Amyotrophic Lateral Sclerosis/physiopathology; Brain/physiopathology; Motor Neuron Disease/physiopathology; Superoxide Dismutase/genetics; Amyotrophic Lateral Sclerosis/genetics; Amyotrophic Lateral Sclerosis/pathology; Analysis of Variance; Animals; Brain/metabolism; Brain/pathology; Disease Models, Animal; Humans; Magnetic Resonance Imaging/methods; Male; Mice; Mice, Inbred Strains; Mice, Transgenic; Motor Cortex/metabolism; Motor Cortex/pathology; Motor Cortex/physiopathology; Motor Neuron Disease/genetics; Motor Neuron Disease/pathology; Motor Neurons/metabolism; Motor Neurons/pathology; Mutation, Missense/genetics; Nerve Degeneration/genetics; Nerve Degeneration/pathology; Nerve Degeneration/physiopathology; Spinal Cord/metabolism; Spinal Cord/pathology; Spinal Cord/physiopathology; Superoxide Dismutase/metabolism; Thalamus/metabolism; Thalamus/pathology; Thalamus/physiopathology; Trigeminal Nuclei/metabolism; Trigeminal Nuclei/pathology; Trigeminal Nuclei/physiopathology