Potential for change: Characterizing synaptic plasticity following visual discrimination learning in adult rats.

ii Co-Authorship . iii Acknowledgements . v List of Figures . x List of Abbreviations . xii Chapter 1 General Introduction . 1 1.1 Experience-dependent synaptic plasticity and the synaptic plasticity memory hypothesis . 1 1.2 LTP and LTD as synaptic mechanisms of experience-dependent plasticity . 2 1.3 Adult rat visual system as a model system . 4 1.4 Visual perception in the rat . 6 1.5 Experience-dependent plasticity in the adult visual system . 7 1.6 Concluding remarks . 9 1.7 Objectives . 9 Chapter 2 Design of a noninvasive face-mask for ocular occlusion in rats and assessment in a visual discrimination paradigm . 12 2.1 Abstract . 12 2.2 Introduction . 13 2.3 Materials and methods . 14 2.3.1 Subjects . 14 2.3.2 Harness and face-mask construction . 15 2.3.3 Visual discrimination performance under monocular viewing conditions . 17 2.3.4 Probe trial test of interocular transfer . 18 2.3.5 Data analysis . 18 2.4 Results . 19 2.4.1 Task acquisition . 19 2.4.2 Test of interocular transfer . 20 2.5 Discussion . 22 Chapter 3 Metaplastic up-regulation of LTP in rat visual cortex by monocular visual training: Requirement of task mastery, hemispheric specificity, and NMDA-NR2B involvement.24 3.1 Abstract . 24 3.2 Introduction . 26 3.3 Methods . 28 vii 3.3.1 Subjects . 28 3.3.2 Monocular visual discrimination training . 29 3.3.3 Surgical Preparation . 29 3.3.4 Input output curves and paired pulse facilitation . 30 3.3.5 Pharmacology . 31 3.3. 6 Data analysis . 32 3.4 Results . 34 3.4.1 Monocular visual discrimination acquisition . 34 3.4.2 Probe trial test of interocular transfer . 35 3.4.3 Effect of visual training on input-output curves . 37 3.4.4 Effect of visual training on paired-pulse facilitation . 39 3.4.5 Effect of monocular visual discrimination training on LTP . 41 3.4. 6 Hemisphere-specific potentiation mediated by NR2B subunits of NMDA receptors . 45 3.4. 7 Effect of TBS on short-term plasticity assessed by PPF . 46 3.5 Discussion . 47 Chapter 4 Assessment of different induction protocols to elicit long-term depression (LTD) in the rat visual cortex in vivo. 55 4.1 Abstract . 55 4.2 Introduction . 56 4.3 Experimental Procedures . 58 4.3.1 Subjects . 58 4.3.2 Surgical preparation . 58 4.3.3 Electrophysiology . 59 4.3.4 Data collection and drug application . 60 4.3.5 Data analysis . 61 4.4 Results . 62 4.4.1 Effects of LFS on field postsynaptic potentials (fPSPs) in V1 . 62 4.4.2 Effects of different anesthetics on SLF-induced depression. 66 4.4.3 Effects of blockade of N-methyl-D-aspartate or metabotropic glutamate receptors on depression following SLFS . 67 4.5 Discussion . 70 Chapter 5 Visual discrimination training does not elicit LTD in the primary visual cortex or perirhinal cortex of adult rats . 76 5.1 Abstract . 76 viii 5.2 Introduction . 77 5.3 Materials and Methods . 80 5.3.1 Subjects . 80 5.3.2 Y-maze visual discrimination apparatus . 81 5.3.3 Visual cues . 82 5.3.4 Visual discrimination training . 83 5.3.5 Surgical preparation . 84 5.3. 6 Electrophysiology . 85 5.3. 7 Data collection . 86 5.3. 8 Data analysis . 87 5.4 Results . 88 5.4.1 Visual discrimination acquisition .