Biology subjects

Hübener, M.

Publications and source records attributed to Hübener, M..

7 recordsLinked to original sources

bioRxiv2023

Sensory experience steers representational drift in mouse visual cortex

Representational drift - the gradual continuous change of neuronal representations - has been observed across many brain areas. It is unclear whether drift is caused by synaptic plasticity elicited by sensory experience, or by the intrinsic volatility of synapses. Here, using chronic two-photon calcium imaging in mouse primary visual cortex, we find that the preferred stimulus orientation of individual neurons slowly drifts over the course of weeks. By using cylinder lens goggles to limit visual experience to a narrow range of orientations, we show that the direction of drift, but not its magnitude, is biased by the statistics of visual input. A network model suggests that drift of preferred orientation largely results from synaptic volatility, which under normal visual conditions is counteracted by experience-driven Hebbian mechanisms, stabilizing preferred orientation. Under deprivation conditions these Hebbian mechanisms enable adaptation. Thus, Hebbian synaptic plasticity steers drift to match the statistics of the environment.

neuroscience↗

bioRxiv2023

Ocular dominance columns in mouse visual cortex

The columnar organization of response properties is a fundamental feature of the mammalian visual cortex. However, columns have not been observed universally across all mammalian species. Here, we report the discovery of ocular dominance columns in mouse visual cortex. Our observation in this minute cortical area sets a new boundary condition for models explaining the emergence of columnar organizations in the neocortex.

neuroscience↗

bioRxiv2020

Spaced training enhances memory and prefrontal ensemble stability in mice.

Memory is substantially improved when learning is distributed over time, an effect called "spacing effect". So far it has not been studied how spaced learning affects neuronal ensembles presumably underlying memory. In the present study, we investigate whether trial spacing increases the stability or size of neuronal ensembles. Mice were trained in the "everyday memory" task, an appetitive, naturalistic, delayed matching-to-place task. Spacing trials by 60 minutes produced more robust memories than training with shorter or longer intervals. c-Fos labeling and chemogenetic inactivation established the necessity of the dorsomedial prefrontal cortex (dmPFC) for successful memory storage. In vivo calcium imaging of excitatory dmPFC neurons revealed that longer trial spacing increased the similarity of the population activity pattern on subsequent encoding trials and upon retrieval. Conversely, trial spacing did not affect the size of the total neuronal ensemble or the size of subpopulations dedicated to specific task-related behaviors and events. Thus, spaced learning promotes reactivation of prefrontal neuronal ensembles processing episodic-like memories.

neuroscience↗

bioRxiv2020

Selective connectivity limits functional binocularity in the retinogeniculate pathway of the mouse

Eye-specific segregation of retinal ganglion cell (RGC) axons in the dorsal lateral geniculate nucleus (dLGN) is considered a hallmark of visual system development. However, a recent anatomical study showed that nearly half of the neurons in dLGN of adult mice still receive input from both retinae, but functional data about binocularity in mature dLGN is conflicting. Here, we found that a variable but small fraction of thalamocortical neurons is binocular in vivo. Using dual-channel optogenetics in vitro we correspondingly found that dLGN neurons are dominated by retinogeniculate input from one eye only, although most neurons also received small but detectable input from the non-dominant eye. Anatomical overlap between RGC axons and dLGN neuron dendrites did not explain this strong bias towards monocularity. Our data rather suggest that functional input selection and refinement, leaving the remaining non-dominant eye inputs in a juvenile-like state, underlies the prevalent monocularity of neurons in dLGN.

neuroscience↗

bioRxiv2020

Colors everywhere: enhanced chromatic processing across the first visual synapse in the zebrafish central brain

Larval zebrafish (Danio rerio) are an ideal organism to study color vision, as their eye possesses four types of cone photoreceptors, covering most of the visible range and into the UV [1,2]. Additionally, their entire eye and nervous system are accessible to imaging, given they are naturally transparent [3-5]. Relying on this advantage, recent research has found that, through a set of color specific horizontal, bipolar and retinal ganglion cells (RGCs) [6-8], the eye then relays tetrachromatic information to several retino-recipient areas (RAs) [9,10]. The main RA is the optic tectum, receiving 97% of the RGC axons via the neuropil mass termed Arborization Field 10 (AF10) [11,12]. In this work, we aim to understand the processing of color signals at the interface between RGCs and their targets in the brain. We used 2-photon calcium imaging to separately measure the responses of RGCs and neurons in the dorsal brain to stimulation with four different colors in awake animals. We find that color information is widespread throughout the larval brain, with a large variety of color responses among RGCs, and an even greater diversity in their targets. Specific combinations of response types are localized to specific nuclei, but we observe no single color processing structure. In the main interface in this pathway, the connection between Arborization Field 10 and the tectum, we observe key elements of color processing such as enhanced signal decorrelation and improved decoding [13,14]. Finally, when presenting a richer set of stimuli, we identify parallel processing of color, motion and luminance information in the same cells/terminals, evidence of a rich color vision machinery in this small vertebrate brain.

neuroscience↗

bioRxiv2020

Disparity sensitivity and binocular integration in mouse visual cortex areas

Binocular disparity, the difference between the two eyes images, is a powerful cue to generate the three-dimensional depth percept known as stereopsis. In primates, binocular disparity is processed in multiple areas of the visual cortex, with distinct contributions of higher areas to specific aspects of depth perception. Mice, too, can perceive stereoscopic depth, and neurons in primary visual cortex (V1) and higher-order, lateromedial (LM) and rostrolateral (RL) areas were found to be sensitive to binocular disparity. A detailed characterization of disparity tuning properties across mouse visual areas is lacking, however, and acquiring such data might help clarifying the role of higher areas for disparity processing and establishing putative functional correspondences to primate areas. We used two-photon calcium imaging to characterize the disparity tuning properties of neurons in mouse visual areas V1, LM, and RL in response to dichoptically presented binocular gratings, as well as correlated and anticorrelated random dot stereograms (RDS). In all three areas, many neurons were tuned to disparity, showing strong response facilitation or suppression at optimal or null disparity, respectively. This was even the case in neurons classified as monocular by conventional ocular dominance measurements. Spatial clustering of similarly tuned neurons was observed at a scale of about 10 m. Finally, we probed neurons sensitivity to true stereo correspondence by comparing responses to correlated and anticorrelated RDS. Area LM, akin to primate ventral visual stream areas, showed higher selectivity for correlated stimuli and reduced anticorrelated responses, indicating higher-level disparity processing in LM compared to V1 and RL.

neuroscience↗

bioRxiv2019

Area-specific mapping of binocular disparity across mouse visual cortex

Binocular disparity, the difference between left and right eye images, is a powerful cue for depth perception. Many neurons in the visual cortex of higher mammals are sensitive to binocular disparity, with distinct disparity tuning properties across primary and higher visual areas. Mouse primary visual cortex (V1) has been shown to contain disparity-tuned neurons, but it is unknown how these signals are processed beyond V1. We find that disparity signals are prominent in higher areas of mouse visual cortex. Preferred disparities markedly differ among visual areas, with area RL encoding visual stimuli very close to the mouse. Moreover, disparity preference is systematically related to visual field elevation, such that neurons with receptive fields in the lower visual field are overall tuned to near disparities, likely reflecting an adaptation to natural image statistics. Our results reveal ecologically relevant areal specializations for binocular disparity processing across mouse visual cortex.

neuroscience↗