The mode of projections of single locus coeruleus neurons to the cerebral cortex in rats.
Axonal distributions of single locus coeruleus neurons within the cerebral cortex were examined with antidromic stimulation technique combined with cortical lesions (frontal lobotomy and lobectomy). In urethan-anesthetized rats, stimulating electrodes were implanted in 10 points extending over nearly the entire cerebral cortex, and antidromic responses of single locus coeruleus neurons to stimulation of these stimulus sites were analysed. Fifty percent of locus coeruleus neurons examined were activated antidromically from at least one cortical point in the cerebral cortex. The pattern and extent of axonal distributions of single locus coeruleus neurons in the cortex appeared to vary from cell to cell. From the results obtained in rats with the cortical lesions, it is concluded that in addition to locus coeruleus neurons with intracortical axons running from rostral to caudal, there are the neurons projecting to the occipital cortex without innervating the frontal cortex and those projecting simultaneously to the frontal and occipital cortex with two axonal branches. There was no topographic order between the recording sites within the locus coeruleus and the projection sites in the cortex.
D000344:Afferent Pathways / Q000033:anatomy & histology; D000818:Animals; D002540:Cerebral Cortex / Q000033:anatomy & histology* / Q000502:physiology; D005071:Evoked Potentials; D005260:Female; D005625:Frontal Lobe / Q000502:physiology; D008125:Locus Coeruleus / Q000033:anatomy & histology* / Q000502:physiology; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D011930:Reaction Time / Q000502:physiology