The commissural transfer of the horizontal optokinetic signal in the rat: a c-Fos study.
We applied the Fos method in rats subjected to horizontal optokinetic stimulation (OKS) to study whether optokinetic information is transferred through the commissural pretectal fibres from one optic tract nucleus (NOT) to the opposite. In binocular as well as in monocular nasalward OKS, the highest Fos immunoreactivity was found in the NOT contralateral to the nasalward stimulation, as expression of the activation either of direction-selective cells and of commissural neurons. Even the opposite NOT showed many Fos-positive cells activated by the opposite nucleus throughout the commissural pretectal pathway. They might be the GABA positive cells, which are thought to allow the activation in one nucleus to be transformed into inhibition of the opposite side. In monocular temporalward OKS, the inhibition on direction-selective cells and the consequent silencing of commissural neurons caused the faint immunoreactivity in the NOT contralateral to eye stimulated. In the opposite nucleus the few Fos-positive cells emerged as a consequence of the lack of the normal tonic commissurally mediated inhibition.
Ferrari
Renata
R
Dipartimento di Scienze Biomediche, Università di Modena e Reggio Emilia, 41125 Modena, Italy. renata.ferrari@unimore.it
Fonda
Sergio
S
Corradini
Matteo
M
Biral
Giampaolo
G
D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D007839:Functional Laterality / Q000502:physiology*; D007150:Immunohistochemistry; D008297:Male; D008636:Mesencephalon / Q000033:anatomy & histology / Q000502:physiology*; D009039:Motion Perception / Q000502:physiology*; D009433:Neural Inhibition / Q000502:physiology; D009434:Neural Pathways / Q000033:anatomy & histology / Q000502:physiology; D009474:Neurons / Q000378:metabolism*; D009483:Neuropsychological Tests; D017120:Nystagmus, Optokinetic / Q000502:physiology*; D010775:Photic Stimulation; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism; D051381:Rats; D020318:Rats, Long-Evans; D009435:Synaptic Transmission / Q000502:physiology; D014795:Visual Pathways / Q000033:anatomy & histology / Q000502:physiology*; D005680:gamma-Aminobutyric Acid / Q000378:metabolism
D015415:Biomarkers; D016760:Proto-Oncogene Proteins c-fos; D005680:gamma-Aminobutyric Acid