Trends in neurosciences
-
Trends in neurosciences · Sep 1994
ReviewMagnetoencephalography in studies of human cognitive brain function.
Magnetoencephalography provides a new dimension to the functional imaging of the brain. The cerebral magnetic fields recorded noninvasively enable the accurate determination of locations of cerebral activity with an uncompromized time resolution. ⋯ Therefore, attempts are being made to combine magnetoencephalography with other brain-imaging methods to improve spatial localization of multiple sources and, simultaneously, to achieve a more complete characterization of different aspects of brain activity during cognitive processing. Owing to its good time resolution and considerably better spatial accuracy than that provided by EEG, magnetoencephalography holds great promise as a tool for revealing information-processing sequences of the human brain.
-
Trends in neurosciences · Mar 1992
ReviewActivity-dependent neuronal plasticity following tissue injury and inflammation.
Increases in neuronal activity in response to tissue injury lead to changes in gene expression and prolonged changes in the nervous system. These functional changes appear to contribute to the hyperalgesia and spontaneous pain associated with tissue injury. This activity-dependent plasticity involves neuropeptides, such as dynorphin, substance P and calcitonin gene-related peptide, and excitatory amino acids, such as NMDA, which are chemical mediators involved in nociceptive processing. ⋯ Dynorphin applied to the spinal cord also induces an enlargement of receptive fields. NMDA antagonists block the hyperexcitability produced by inflammation. A model has been proposed in which dynorphin, substance P and calcitonin gene-related peptide enhance excitability at NMDA receptor sites, leading first to dorsal horn hyperexcitability and then to excessive depolarization and excitotoxicity.