Models of subcortical functions in language: Current status

Recent models of subcortical functions in language are discussed. Some emphasis is placed upon whether the thalamus and basal ganglia function via neuroregulation or direct information processing, or perhaps they play no role at all in language. Regarding the basal ganglia, models vary from suggesting no functional significance for language, to hypothesizing a role in the release of cortically formulated segments into the speech output stream, to theorizing a pivotal part in the monitoring and selection of lexical alternatives. For the thalamus, suggested roles include participating with the basal ganglia in selection of lexical alternatives or release of formulated responses, semantic monitoring, or selective engagement of cortical areas necessary for different language processes. In general, theorists agree the thalamus plays some fundamental or supportive role in language, though no consensus has been reached about the nature of this role. It is less clear that the basal ganglia participate in primary or supportive functions for language. The importance of subcortical functions for understanding how brain systems produce language and cognition is noted. (C) 1997 Elsevier Science Ltd. All rights reserved.