Biology subjects

Krubitzer, L. A.

Publications and source records attributed to Krubitzer, L. A..

5 recordsLinked to original sources

bioRxiv2026

The contribution of cross-modal sensory input to reaching and grasping in blind and sighted short-tailed opossums

Reaching and grasping are essential goal-directed behaviors that require the integration of visual, olfactory, and somatosensory inputs. Although the loss of vision can profoundly disrupt sensory-guided behaviors, mammals often exhibit compensatory cross-modal plasticity allowing them to reach and grasp with ease. To examine how early sensory loss shapes reaching behavior, we performed bilateral enucleations in short-tailed opossums (Monodelphis domestica) of either sex at postnatal day 4, before retino-thalamic and thalamocortical connections have formed. We assessed performance in early blind (EB) and sighted control (SC) animals using a semi-naturalistic reach-to-grasp task requiring precise unilateral limb targeting to retrieve a dead cricket. To isolate the contributions of specific sensory modalities to this task, we selectively disrupted olfactory and mystacial vibrissae inputs and manipulated lighting conditions during task performance. EB opossums were capable of accurate reaching and grasping and showed no significant differences in performance relative to SC animals. Both groups relied strongly on tactile input, as whisker trimming significantly increased targeting error. Removal of olfactory input also impaired performance, with a disproportionately greater effect in EB animals. These findings show that short-tailed opossums retain functional reach-to-grasp behavior after early vision loss and that accurate forelimb movements arise from enhanced spared sensory systems.

neuroscience↗

bioRxiv2025

Complex three-dimensional rearing environments amplify compensatory plasticity following early blindness

The neocortex has a remarkable capacity to alter its functional organization and connectivity in response to sensory loss, particularly if this loss occurs early in life. A key question is whether this cross-modal reorganization is driven by sensory deprivation or by enhanced use of the spared senses. We investigated how different rearing environments shape neural responses in primary somatosensory cortex (S1) of short-tailed opossums (Monodelphis domestica), following elimination of visual inputs through bilateral enucleation in early development. Early blind and sighted littermates were reared in enriched environments to promote active tactile exploration in three-dimensional (3D) space, or in standard laboratory cages. In adulthood, both enriched groups showed adaptive changes in exploration patterns and gap crossing behaviors relative to standard-reared counterparts. Thus, early blind animals showed behavioral compensation when challenged by complex environments. Enriched rearing increased selectivity of S1 neural responses to whisker touch and altered receptive field shapes such that they were less horizontally anisotropic. This shift was strongest in enriched early blind animals, enhancing tuning along the behaviorally relevant horizontal axis more than in standard-reared early blind animals. Thus, alterations in receptive fields of neurons in S1 following early blindness were amplified by environmental complexity. Sighted opossums reared with enrichment also showed similar whisker receptive field plasticity, though to a slightly lower degree. Together, these results demonstrate the strong influence of the rearing environment on reorganization of cortex that processes inputs from the spared senses, underscoring the role of experience in directing compensatory plasticity following early sensory loss. SIGNIFICANCE STATEMENTEnhanced perceptual abilities following early sensory loss are often attributed to cross-modal recruitment of cortex linked to the deprived sense. However, plasticity also occurs within cortical areas representing spared modalities. It remains unresolved whether deprivation alone is sufficient to induce such reorganization, or whether experience using the spared sense is required. We show that enriched rearing amplifies neural coding changes in primary somatosensory cortex after early blindness, shaping receptive field geometry and promoting adaptive behavioral strategies aligned with environmental demands. Comparable changes in sighted animals reared under the same conditions reveal that reliance on touch--rather than visual deprivation alone--drives this neural and behavioral plasticity, supporting the critical role of experience in enhancing functional outcomes after early sensory impairment.

neuroscience↗

bioRxiv2020

Developmental plasticity of texture discrimination following early vision loss in the marsupial Monodelphis domestica

Behavioral strategies that depend on sensory information are not immutable; rather they can be shaped by the specific sensory context in which animals develop. This behavioral plasticity depends on the remarkable capacity for the brain to reorganize in response to alterations in the sensory environment, particularly when changes in sensory input occur at an early age. To study this phenomenon, we utilize the short-tailed opossum, a marsupial that has been a valuable animal model to study developmental plasticity due to the extremely immature state of its nervous system at birth. Previous studies in opossums have demonstrated that removal of retinal inputs early in development results in profound alterations to cortical connectivity and functional organization of visual and somatosensory cortex; however, behavioral consequences of this plasticity are not well understood. We trained early blind (EB) and sighted control (SC) opossums to perform a two-alternative forced choice texture discrimination task. Whisker trimming caused an acute deficit in discrimination accuracy for both EB and SC animals indicating that they primarily used a whisker-based strategy to guide choices based on tactile cues - though performance recovered in days, suggesting a shift to the use of other body parts when whiskers were absent. Mystacial whiskers were important for performance in both groups; however, genal whiskers only contributed to performance in EB animals. EB opossums significantly outperformed SC opossums in discrimination accuracy, being more sensitive to textural differences by ~75 m smaller. Our results support behavioral compensation following early blindness using tactile inputs, especially the whisker system.

neuroscience↗

bioRxiv2020

Performance and behavioral flexibility on a complex motor task depend on available sensory inputs in early blind and sighted short-tailed opossums.

The early loss of vision results in a reorganized visual cortex that processes tactile and auditory inputs. Recent studies in the short-tailed opossum (Monodelphis domestica) found that the connections and response properties of neurons in somatosensory cortex of early blind animals are also altered. While research in humans and other mammals shows that early vision loss leads to heightened abilities on discrimination tasks involving the spared senses, if and how this superior discrimination leads to adaptive sensorimotor behavior has yet to be determined. Moreover, little is known about the extent to which blind animals rely on the spared senses. Here, we tested early blind opossums on a sensorimotor task involving somatosensation and found that they had increased limb placement accuracy. However, increased reliance on tactile inputs in early blind animals resulted in greater deficits in limb placement and behavioral flexibility when the whiskers were trimmed.

neuroscience↗

bioRxiv2019

Modelling the emergence of whisker barrels

Brain development relies on an interplay between genetic specification and self-organization. Striking examples of this relationship can be found in the somatosensory brainstem, thalamus, and cortex of rats and mice, where the arrangement of the facial whiskers is preserved in the arrangement of cell aggregates to form precise somatotopic maps. We show in simulation how realistic whisker maps can self-organize, by assuming that information is exchanged between adjacent cells only, under the guidance of gene expression gradients. The resulting model provides a simple account of how patterns of gene expression can constrain spontaneous pattern formation to faithfully reproduce functional maps in subsequent brain structures.

developmental biology↗