Neuron
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Theories of empathy differ regarding the relative contributions of automatic resonance and perspective taking in understanding others' emotions. Patients with the rare syndrome of congenital insensitivity to pain cannot rely on "mirror matching" (i.e., resonance) mechanisms to understand the pain of others. ⋯ In these patients (but not in healthy controls), empathy trait predicted ventromedial prefrontal responses to somatosensory representations of others' pain and posterior cingulate responses to emotional representations of others' pain. These findings underline the major role of midline structures in emotional perspective taking and understanding someone else's feeling despite the lack of any previous personal experience of it--an empathic challenge frequently raised during human social interactions.
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Radial glia are highly polarized cells that serve as neuronal progenitors and as scaffolds for neuronal migration during construction of the cerebral cortex. How radial glial cells establish and maintain their morphological polarity is unknown. Using conditional gene targeting in mice, we demonstrate that adenomatous polyposis coli (APC) serves an essential function in the maintenance of polarized radial glial scaffold during brain development. ⋯ Elimination of APC further leads to marked instability of the radial glial microtubule cytoskeleton. The resultant changes in radial glial function and loss of APC in radial glial progeny lead to defective generation and migration of cortical neurons, severely disrupted cortical layer formation, and aberrant axonal tract development. Thus, APC is an essential regulator of radial glial polarity and is critical for the construction of cerebral cortex in mammals.