RESUMEN
The role of the posterior parahippocampal area of the brain in spatial types of memory in conditions of one-trial visual perception of the positions of objects was studied by training eight cats to remember the spatial positions of either two different objects covering two of three feeders placed on a test tray (tests for the "object-place" association) or the positions of two of three feeders (tests for place). Each trial used new objects and new positions for the two of three feeders. After training, four cats were subjected to electrolytic lesioning of the posterior parahippocampal area, primarily the parahippocampal cortex, parasubiculum, and presubiculum; the remaining four cats underwent all the surgical procedures except electrocoagulation of nervous tissue; this was the sham-operated control group. Cats of this group showed no impairment to the performance of tests of both types, while the experimental group showed similar levels of impairment to the performance of both tests. Thus, memory for one-trial perception of "object-place" associations and, more simply, two different object places in cats were critically dependent on the posterior parahippocampal area.
Asunto(s)
Hipocampo/fisiopatología , Memoria/fisiología , Reconocimiento Visual de Modelos/fisiología , Percepción Espacial/fisiología , Animales , Mapeo Encefálico/métodos , Gatos , Femenino , Masculino , Giro Parahipocampal/fisiopatologíaRESUMEN
To determine the contribution of the posterior parahippocampal region to spatial form of one-trial memory in cats, we trained 8 cats to remember the spatial positions of either two different trial-unique objects overlying two of three feeders in a feeder test tray (object-place trials) or simply two of the three feeders (place trials). Four cats then received electrolytic lesions restricted to the posterior parahippocampal region (experimental group) including mainly parahippocampal cortex, parasubiculum and presubiculum. Four other cats comprised sham-operated control group. This group was found to be completely unaffected postoperatively in both types of trials, whereas experimental group showed impaired performance in both types of trials equally. Thus, one-trial memory for object-place association and one-trial memory for two different places in cats appear to be critically dependent on the posterior parahippocampal region.
Asunto(s)
Hipocampo/fisiopatología , Memoria/fisiología , Reconocimiento Visual de Modelos/fisiología , Percepción Espacial/fisiología , Animales , Mapeo Encefálico/métodos , Gatos , Femenino , Masculino , Giro Parahipocampal/fisiopatologíaRESUMEN
Memory for visual recognition in primates is at least partially mediated by the peripheral and entorhinal (i.e., rhinal) areas of the cerebral cortex. The roles of these structures in visual recognition in cats was studied by producing electrolytic combined lesions of the rhinal (perirhinal + entorhinal) areas in a group of cats trained in a modified Wisconsin test apparatus to delayed selection of an object on the basis of its image on presentation of a new object in every trial in the test. Control groups consisted of intact and sham-operated cats. Animals with rhinal lesions were no different from sham-operated and intact animals in the initial training to the rules for correct responding to the objects presented; they also showed no difference at the minimum delay period of 5 sec used in these experiments. However, a statistically significant difference was seen on testing with a delay of 10 sec, demonstrating impairment of intrinsic visual recognition memory.
Asunto(s)
Corteza Cerebral/fisiología , Sistema Límbico/fisiología , Reconocimiento en Psicología/fisiología , Percepción Visual/fisiología , Animales , Gatos , Condicionamiento Clásico/fisiología , Corteza Entorrinal/fisiología , Femenino , Masculino , Giro Parahipocampal/fisiología , Estimulación Luminosa , Vías Visuales/fisiologíaRESUMEN
Visual recognition memory in primates is mediated at least in part by the perirhinal and entorhinal (i.e., rhinal) cortices. To examine the role of these structures in cats' visual recognition memory, we performed combined electrolytic rhinal (perirhinal and entorhinal) lesions in a group of cats trained in visual delayed matching-to-sample with trial-unique objects in the modified Wisconsin General Testing Apparatus. Sham-operated and intact cats were used as control groups. Cats with rhinal lesions did not differ from the control sham-operated and unoperated groups in initial learning of the rules of the task; difference between experimental and control groups under conditions of minimum 5-sec delay was nonsignificant as well. However, significant difference between experimental and control groups was revealed under conditions of testing with 10-sec delay. This finding suggests a disorder in the visual recognition memory.
Asunto(s)
Corteza Entorrinal/fisiología , Reconocimiento Visual de Modelos , Percepción Visual , Animales , Mapeo Encefálico/métodos , Gatos , Femenino , Masculino , Memoria a Corto Plazo , Tiempo de ReacciónRESUMEN
Cats learned a delayed reaction (DR) sooner than a delayed alternation (DA) in spite of the maximal drawing together of the testing parameters. Short-term memory was suggested to be involved in DR performance whereas DA was based on elaboration of a program of stereotype alternation. DA learning was more effective in an animal receiving additional information on the absence of food in the given food-well after a correct reaction. This fact indicated the use by the animal of the short-term memory about the absence of food in the visited food-well in DA test. The effect was not observed at the final stage of DA learning the alternation program having been assimilated. This accounts for strongly expressed deficiency of DA learning abilities in "prefrontal" cats.