Neuroscience and biobehavioral reviews
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Neurosci Biobehav Rev · Jan 2012
Meta AnalysisBrain regions with mirror properties: a meta-analysis of 125 human fMRI studies.
Mirror neurons in macaque area F5 fire when an animal performs an action, such as a mouth or limb movement, and also when the animal passively observes an identical or similar action performed by another individual. Brain-imaging studies in humans conducted over the last 20 years have repeatedly attempted to reveal analogous brain regions with mirror properties in humans, with broad and often speculative claims about their functional significance across a range of cognitive domains, from language to social cognition. Despite such concerted efforts, the likely neural substrates of these mirror regions have remained controversial, and indeed the very existence of a distinct subcategory of human neurons with mirroring properties has been questioned. ⋯ The analysis revealed 14 separate clusters in which activation has been consistently attributed to brain regions with mirror properties, encompassing 9 different Brodmann areas. These clusters were located in areas purported to show mirroring properties in the macaque, such as the inferior parietal lobule, inferior frontal gyrus and the adjacent ventral premotor cortex, but surprisingly also in regions such as the primary visual cortex, cerebellum and parts of the limbic system. Our findings suggest a core network of human brain regions that possess mirror properties associated with action observation and execution, with additional areas recruited during tasks that engage non-motor functions, such as auditory, somatosensory and affective components.
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Working memory is a dynamic neural system for temporarily maintaining and processing information. The prefrontal cortex (PFC) plays an important role in working memory. However, several evidences indicate that the thalamic mediodorsal nucleus (MD) also participates in working memory. ⋯ Most MD neurons with delay activity represented information regarding motor responses, whereas some represented information regarding visual cues, suggesting that the MD participates more in prospective aspects of working memory, in contrast to the PFC, in which a minority participates in prospective aspects of working memory. A population vector analysis revealed that the transformation of sensory-to-motor information occurred during the earlier phase of the delay period in the MD compared with the PFC. These results indicate that reverberating neural circuits constructed by reciprocal connections between the MD and the PFC could be an important component for constructing prospective information in the PFC.