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.
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The central nervous system is plastic throughout life, but is most sensitive to the statistics of the sensory environment during critical periods of early postnatal development. In the auditory cortex, various forms of acoustic experience have been found to shape the formation of receptive fields and influence the overall rate of cortical organization. ⋯ Cortical inhibition is poorly tuned in the infant brain, but becomes co-tuned with excitation in an experience-dependent manner over the first postnatal month. We discuss evidence suggesting that this may be a general feature of the developing cortex, and describe the functional implications of such transient excitatory-inhibitory imbalance.
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Neurosci Biobehav Rev · Oct 2011
ReviewDrug-sensitive reward in crayfish: an invertebrate model system for the study of SEEKING, reward, addiction, and withdrawal.
In mammals, rewarding properties of drugs depend on their capacity to activate appetitive motivational states. With the underlying mechanisms strongly conserved in evolution, invertebrates have recently emerged as a powerful new model in addiction research. In crayfish natural reward has proven surprisingly sensitive to human drugs of abuse, opening an unlikely avenue of research into the basic biological mechanisms of drug addiction. ⋯ This work demonstrates that crayfish offer a comparative and complementary approach in addiction research. Serving as an invertebrate animal model for the exposure to mammalian drugs of abuse, modularly organized and experimentally accessible nervous systems render crayfish uniquely suited for studying (1) the basic biological mechanisms of drug effects, (2) to explore how the appetitive/seeking disposition is implemented in a simple neural system, and (3) how such a disposition is related to the rewarding action of drugs of abuse. This work aimed to contribute an evolutionary, comparative context to our understanding of a key component in learning, and of natural reward as an important life-sustaining process.
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Neurosci Biobehav Rev · Oct 2011
ReviewEmotional foundations of music as a non-pharmacological pain management tool in modern medicine.
This paper reviews the use of music as an adjuvant to the control of pain, especially in medical procedures. Surgery causes stress and anxiety that exacerbates the experience of pain. Self-report of and physiological measures on post-surgical patients indicate that music therapy or music stimulation reduces the perception of pain, both alone and when part of a multimodal pain management program, and can reduce the need for pharmaceutical interventions. ⋯ As summarized, we currently know that musical pieces chosen by the patient are commonly, but not always, more effective than pieces chosen by another person. Further research should focus both on finding the specific indications and contra-indications of music therapy and on the biological and neurological pathways responsible for those findings (related evidence has implicated brain opioid and oxytocin mechanisms in affective changes evoked by music). In turn, these findings will allow medical investigators and practitioners to design guidelines and reliable, standardized applications for this promising method of pain management in modern medicine.