title: Comparable reduction in Zif268 levels and cytochrome oxidase activity in the retrosplenial cortex following mammillothalamic tract lesions.
abstract: Damage to the mammillothalamic tract (MTT) produces memory impairments in both humans and rats, yet it is still not clear why this diencephalic pathway is vital for memory. One suggestion is that it is an important route for midbrain inputs to reach a wider cortical and subcortical network that supports memory. Consistent with this idea, MTT lesions produce widespread hypoactivity in distal brain regions as measured by the immediate-early gene, c-fos. To determine whether these findings were selective to c-fos or reflected more general changes in neuronal function, we assessed the effects of MTT lesions on the expression of the immediate-early gene protein, Zif268 and the metabolic marker, cytochrome oxidase, in the retrosplenial cortex and hippocampus. The lesions decreased levels of both activity markers in the superficial and deep layers of the retrosplenial cortex in both its granular and dysgranular subregions. In contrast, no significant changes were observed in the hippocampus, despite the MTT-lesioned animals showing marked impairments on T-maze alternation. These findings are consistent with MTT lesions providing important, indirect inputs for normal retrosplenial cortex functioning. These distal functional changes may contribute to the memory impairments observed after MTT lesions.
authors.affiliation: School of Psychology, Cardiff University, Tower Building, Park Place, Cardiff CF10 3AT, UK; School of Biosciences, Cardiff University, Museum Avenue, Cardiff CF10 3AX, UK.
authors.forename: Aura
authors.initials: A
authors.lastname: Frizzati
authors.affiliation: School of Psychology, Cardiff University, Tower Building, Park Place, Cardiff CF10 3AT, UK; School of Biosciences, Cardiff University, Museum Avenue, Cardiff CF10 3AX, UK.
authors.forename: Michal M
authors.initials: MM
authors.lastname: Milczarek
authors.affiliation: School of Biosciences, Cardiff University, Museum Avenue, Cardiff CF10 3AX, UK.
authors.forename: Frank
authors.initials: F
authors.lastname: Sengpiel
authors.affiliation: School of Biosciences, Cardiff University, Museum Avenue, Cardiff CF10 3AX, UK.
authors.forename: Kerrie L
authors.initials: KL
authors.lastname: Thomas
authors.affiliation: School of Psychology, Cardiff University, Tower Building, Park Place, Cardiff CF10 3AT, UK; Institute of Neuroscience, Trinity College Dublin, Lloyd Building, College Green, Dublin 2, Ireland.
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Dillingham
authors.affiliation: School of Psychology, Cardiff University, Tower Building, Park Place, Cardiff CF10 3AT, UK. Electronic address: vannsd@cardiff.ac.uk.
authors.forename: Seralynne D
authors.initials: SD
authors.lastname: Vann
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D002452:Cell Count; D002540:Cerebral Cortex / Q000378:metabolism* / Q000473:pathology; D015331:Cohort Studies; D004195:Disease Models, Animal; D051766:Early Growth Response Protein 1 / Q000378:metabolism*; D004558:Electric Stimulation; D003576:Electron Transport Complex IV / Q000378:metabolism*; D006624:Hippocampus / Q000378:metabolism* / Q000473:pathology; D007150:Immunohistochemistry; D008326:Mammillary Bodies / Q000293:injuries / Q000378:metabolism* / Q000473:pathology; D018782:Maze Learning / Q000502:physiology; D008569:Memory Disorders / Q000209:etiology / Q000378:metabolism / Q000473:pathology; D009434:Neural Pathways / Q000293:injuries / Q000378:metabolism / Q000473:pathology; D051381:Rats; D013788:Thalamus / Q000293:injuries / Q000378:metabolism* / Q000473:pathology
chemical_list: D051766:Early Growth Response Protein 1; C486110:Egr1 protein, rat; D003576:Electron Transport Complex IV
keywords: anterior thalamic nuclei; diencephalic amnesia; hippocampus; immediate-early gene; mammillary bodies; memory