Fibers from the magnocellular nucleus had relatively few terminal branches but innervated extremely wide areas by collaterals of single axons. Two types of axons arose from the magnocellular nucleus, one terminating preferentially in middle cortical layers and the other exclusively in layer I. These may arise respectively from parvalbumin- and calbindin-immunoreactive cell populations in the magnocellular nucleus.. 
The magnocellular nucleus contains domains of parvalbumin and calbindin cells. Those in anterodorsal and posterodorsal nuclei project to surrounding auditory fields with less dense parvalbumin immunoreactivity; those in the magnocellular nucleus project widely to auditory and other fields. Injections of middle cortical layers label a large majority of parvalbumin cells in the ventral, anterodorsal, or posterodorsal nuclei and in the magnocellular nucleus.
The magnocellular nucleus of the medial geniculate body (MGm) develops physiological plasticity during classical conditioning and may be involved in learning-induced receptive field plasticity in the auditory cortex.
The topography and cellular typology of the mediorostral nucleus suggest its homology with the so-called magnocellular nucleus of other mammals, an identity that was previously assigned to the internal nucleus.
Retrograde cell labeling occurred in centers giving rise to ascending systems of diffuse projections: locus coeruleus (LC), dorsal raphe nucleus (DR), and basal magnocellular nucleus (B).
A second, weaker projection to field A originates in a magnocellular nucleus that is situated caudomedially in the MG and was therefore named the caudomedial nucleus.
Where layers V and VI become subdivided in the homotypical cortex, the auditory and adjacent fields were only observed in cases in which the magnocellular nucleus of the medial geniculate body was involved by the injection of isotope.
of Darkschewitz receives both ipsilateral and crossed input; the magnocellular nucleus of the medial geniculate body receives a small contribution which is mainly ipsilateral.
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