Dissertation > Excellent graduate degree dissertation topics show

Effects of Aging on the Spatial Frequency Selectivity of Visual Cortical Neurons and Activities of Glial Cells

Author: ChangZuo
Tutor: HuaTianMiao
School: Anhui Normal University
Course: Neurobiology
Keywords: cat senescence visual cortex spatial frequency selectivity astrocytes
CLC: Q42
Type: Master's thesis
Year: 2010
Downloads: 7
Quote: 0
Read: Download Dissertation

Abstract


Our ability to discriminate fine morphological difference between objects, called visual acuity, decreases during aging. It’s unclear if this visual acuity decrease relates to selectivity changes of visual cortical neurons to visual stimulus spatial frequencies. On the other hand, previous investigations on aged visual cortex show that functional degradation of visual cortical neurons are accompanied by a decreased expression of neurotransmitters, especially inhibitory ones. However, there is no study to report whether functional decline of visual cortical neurons is directly correlated with activity changes of glial cells. This research uses cats as subjects and investigate the selectivity change of V1 neurons to visual stimulus spatial frequencies with age as well as the impact of senescence on glial cells activity changes, trying to uncover the neural mechanisms that may underlie the reduced visual acuity and other visual ability declines in the aged individuals. The main results are as follows:1. We recorded respectively the tuning response of V1 neurons in both old and young adult cats to varied stimulus spatial frequencies using in vivo extracellular single-unit recording techniques. Our statistical analysis showed that the mean optimal spatial frequency value of visual stimuli that evoked the maximal response of V1 neurons in old cats was significantly lower than that in young adult cats. This result is consistent with that reported in the V1 of old monkeys, suggesting that age-related functional declines of visual cortical cells might be an important neural base mediating visual acuity reduction in senescent individuals.2. We comparatively observed the activity of GFAP-immunoreactive (GFAP-IR) astrocytes in the primary visual cortex of both old and young adult cats using general immunohistochemistry method. Our results showed that the mean density of GFAP-IR cells in each cortical layer and the white matter of V1 in old cats were significantly higher than in young adult cats (p<0.001). Compared with young adult cats, the mean diameter of astrocytes in both gray matter and white matter of old cats was significantly increased (p<0.0001). Further, GFAP immunoreaction intensity in the primary visual cortex of old cats was stronger than that of young adult ones. These results suggest that The functional degradation of neurons in the visual cortex of old cats is accompanied by an improved activity of astrocytes, which could be beneficial to communication between neurons and thus may compensate neuronal function declines during senescence.

Related Dissertations

  1. Studies on Senescence Difference in Roots and Leaves in Two Varieties of Maize and Their Regulator,S513
  2. Effects of Nitrogen Management Practices on Expression and Degradation of Bt-protein in Transgenic Cotton,S562
  3. Heme Oxygenase is Involved in Cytokinin-Induced Alleviation of Senescence Induced by Darkness in Detached Wheat Leaves,S512.1
  4. Study on Clinical Anesthesia for Shumianning, A New Compound Anesthetic in Cats,S858.293
  5. The Experimental Research on Using Electroacupuncture to Treat the Dysfunction Memory of Rats Suffered from Alzheimer’s Disease,R245
  6. Analysis of Morphological Appearances and Physiologal Characteristics in Old Camphor Trees Having Different Growth Potentials,S792.23
  7. The Effects of Trophic Effects of Bone Marrow Mesenchymal Stem Cells on Astrocytes Induced by Carbon Monoxide in Culture,R329
  8. Morphological Characteristics of Astrocytes in EAN–a Tricellular System for Study on Neuroprotection and Neuroregeneration,R651.1
  9. Aging Affects Response Latency and Variability of Cells in Different Visual Areas in Cats,Q436
  10. Research & Implementation of Computerized Adaptive Testing System,TP311.52
  11. Effect of NGF on the Binocular Fusion of Cats,R77
  12. The Expression of CyclinA、CyclinD1 and P27 in Different Situations of Astrocytes,R329
  13. Protective Role of Sonic Hedgehog Signaling in Primary Cultured Cortical Astrocytes Against Oxidative Stress,R741
  14. Aspirin-triggered Lipoxin Inhibit the Inflammatory Response Induced by Lipopolysaccharide in Primary Astrocytes,R965
  15. Effects of Aspirin-Triggered Lipoxin on the Interleukin -6 Induced Inflammatory Response in Astrocytes,R965
  16. Binocular form deprivation of adult rat visual cortex plasticity and CSPGs and the relationship between the expression of tPA,R77
  17. \,I712.074
  18. Based on Voronoi diagram of image information hiding method,TP309
  19. Design of Visual Experimental Platform Based on Optical Imaging and Microelectrode Array,TP391.41
  20. Astrocytes in the study of the role of the adult mouse brain angiogenesis process,R743
  21. 100 Cases of COPD Patients with CAT Score Correlation with MMRC Score,R563.9

CLC: > Biological Sciences > Physiology > Neurophysiology
© 2012 www.DissertationTopic.Net  Mobile