Cerebral microhemorrhages (CMBs) are small hemorrhagic strokes found in the brain, also known as silent stroke since they do not illicit noticeable symptoms. Recently, due to the development of various imaging modalities and aging population in the western world, increasing number of CMBs are detected. Clinical studies have shown that aging and hypertension significantly increases the chance of such bleeds and the National Institute of Health recognizes CMBs as a major factor in Alzheimer disease pathology. Independent events of CMBs are also a risk factor for subsequent larger intracerebral hemorrhages, ischemic stroke, Binswager’s disease and Alzheimer’s disease. However, studies in cellular level are lacking, partially due to inadequate animal model that allow both detection and follow up analysis of such small bleeds. We used tightly focused femtosecond laser pulses to injure single penetrating arterioles in the cortex of live anesthetized rodents and used multi-photon excited fluorescence imaging to quantify inflammatory responses over long periods of time. The work presented in this dissertation provides comprehensive spatial and temporal pathological consequences after micro scale hemorrhagic injury to a single blood vessel in the brain.