title: Fornix, medial prefrontal cortex, nucleus accumbens, and mediodorsal thalamic nucleus: roles in a fear-based context discrimination task.
abstract: The goal of the present study was to evaluate the contributions of various brain structures anatomically and functionally linked to the hippocampus and amygdala in a fear-based context discrimination task. The brain areas of interest included the fornix, medial prefrontal cortex, mediodorsal (MD) thalamic nucleus, and nucleus accumbens. Damage to the MD thalamic nucleus and medial prefrontal cortex produced the largest impairment in context-specific fear responses. Damage to the fornix impaired some fear responses (freezing, ultrasonic vocalizations, defecation, and approach/avoidance) while leaving conditioned fear expression of heart rate and urination unaltered. Damage to the nucleus accumbens was also coupled with deficits in the discriminative expression of some (heart rate, urination, and ultrasonic vocalizations) but sparing of context-appropriate freezing, defecation, and approach/avoidance behaviors.
authors.affiliation: California National Primate Research Center, University of California, Davis, CA 95616, USA. eantoniadis@ucdavis.edu
authors.forename: Elena A
authors.initials: EA
authors.lastname: Antoniadis
authors.forename: Robert J
authors.initials: RJ
authors.lastname: McDonald
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001362:Avoidance Learning / Q000187:drug effects / Q000502:physiology; D004193:Discrimination Learning / Q000187:drug effects / Q000502:physiology*; D004777:Environment; D005239:Fear / Q000502:physiology*; D020712:Fornix, Brain / Q000187:drug effects / Q000502:physiology; D046352:Freezing Reaction, Cataleptic / Q000187:drug effects / Q000502:physiology; D006339:Heart Rate / Q000187:drug effects / Q000502:physiology; D008297:Male; D020645:Mediodorsal Thalamic Nucleus / Q000187:drug effects / Q000502:physiology*; D008845:Microinjections; D016202:N-Methylaspartate / Q000008:administration & dosage; D009434:Neural Pathways / Q000187:drug effects / Q000502:physiology*; D009498:Neurotoxins / Q000008:administration & dosage; D009714:Nucleus Accumbens / Q000187:drug effects / Q000502:physiology; D017397:Prefrontal Cortex / Q000187:drug effects / Q000502:physiology*; D011897:Random Allocation; D051381:Rats; D020318:Rats, Long-Evans
chemical_list: D009498:Neurotoxins; D016202:N-Methylaspartate