Retinotopy

Primary sensory brain areas contain innate stereotyped topographies like retinotopy and somatotopy, but evidence of similar topographies underlying abstract cortical representations remains equivocal. Experience-driven self-organization provides a complementary mechanism for neural circuit development which instead yields conserved features like orientation tuning, but has also mainly been studied in sensory cortices or artificial neural networks (ANNs). Here we pursue a high level perspective on conservation of topographies and feature spaces throughout the cortex using blood oxygen level d

Astrocytes are dynamic cells that closely interact with neurons and play major roles in brain functions. Although their involvement in sensory processing has been highlighted in different brain regions, their contribution to vision processing remains poorly explored in the superior colliculus (SC), a central structure of the mouse visual system. We here report that astrocytes from the retinorecipient layers of the SC form particularly extensive networks that are mediated by stronger expression of the gap-junction connexins 30 and 43, compared to astrocytes from other brain areas. Furthermore,

Neural population signals recorded with magneto- (MEG) or electroencephalography (EEG) contain information about viewed natural images and their categories. However, it remains unclear which specific visual features contribute to this information. To address this, we applied spectral manipulations and different texturization algorithms to natural images of various categories and recorded MEG in human subjects presented with these stimuli. The employed stimulus space allowed us to attribute components of visual information to specific low-, mid- and high-level visual features. Furthermore, this

Functional ultrasound imaging (fUSI) can record neuronal activity down to 20 mm depth in the brain, at finer resolution than functional magnetic resonance imaging. We developed an acquisition add-on, analysis and visualization pipeline that allows efficient identification of anatomical and functional layout of the brain in 3D. Leveraging the high signal quality of fUSI, we asked whether the acquisition of multi-cm 3D functional maps can be made compatible with chronic anesthetized experiment design. Since availability of large-brained species is low and their behavioral training can be prohibi

Cortical visual prostheses are designed to restore vision by stimulating neurons, inducing visual perceptions in people with impaired vision. To obtain useful visual perception, it is essential to induce, through stimulation, activity that closely mimics that of natural vision. Existing V1 prostheses stimulation strategies primarily focus on retinotopic stimulation, overlooking other important encoding properties and thereby failing to replicate the complex neural activity patterns of natural vision. Our work introduces a novel stimulation protocol that targets cortical tissue according to bot

Multisensory integration requires transformations between coordinate systems. When an object is touched and seen at the same time, tactile signals from the snout’s vibrissae arrive in the somatotopically organized primary whisker somatosensory cortex (wS1) whereas visual signals arrive in the retinotopically organized primary visual cortex (V1). The posterior parietal cortex (PPC) in-between is a candidate cortical region for merging these two representations. However, how converging visual and tactile inputs of nearby objects are processed in these cortical areas remains unclear. To address t

Retinotopy is generally preserved across the visual system, but its cellular-level organization remains elusive. How precisely is topographic information transmitted from the retina? To address this question, here we combined experimental and computational modelling approaches. First, using two-photon calcium imaging of retinal ganglion cell (RGC) axons as well as local neurons in the superior colliculus (SC), we performed functional mapping of the retinocollicular projection at a single-cell resolution in awake mice. The tiling patterns of RGC axon terminals and their corresponding receptive

Information is encoded in fine-scale functional topographies that vary from brain to brain. Hyperalignment models information that is shared across brain in a high-dimensional common information space. Hyperalignment transformations project idiosyncratic individual topographies into the common model information space. These transformations contain topographic basis functions, affording estimates of how shared information in the common model space is instantiated in the idiosyncratic functional topographies of individual brains. This new model of the functional organization of cortex – as m

…preference map (OPM) with a retinotopy-based concentric pattern (Ahmadlou and Heimel, 2015; Feinberg and Meister, 2015; but see Chen et al., 2020). The underlying developmental mechanisms that give rise to this concentric OPM in the mouse SC are still unclear. During visual system development, the stage III (S3) retinal waves are known to play important roles in circuit formation. Specifically, the S3 waves that tend to propagate towards the caudal direction (Gribizis et al., 2019) have impacts on the directio

Topographic maps are a prominent feature of brain organization, reflecting local and large-scale representation of the sensory surface. ​​Traditionally, such representations in early visual areas are conceived as retinotopic maps preserving ego-centric retinal spatial location while ensuring that other features of visual input are uniformly represented for every location in space. I will discuss our recent findings of a striking departure from this simple mapping in the secondary visual area (V2) of the tree shrew that is best described as a sinusoidal transformation of the visual field. This