(10%) and binaural cells (90%) exist in the MGN. The monaural cells are primarily responsive to sound in the contralateral hemifield. Binaural cells are typically similar to the EE or EI type found in the IC. Definitions of abbreviations IC = Inferior colliculus EE (Excitatory excitatory) type neurons are characterized by excitatory responses to monaural stimulations of both ears. This response may either be higher than the monaural response (EE– facilitation) Or lower (EE– occlusion) EI (Excitatory inhibitory) type neurons Are characterized by monaural excitation (usually from the contralateral ear). The ipsilateral neuron is inhibited when contralateral ear is stimulated at the same time Dorsal subnucleus Cell types There are a large number of cell types present in the dorsal subnucleus of the medial geniculate body (DMGN): At least two principal cell types have been found, along with two distinct types of interneurons. Several sub-nuclei have been identified based on morphology. No frequency-specific layering has been found in the DMGN. Function Many types of responses are present in the DMGB that appear to vary by sub-nuclei. Generally, the responses are broadly tuned, but some cells appear to respond only to complex stimuli. Other cells are multi modal, often responding to somatosensory as well as auditory stimuli. Medial subnucleus Cell types Cells in the medial subnucleus of the medial geniculate body (MMGN) have large irregular shaped dendritic trees. There is no clear segregation based on the source of these inputs. Function The MMGN seems to functionally be responsible for detection of the relative intensity and duration of a sound. It shows a wide range of responses to auditory stimuli. Binaural interactions found in the MMGN include EE, EI, and IE types. Both broadly and narrowly tuned cells have been observed. A type of intensity tuning has also been observed. In this type of cell, the response actually decreases as sound intensity increases above a specific level. Almost all cells in the MMGN appear to respond for the duration of the stimulus, and have very little adaptation. Individual cells still appear to be preferentially tuned to certain frequencies, but they often have more than one and are broadly tuned within these cell frequencies. It is not clear whether there truly is one, none, or many tonotopic organizations maps present in the MMGN. Anaesthetics tend to have large effects on cells within the MMGN, making responses difficult to study. Finally, the behaviour of