Unimodal and cross-modal plasticity in the ‘deaf’ auditory cortex

Congenital auditory deprivation leads to deficits in the auditory cortex. The present review focuses on central aspects of auditory deprivation: development, plasticity, corticocortical interactions, and cross-modal reorganization. We compile imaging data from human subjects, electroencephalographic data from cochlear implanted children, and animal research on congenital deafness. Behavioral, electroencephalographic, and imaging data in humans correspond well to data behavioral and neurophysiological data obtained from congenitally deaf cats. The available data indicate that auditory deprivation leads to 'decoupling' of the primary auditory cortex from cognitive modulation of higher-order auditory areas. Higher-order auditory areas undergo a strong cross-modal reorganization and take-over new functions. Due to these and other deficits of intrinsic microcircuitry, the cortical column can not integrate bottom-up and top-down influences in deaf auditory cortex. In the ultimate consequence perceptual learning is compromised, resulting in sensitive periods.

Neuroscience and psychopharmacology into the next millennium

The end of the millennium provides an opportunity to review some of the common practices that were present in psychopharmacology during the 20th century. The author focuses on two approaches that have dominated research and guided the clinical application of psychopharmacologic therapeutics: the unitary clinically-based and single-lesion perspectives. The author expands upon these older formulations of neuropsychiatric disease pathogenesis and describes how the approach to psychopharmacologic research and therapeutics has changed in light of advances in the basic neurosciences. Relevant recent advances in the basic neurosciences that shed light on the pathophysiology of neuropsychiatric disease states and that guide psychopharmacologic practices are described. The use of atypical antipsychotic agents to treat schizophrenia is given as one example of the clinical applications of the approach to psychopharmacology in the next century.