کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
4330495 1614261 2007 7 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Participation of the dorsal hippocampus in stimulus discrimination with scopolamine
موضوعات مرتبط
علوم زیستی و بیوفناوری علم عصب شناسی علوم اعصاب (عمومی)
پیش نمایش صفحه اول مقاله
Participation of the dorsal hippocampus in stimulus discrimination with scopolamine
چکیده انگلیسی
Stimulus discrimination is the capacity of an organism to differentiate between stimuli and emit associated responses. The administration of the muscarinic antagonist scopolamine can be used as a stimulus by mammals in a discrimination task. The present study analyzes the contribution of the hippocampus in scopolamine discrimination and generalization. Male Wistar rats, weighing 250-300 g at the beginning of the experiment, were trained to discriminate between scopolamine (1.0 mg/kg, i.p.) and saline administration using a two-lever operant task; rats had to respond differentially to each lever depending on the preceding drug or saline administration. Once stimulus control was attained, rats were tested with different scopolamine doses (0.0, 0.056, 0.091, 0.16, 0.31 and 1.0 mg/kg, i.p.) in order to obtain generalization curves. After generalization the rats were randomly assigned to hippocampal CA1 lesion or control groups. Hippocampus impairment produced a transient decrease in the capacity to discriminate between scopolamine and saline conditions; nonetheless, scopolamine correct responses were rapidly recovered after a few sessions and even maintained after 90 days. Correct responses for saline condition were never recovered. The generalization curve obtained after hippocampus lesion showed a response gradient severely flattened. Results suggest that the hippocampus participates as a neural system supporting the sensitivity to detect discrete changes in stimulus properties and relational memory, more than on the capacity to recall for simple associative responses.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Brain Research - Volume 1178, 31 October 2007, Pages 125-131
نویسندگان
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