Auditory activation of "visual" cortical areas in the blind mole rat (Spalax ehrenbergi).
The mole rat (Spalax ehrenbergi) is a subterranean rodent whose adaptations to its fossorial life include an extremely reduced peripheral visual system and an auditory system suited for the perception of vibratory stimuli. We have previously shown that in this blind rodent the dorsal lateral geniculate nucleus, the primary visual thalamic nucleus of sighted mammals, is activated by auditory stimuli. In this report we focus on the manifestation of this cross-modal compensation at the cortical level. Cyto- and myeloarchitectural analyses of the occipital area showed that despite the almost total blindness of the mole rat this area has retained the organization of a typical mammalian primary visual cortex. Application of the metabolic marker 2-deoxyglucose and electrophysiological recording of evoked field potentials and single-unit activity disclosed that a considerable part of this area is activated by auditory stimuli. Previous neuronal tracing studies had revealed the origin of the bulk of this auditory input to be the dorsal lateral geniculate nucleus which itself receives auditory input from the inferior colliculus.
Bronchti
Gilles
G
Department of Zoology, George S. Wise Faculty of Life Sciences Tel Aviv University, IL-69978 Tel Aviv, Israel. Gilles_Bronchti@uqtr.ca
Heil
Peter
P
Sadka
Ronen
R
Hess
Andreas
A
Scheich
Henning
H
Wollberg
Zvi
Z
D000161:Acoustic Stimulation; D000200:Action Potentials / Q000502:physiology; D000818:Animals; D001303:Auditory Cortex / Q000166:cytology / Q000502:physiology; D001306:Auditory Pathways / Q000166:cytology / Q000502:physiology*; D001307:Auditory Perception / Q000502:physiology*; D001766:Blindness / Q000503:physiopathology*; D001931:Brain Mapping; D003623:Dark Adaptation / Q000502:physiology; D003847:Deoxyglucose; D005072:Evoked Potentials, Auditory / Q000502:physiology; D005073:Evoked Potentials, Somatosensory / Q000502:physiology; D008465:Mechanoreceptors / Q000502:physiology; D019577:Mole Rats / Q000033:anatomy & histology / Q000502:physiology*; D009473:Neuronal Plasticity / Q000502:physiology*; D009474:Neurons / Q000166:cytology / Q000502:physiology; D010812:Physical Stimulation; D013003:Somatosensory Cortex / Q000166:cytology / Q000502:physiology; D014738:Vibrissae / Q000502:physiology; D014793:Visual Cortex / Q000166:cytology / Q000502:physiology*; D014795:Visual Pathways / Q000166:cytology / Q000502:physiology*
D003847:Deoxyglucose