Krista R Kelly

SickKids, Toronto, Ontario, Canada

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Publications (9)8.62 Total impact

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    ABSTRACT: Stereotypical behaviors in captive polar bears (Ursus maritimus) can be detrimental to their welfare. These behaviors can be reduced through enrichment programs but are often not completely eliminated, so identifying potential triggers is important. The present study investigated the influences of seasonal changes, visitor density, and concurrent bear activity on stereotypical behaviors exhibited by 3 captive polar bears at the Toronto Zoo. All bears exhibited these behaviors; however, individual differences were found in duration and form. The male exhibited less stereotypical behavior during spring, and the females exhibited less stereotypical behavior during winter. An increase in visitor density was associated with more stereotypical behavior in 1 female but less stereotypical behavior in the other 2 bears. All bears engaged in more stereotypical behaviors when the other bears were inactive, and 1 female engaged in more stereotypical behaviors when the other bears were out of sight. Further, when conspecifics were active, all bears engaged in less stereotypical behaviors. Given the variability among individual bears, future enrichment programs must be tailored to the needs of individuals to maximize efficacy.
    Journal of applied animal welfare science : JAAWS. 06/2014;
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    ABSTRACT: Our objective was to measure how the misrouting of retinal ganglion cell (RGC) fibres affects the organization of the optic chiasm and lateral geniculate nuclei (LGN) in human albinism. We compared the chiasmal structures and the LGN in both pigmented controls and patients with albinism using high-resolution structural magnetic resonance imaging (MRI). We studied twelve patients with oculocutaneous albinism and twelve age-matched pigmented controls. Using a 3T MRI scanner, we acquired a T1 -weighted three-dimensional MPRAGE image of the whole brain, oriented so that the optic nerves, chiasm and tracts were in the same plane. We acquired multiple proton density-weighted images centered on the thalamus and midbrain, and averaged them to increase the signal, enabling precise manual tracing of the anatomical boundaries of the LGN. Albinism patients exhibited significantly smaller diameters of the optic nerves, chiasm and tracts, and optic chiasm and LGN volume compared with controls (ps < 0.001). The reductions in chiasmal diameters in the albinism compared with control group can be attributed to the abnormal crossing of optic fibres and the reduction of RGCs in the central retina. The volume of the LGN devoted to the center of the visual field may be reduced in albinism due to fewer RGCs representing the area where the fovea would normally lie. Our data may be clinically useful in addressing how genetic deficits compromise proper structural and functional development in the brain. J. Comp. Neurol., 2014. © 2014 Wiley Periodicals, Inc.
    The Journal of Comparative Neurology 02/2014; · 3.66 Impact Factor
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    ABSTRACT: Purpose Retinoblastoma is a rare eye cancer that generally occurs before 5 years of age and often results in enucleation (surgical removal) of the cancerous eye. In the present study, we sought to determine the consequences of early monocular enucleation on the morphological development of the anterior visual pathway including the optic chiasm and lateral geniculate nucleus. Methods A group of adults who had one eye enucleated early in life due to retinoblastoma was compared to binocularly intact controls. Although structural changes have previously been reported in late enucleation, we also collected data from one late enucleated participant to compare to our early enucleated participants. Measurements of the optic nerves, optic chiasm, optic tracts and lateral geniculate nuclei were evaluated from T1 weighted and proton density weighted images collected from each participant. Results The early monocular enucleation group exhibited overall degeneration of the anterior visual system compared to controls. Surprisingly, however, optic tract diameter and geniculate volume decreases were less severe contralateral to the remaining eye. Consistent with previous research, the late enucleated participant showed no asymmetry and significantly larger volume decreases in both geniculate nuclei compared to controls. Conclusions The novel finding of an asymmetry in morphology of the anterior visual system following long-term survival from early monocular enucleation indicates altered postnatal visual development. Possible mechanisms behind this altered development include recruitment of deafferented cells by crossing nasal fibres and/or geniculate cell retention via feedback from primary visual cortex. These data highlight the importance of balanced binocular input during postnatal maturation for typical anterior visual system morphology.
    NeuroImage: Clinical. 01/2014; 4:72–81.
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    ABSTRACT: Purpose. It is generally accepted that early visual deprivation from monocular enucleation (ME - surgical removal of one eye) results in intact spatial vision. Yet, motion perception studies in this population yield inconsistent findings. Here, we investigated speed and luminance contrast perception in a group of ME individuals. Methods. Twelve ME participants (mean age = 24 years; mean age at enucleation = 24 months) and 17 controls (mean age = 25 years) viewing binocularly (BV) and monocularly (MV) completed a series of speed discrimination and luminance contrast detection and discrimination tasks (VPixx technologies). Stimuli consisted of 0.5 cpd vertical sine wave gratings varying in speed (3.8 to 24°/s) or luminance contrast (0 to 78%). A second set of luminance contrast tasks with 4 cpd gratings teased apart any spatial frequency effects. Results. The ME group exhibited elevated speed discrimination thresholds compared to BV (P = 0.001) and MV (P = 0.027) controls, but intact luminance contrast discrimination (P = 0.530). Notably, both ME and MV groups displayed elevated luminance contrast detection thresholds compared to the BV group (Ps ≤ 0.006). However, the ME group exhibited slightly lower thresholds compared to MV controls for all 4 cps tasks. Conclusions. Our data indicate a disruption in the development of speed perception but not luminance contrast perception with monocular enucleation. These data highlight the importance of receiving normal binocular vision during postnatal development for the maturation of cortical regions associated with motion processing.
    Investigative ophthalmology & visual science 04/2013; · 3.43 Impact Factor
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    ABSTRACT: PURPOSE.: We investigated the effects of early monocular enucleation (ME) (surgical removal of one eye) on a high-level spatial visual ability, namely face perception. Early monocular deprivation of pattern vision from disorders such as strabismus, amblyopia, or cataract is associated with impairments in low-level spatial vision. This is inconsistent with studies of early ME that show either equivalent or enhanced low-level spatial vision compared with controls. Impairments on some aspects of face perception (i.e., feature-spacing and holistic face processing, both of which mature later in life) have been found with early pattern deprivation from congenital cataract. It is not clear whether the intact low-level spatial vision with ME will also persist with high-level face perception or whether deficits similar to those found with cataract will emerge. METHODS.: We tested individuals who have experienced early ME and controls on a series of high-level spatial visual tasks that measure feature-spacing, feature, and holistic face processing. RESULTS.: The ME group were slower for feature spacing and feature tasks. Furthermore, the ME group did not exhibit the normal pattern of poorer performance on the aligned compared with misaligned composite face discrimination tasks, demonstrating a lack of the composite face effect. However, they did show the normal pattern of poorer performance on same vs. different trials on the aligned tasks. CONCLUSIONS.: These results indicate an impairment in the feature spacing and feature aspects of face perception with ME. They also suggest a present yet, incomplete, development of holistic face processing in this group. Although the complete removal of inhibitory binocular interactions and/or the absence of binocular competition in early ME may result in cortical reorganization of the visual system and preserve low- to mid-level spatial vision, it may be insufficient for the maturation of high-level face perception.
    Optometry and vision science: official publication of the American Academy of Optometry 12/2011; · 1.53 Impact Factor
  • K. Kelly, J. Steeves
    Journal of Vision - J VISION. 01/2010; 8(6):188-188.
  • Journal of Vision - J VISION. 01/2010; 10(7):455-455.
  • Journal of Vision - J VISION. 01/2010; 9(8):673-673.
  • C. Mullin, K. Kelly, J. Steeves
    Journal of Vision - J VISION. 01/2010; 9(8):117-117.