Jonathan R. Whitlock's research while affiliated with Norwegian University of Science and Technology and other places

Publications (18)

Preprint
A bstract The cortical population code is pervaded by activity patterns evoked by movement, but how such signals relate to the natural actions of unrestrained animals remains largely unknown, particularly in sensory areas. To address this we compared high-density neural recordings across four cortical regions (visual, auditory, somatosensory, motor...
Preprint
Full-text available
The need for anatomical registration and visualization tools is greater than ever thanks to novel technologies that allow users to record from thousands of neurons across multiple brain regions simultaneously. The vast majority of digital reconstruction toolkits for rodent models were developed using mouse brain atlases, leaving few options for tho...
Article
Full-text available
The posterior parietal cortex (PPC) and frontal motor areas comprise a cortical network supporting goal-directed behaviour, with functions including sensorimotor transformations and decision making. In primates, this network links performed and observed actions via mirror neurons, which fire both when individuals perform an action and when they obs...
Article
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Recent investigations of the rat posterior parietal cortex (PPC) suggest that this region plays a central role in action control together with the frontal cortical areas. Posterior parietal-frontal cortical connections have been described in rats, but little is known about whether these connections are topographically organized as in the primate. H...
Preprint
The posterior parietal cortex (PPC), along with anatomically linked frontal areas, form a cortical network which mediates several functions that support goal-directed behavior, including sensorimotor transformations and decision making. In primates, this network also links performed and observed actions via mirror neurons, which fire both when an i...
Article
The posterior parietal cortex (PPC) is a multifaceted region of cortex, contributing to several cognitive processes including sensorimotor integration and spatial navigation. Although recent years have seen a considerable rise in the use of rodents, particularly mice, to investigate PPC and related networks, a coherent anatomical definition of PPC...
Article
Animals constantly update their body posture to meet behavioral demands, but little is known about the neural signals on which this depends. We therefore tracked freely foraging rats in three dimensions while recording from the posterior parietal cortex (PPC) and the frontal motor cortex (M2), areas critical for movement planning and navigation. Bo...
Preprint
Full-text available
The posterior parietal cortex (PPC) is a multifaceted region of cortex, contributing to several cognitive processes including sensorimotor integration and spatial navigation. Although recent years have seen a considerable rise in the use of rodents, particularly mice, to investigate PPC and related networks, a coherent anatomical definition of PPC...
Preprint
Full-text available
In order to meet physical and behavioural demands of their environments animals constantly update their body posture, but little is known about the neural signals on which this ability depends. To better understand the role of cortex in coordinating natural pose and movement, we tracked the heads and backs of freely foraging rats in 3D while record...
Article
Neural correlates of movement planning have been studied most commonly using signals isolated from single cells. However, in this issue of Neuron, Wilber et al. (2017) show that movement trajectories are encoded and replayed in the collective activity of thousands of cells at a time in the posterior parietal cortex.
Article
The posterior parietal cortex, along with temporal and prefrontal cortices, is one of the three major associative regions in the cortex of the mammalian brain. It is situated between the visual cortex at the caudal pole of the brain and the somatosensory cortex just behind the central sulcus. Technically, any cortex covered by the parietal bone is...
Article
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[This corrects the article on p. 293 in vol. 8, PMID: 24860475.].
Article
Full-text available
The posterior parietal cortex (PPC) participates in a manifold of cognitive functions, including visual attention, working memory, spatial processing, and movement planning. Given the vast interconnectivity of PPC with sensory and motor areas, it is not surprising that neuronal recordings show that PPC often encodes mixtures of spatial information...
Article
Full-text available
Areas encoding space in the brain contain both representations of position (place cells and grid cells) and representations of azimuth (head direction cells). Previous studies have already suggested that although grid cells and head direction cells reside in the same brain areas, the calculation of head direction is not dependent on the calculation...
Article
Posterior parietal cortex (PPC) and medial entorhinal cortex (MEC) are important elements of the neural circuit for space, but whether representations in these areas are controlled by the same factors is unknown. We recorded single units simultaneously in PPC and MEC of freely foraging rats and found that a subset of PPC cells are tuned to specific...
Article
To determine whether entorhinal spatial representations are continuous or fragmented, we recorded neural activity in grid cells while rats ran through a stack of interconnected, zig-zagged compartments of equal shape and orientation (a hairpin maze). The distribution of spatial firing fields was markedly similar across all compartments in which run...
Article
Full-text available
The navigational system of the mammalian cortex comprises a number of interacting brain regions. Grid cells in the medial entorhinal cortex and place cells in the hippocampus are thought to participate in the formation of a dynamic representation of the animal's current location, and these cells are presumably critical for storing the representatio...

Citations

... As the techniques for neuro-histology have improved and their scale of use has increased, development in the methods used for registering and quantifying histology data within existing, standardized atlas spaces has become necessary. While automated cell counting options exist (Brey et al., 2003;Kopec et al., 2011;Schüffler et al., 2013;Morriss et al., 2020;Courtney et al., 2021;Paglia et al., 2021;Sekar et al., 2021), few take into consideration the unbiased approach of whole-brain mapping, thus requiring a pipeline for cell counting that includes registering histology to border-defined structures in the whole brain. In the context of whole-brain imaging and mapping, where the volume of data is exceedingly large, the need for these processes to become automated has become apparent. ...
... UMAP is a nonlinear manifold learning technique that is constructed from a theoretical framework based on topological data analysis, Riemannian geometry and algebraic topology (McInnes et al, 2018) and it is also been used on neural data both as a NML method (Tombaz et al, 2020) and for broader dimensionality reduction purposes Lee et al (2021). It builds upon the mathematical foundations of LEM, Isomap and other nonlinear manifold learning techniques in that it uses a k nearest neighbours weighted graphs representation of the data. ...
... Such parallel pathways likely exist given the necessity for somatotopic organization in the frontal motor areas. Consistent with this idea, an anatomical examination of the frontoparietal network in rats and mice found that all PPC subdivisions are strongly connected with the frontal area M2 in a topographically organized manner and largely reciprocate the densest input stems from the same areas (Sreenivasan et al., 2016;Zhang et al., 2016;Itokazu et al., 2018;Olsen et al., 2019). This anatomical configuration may exist to support the parallel organization of effector-specific frontoparietal connections. ...
... To help delineate the injection sites, we superimposed the fluorescence and Nissl images and adjusted their contrast and brightness in Adobe Photoshop. We delineated all areas following (Paxinos and Franklin, 2019), except for PPC that was delineated following (Hovde et al., 2018). ...
... MDS is then applied to the matrix of shortest path lengths within the graph D G = {d G (i, j)} to yield an embedding of the data in a k-dimensional Euclidean space Y that best preserves the manifold's estimated geometry. The quality of the reconstructed manifold Y depends greatly on the size of the neighbourhood search and the distance metric used to build G. Isomap is a conservative approach that seems well suited to tackle the non-linearity inherent to neural dynamics and it has in fact been used in a variety of studies, even just for visualisation purposes (Mimica et al, 2018;Chaudhuri et al, 2019;Sun et al, 2019). ...
... The PPC utilizes sensory feedback as well as the efferent copy provided by the cerebellum to maintain an internal representation of limb positions and the body in space, what could be described as body ownership or the body schema (Amino et al., 2001;Dijkerman and de Haan, 2007;Kammers et al., 2009;Parkinson et al., 2010;van Stralen et al., 2011). Recent publications have even gone so far as to identify the PPC as the home for the ''posture cells of the brain'' (Chen, 2018;Mimica et al., 2018). The current study reinforces the notion of the bilateral PPC's role in monitoring and updating the internal representation. ...
... Motor function. It has been shown that movement trajectories are encoded by the collective activity of thousands of neurons in the posterior parietal cortex [33,34]. In monkeys with arrays of electrodes chronically implanted into the frontal and parietal cortex, a significant individual variability in the activity of individual neurons and a significant stability of the ensemble response when performing the task of continuous limb movement were found [35]. ...
... Brain imaging studies have shown that the parietal lobe is activated by various stimuli, including visual, vestibular, and somatosensory stimuli. The posterior parietal cortex (PPC) has been reported to be involved in information processing in the brain in relation to the integration of these multisensory systems [2]. In previous studies, the right parietal area was reported to be activated by visual inputs such as optokinetic stimulation and fixation of visual targets [3,4], while the left PPC was activated by somatosensory inputs such as light touch from a stable external spatial reference [5], vestibular inputs such as caloric stimulation [6], or galvanic vestibular stimulation (GVS) [7]. ...
... [5][6][7] For example, mice respond with freezing to a sweeping object flying overhead 2 but with pursuit hunting to a similar object moving at ground level, 3 suggesting that selection of the appropriate action requires integration of head and body positioning with the visual input. This process of integration has traditionally been studied at high levels of the hierarchical visual pathway (e.g., posterior parietal cortex 8,9 ; rodent lateral posterior thalamus and primate pulvinar 10,11 ). Spontaneous and visually evoked activity in primary visual cortex has also been shown to be strongly affected by locomotion in head-fixed preparations [12][13][14][15] and head rotations along different axes in freely moving animals. ...
... Locomotion exerts a variable influence on the positional specificity of MEC cells 73 and competes with the influence of optic flow information to drive grid cell periodicity 74 . In addition, head direction cells can decouple from the grid network in linearized environments, maintaining allocentric orientation to room cues while grid cells reorient 58,[75][76][77][78] . This finding is contrary to the expectation of the PI-CAN model since static coupling between head direction and grid cells is posited to support path integration calculations irrespective of environment. ...