Impaired pain in mice lacking first-order posterior medial thalamic neurons.

The thalamus plays an important role in sensory and motor information processing by mediating communication between the periphery and the cerebral cortex. Alterations in thalamic development have profound consequences on sensory and motor function. In this study, we investigated a mouse model in which thalamic nuclei formation is disrupted because of the absence of Sonic hedgehog ( Shh ) expression from 2 key signaling centers that are required for embryonic forebrain development.

Three- to four-year-olds' recognition that symbols have a stable meaning: pictures are understood before written words.

In 4 experiments 120 three- to four-year-old nonreaders were asked the identity of a symbolic representation as it appeared with different objects. Consistent with Bialystok (2000), many children judged the identity of written words to vary according to the object with which they appeared but few made such errors with recognizable pictures. Children also made few errors when the symbols were unrecognizable pictures.