Biology subjects

Whitney, D. E.

Publications and source records attributed to Whitney, D. E..

3 recordsLinked to original sources

bioRxiv2022

Experience drives the development of novel, reliable cortical sensory representations from endogenously structured networks

The fundamental structure of cortical networks arises early in development prior to the onset of sensory experience. However, how endogenously generated networks respond to the onset of sensory experience, and how they form mature sensory representations with experience remains unclear. Here we examine this nature-nurture transform using in vivo calcium imaging in ferret visual cortex. At eye-opening, visual stimulation evokes robust patterns of cortical activity that are highly variable within and across trials, severely limiting stimulus discriminability. Initial evoked responses are distinct from spontaneous activity of the endogenous network. Visual experience drives the development of low-dimensional, reliable representations aligned with spontaneous activity. A computational model shows that alignment of novel visual inputs and recurrent cortical networks can account for the emergence of reliable visual representations. One sentence summaryThe reliability of cortical representations emerges from experience-driven reorganization of endogenous networks

neuroscience↗

bioRxiv2019

Experience-dependent reorganization drives the development of a binocularly unified representation of orientation in ferret visual cortex

Across sensory areas, neural microcircuits consolidate diverse streams of information into unified, representations of the external world. In the carnivore visual cortex, where eye-specific inputs converge, it has been posited that a single, shared columnar representation of orientation develops independent of sensory experience. In this study, in vivo calcium imaging with columnar and cellular resolution reveals a strikingly different developmental process in ferret visual cortex, starting with an early developmental period in which contralateral, ipsilateral or binocular stimulation each yield distinct well-organized representations of orientation that are misaligned at the columnar and cellular scale. Experience-dependent processes drive the reorganization of these three representations towards a single binocularly-aligned representation resembling the early binocular representation through concerted shifts in the preferred orientation of individual neurons. Thus, contrary to previous findings, a unified binocular representation of orientation results from an experience-dependent process that aligns the activity patterns of three distinct neural representations.

neuroscience↗

bioRxiv2018

Long-range order from local interactions: organization and development of distributed corticalnetworks

The cortical networks that underlie behavior exhibit an orderly functional organization at local and global scales, which is readily evident in the visual cortex of carnivores and primates1-6. Here, neighboring columns of neurons represent the full range of stimulus orientations and contribute to distributed networks spanning several millimeters2,7-11. However, the principles governing functional interactions that bridge this fine-scale functional architecture and distant network elements are unclear, and the emergence of these network interactions during development remains unexplored. Here, by using in vivo wide-field and 2-photon calcium imaging of spontaneous activity patterns in mature ferret visual cortex, we find widespread and specific modular correlation patterns that accurately predict the local structure of visually-evoked orientation columns from the spontaneous activity of neurons that lie several millimeters away. The large-scale networks revealed by correlated spontaneous activity show abrupt fractures in continuity that are in tight register with evoked orientation pinwheels. Chronic in vivo imaging demonstrates that these large-scale modular correlation patterns and fractures are already present at early stages of cortical development and predictive of the mature network structure. Silencing feed-forward drive through either retinal or thalamic blockade does not affect network structure suggesting a cortical origin for this large-scale correlated activity, despite the immaturity of long-range horizontal network connections in the early cortex. Using a circuit model containing only local connections, we demonstrate that such a circuit is sufficient to generate large-scale correlated activity, while also producing correlated networks showing strong fractures, a reduced dimensionality, and an elongated local correlation structure, all in close agreement with our empirical data. These results demonstrate the precise local and global organization of cortical networks revealed through correlated spontaneous activity and suggest that local connections in early cortical circuits may generate structured long-range network correlations that underlie the subsequent formation of visually-evoked distributed functional networks.

neuroscience↗