emotions is especially hard since emotions are complex and can lead to subjective response. Since the majority of experiments in emotional lateralization have been on fear this leaves the question of whether other emotions are also lateralized. Below are two major issues associated with many of the experiments studying emotion that require further explanation. Sample size A large percent of the human studies are of anomalies due to accidents, tumors, or attempts to cure disease (e.g. seizures) using lesioning. Since very few such cases exist the sample size of human studies of emotional lateralization are generally very limited and may be as small as single person. While these studies may provide a good insight into certain brain regions and their functions their conclusions are not definite. Animal studies may help in understanding this problem but emotions in humans are generally considered more complicated than in most animals. Functional imaging There are several limitations when using fMRI or PET to study emotional responses. Because fMRI measures changes in blood oxygenation, using the BOLD effect, its temporal resolution is limited by the haemodynamic response to several seconds. PET has similar limits, offering slightly better temporal resolution and slightly worse spatial resolution. Lesioning Lesions rarely are localized and can affect large areas of the brain. Processing in the brain is generally not localized and requires many areas of the brain to process. Furthermore, lesioning may interfere with pathways that span the lesion site. Thus, lesions are not always a good way to determine what specific brain areas do. Therefore, a degree of skepticism should be kept in mind when viewing lateralization data from lesion studies. Notes References Neuropsychology Emotion