Auditory Brain Atlas

Adult Cat (histochemistry and IHC)

Histochemical and immunohistochemical assays of auditory and multisensory areas in the cat (cortex, thalamus)
The images in this section were obtained in collaboration with the laboratory of Dr. Mark Wallace.

The cat has served for several decades as a model for the study of sensory systems organization in the brain.
The images contained in this section were derived from assays directed at understanding neurochemical properties of circuits involved in hearing, and the interactions between hearing and other sensory modalities.

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Auditory, sensory and multi sensory cortical areas
Assays in this section profile expression of two markers in sensory and multi sensory areas of the cortex in cats:
  • Acetylcholinesterase (AChE)
  • Vesicular glutamate transporter protein (VGluT2)
AChE breaks down acetylcholine after release.
VGluT2 is involved in the storage and release of glutamate in synaptic vesicles. VGluT2 is most strongly expressed in thalamocortical axon terminals.

Multifluorescent immunohistochemical assays in this section combine VGluT2 and the neuronal marker NeuN to show laminar relationships.

The laminar distributions of AChE and VGluT2 are very similar in most cortical areas, with peak expression in thalamorecipient layers.

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Calcium-binding proteins in the thalamus
The calcium binding family of proteins is a large group of proteins involved in the cytosolic buffering of calcium.

Three major classes found in the cortex and thalamus of the brain are:
  • Parvalbumin (PV)
  • Calbindin (CB)
  • Calretinin(CR)
Each of these proteins has been linked to particular cell types (generally glutamatergic or GABAergic).

Glutamate decarboxylase 67 (GAD67)
GAD67 is involved in the synthesis of GABA and is broadly distributed in the somatic cytoplasm of neurons. The marker was used here to identify GABAergic neurons in the MGB that coexpress one or more of the calcium binding proteins.