title: Parvalbumin and calbindin expression in parallel thalamocortical pathways in a gleaning bat, Antrozous pallidus.
abstract: The pallid bat (Antrozous pallidus) listens to prey-generated noise to localize and hunt terrestrial prey while reserving echolocation to avoid obstacles. The thalamocortical connections in the pallid bat are organized as parallel pathways that may serve echolocation and prey localization behaviors. Thalamic inputs to the cortical echolocation call- and noise-selective regions originate primarily in the suprageniculate nucleus (SG) and ventral division of medial geniculate body (MGBv), respectively. Here we examined the distribution of parvalbumin (PV) and calbindin (CB) expression in cortical regions and thalamic nuclei of these pathways. Electrophysiology was used to identify cortical regions selective for echolocation calls and noise. Immunohistochemistry was used to stain for PV and CB in the auditory cortex and MGB. A higher percentage (relative to Nissl-stained cells) of PV(+) cells compared with CB(+) cells was found in both echolocation call- and noise-selective regions. This was due to differences in cortical layers V-VI, but not layers I-IV. In the MGB, CB(+) cells were present across all divisions of the MGB, with a higher percentage in the MGBv than the SG. Perhaps the most surprising result was the virtual absence of PV staining in the MGBv. PV staining was present only in the SG. Even in the SG, the staining was mostly diffuse in the neuropil. These data support the notion that calcium binding proteins are differentially distributed in different processing streams. Our comparative data, however, do not support a general mammalian pattern of PV/CB staining that distinguishes lemniscal and nonlemniscal pathways.
authors.affiliation: Department of Psychology and Graduate Neuroscience Program, University of California, Riverside, California, 92521.
authors.forename: Heather
authors.initials: H
authors.lastname: Martin del Campo
authors.forename: Kevin
authors.initials: K
authors.lastname: Measor
authors.forename: Khaleel A
authors.initials: KA
authors.lastname: Razak
mesh_terms: D000161:Acoustic Stimulation; D000818:Animals; D001303:Auditory Cortex / Q000033:anatomy & histology* / Q000502:physiology; D001307:Auditory Perception / Q000502:physiology; D064026:Calbindins / Q000378:metabolism*; D002452:Cell Count; D002685:Chiroptera / Q000033:anatomy & histology* / Q000502:physiology; D004455:Echolocation / Q000502:physiology; D005260:Female; D005829:Geniculate Bodies / Q000033:anatomy & histology / Q000502:physiology; D007091:Image Processing, Computer-Assisted; D007150:Immunohistochemistry; D008297:Male; D008839:Microelectrodes; D009434:Neural Pathways / Q000033:anatomy & histology / Q000502:physiology; D009474:Neurons / Q000166:cytology / Q000502:physiology; D010320:Parvalbumins / Q000378:metabolism*; D010784:Photomicrography; D020656:Posterior Thalamic Nuclei / Q000033:anatomy & histology / Q000502:physiology; D013788:Thalamus / Q000033:anatomy & histology* / Q000502:physiology
chemical_list: D064026:Calbindins; D010320:Parvalbumins
keywords: auditory cortex; calcium binding proteins; echolocation; medial geniculate body; parallel pathways; sound localization