. In V1, figures elicited higher activity of vasoactive intestinal peptide-expressing (VIP) interneurons than the background, whereas figures suppressed somatostatin-positive interneurons, resulting in an increased activation of pyramidal cells. Optogenetic silencing of VIP neurons reduced FGM in V1, indicating that disinhibitory circuits contribute to FGM. Our results provide new insight in how lower and higher areas of the visual cortex interact to shape visual perception.

neuroscience↗

bioRxiv2017

Electrochemical Measurement Of Acetylcholine In The Dorsolateral Prefrontal Cortex: A Technical Report

Ever since the discovery of acetylcholine in 1913, its role as neuromodulator has been extensively studied in a variety of model systems. These previous studies revealed that acetylcholine is of critical importance for several cognitive functions including attention, learning and memory. In spite of these previous findings, it has proven difficult to determine the amount of acetylcholine that is released during cognitive tasks with sub-second temporal resolution. One method that might be used to measure acetylcholine release is the use of an enzyme-coupled amperometric sensor, which has been suggested to measure acetylcholine with high sensitivity, selectivity and relatively high temporal resolution (< 1 second). In the present study, we have tried to adapt the technique developed in the rodent model system by Parikh and colleagues1,2 for use in non-human primates. We aimed to measure in-vivo levels of acetylcholine in the macaque dorsolateral prefrontal cortex while the monkey performed an attention demanding curve-tracing task3,4. We report that our attempts to measure acetylcholine using amperometry in an awake behaving macaque monkey proved difficult and tedious and that our results are inconsistent and prone to noise. In the discussion, we will outline the challenges that will need to be addressed to use this technique in non-human primates and hope that our observations inspire solutions to help future research on the role of this important neurotransmitter.

neuroscience↗