Effects of neonatal destruction of the medial forebrain bundle in the cat: long-term neurochemical, locomotor, and regulatory deficits.
Neonatal kittens (N = 27) 11 to 22 days of age received bilateral electrolytic lesions of the medial forebrain bundle (MFB). These lesions transected the rostral course of the nigrostriatal tract, disrupted other fiber tracts that constitute the MFB, damaged the indigenous neurons of the lateral hypothalamic region, and interrupted striatal output pathways. The behavioral development of these animals was assessed and compared with that of intact littermates (N = 37) and a group of littermates that received lesions that did not encroach upon the MFB (control lesions, N = 16). The MFB lesions produced transient periods of decreased body weight gains. Animals with large MFB lesions had to be tube fed for various periods. Decreased ponderal weight in animals with large MFB lesions occurred throughout the duration of their survival (1 to 2 years of age). Development of locomotor activity was assessed in an open field. At about 6 weeks of age animals with MFB lesions became hyperactive compared with their intact littermates and this hyperactivity was still apparent at 6 months of age when testing was discontinued. Caudate dopamine and tyrosine hydroxylase were measured after the animals were killed. Large MFB lesions produced a marked decrease in concentrations of caudate dopamine (75%) and the activity of tyrosine hydroxylase (62%). These results indicate that early postnatal damage to the MFB in cats produces a constellation of behavioral deficits that differ both quantitatively and qualitatively from the effects of similar lesions produced in the adult animal.
D000818:Animals; D000831:Animals, Newborn / Q000254:growth & development*; D001143:Arousal / Q000502:physiology; D001288:Attention / Q000502:physiology; D001522:Behavior, Animal / Q000502:physiology*; D001835:Body Weight; D001921:Brain / Q000201:enzymology / Q000378:metabolism; D002415:Cats; D004298:Dopamine / Q000032:analysis; D005260:Female; D008297:Male; D008474:Medial Forebrain Bundle / Q000032:analysis / Q000378:metabolism / Q000502:physiology*; D009043:Motor Activity / Q000502:physiology*; D009434:Neural Pathways / Q000502:physiology*; D009638:Norepinephrine / Q000032:analysis; D014446:Tyrosine 3-Monooxygenase / Q000032:analysis
D014446:Tyrosine 3-Monooxygenase; D004298:Dopamine; D009638:Norepinephrine