Perirhinal cortex ablation in rats selectively impairs object identification in a simultaneous visual comparison task.

Abstract

In Experiment 1, rats discriminated among computer-generated visual displays (scenes) comprising 3 different shapes (objects). One constant scene (unrewarded) appeared on every trial together with a trial-unique variable scene (rewarded). Four types of variable scene were intermingled: (a) unfamiliar objects in different positions from the constant; (b) unfamiliar objects in same positions as the constant; (c) same objects as the constant in different positions; (d) same objects and positions, recombined. Aspiration lesions of perirhinal cortex impaired performance with type (b) only. Experiment 2 tested spatial delayed nonmatching-to-sample. The perirhinal group were impaired nonsignificantly, and less than fornix-transected rats in an earlier study. Rats' perirhinal cortex, like monkeys', subserves object identification in the absence of memory requirement but does not contribute substantially to hippocampal system spatial memory function.

Recognition Memory for Complex Visual Discriminations Is Influenced by Stimulus Interference in Rodents With Perirhinal Cortex Damage

“…However, the data suggest that the hippocampus is not necessary for accurate visual object-recognition memory. The present results support the proposal that the PRC may serve similar functions in rodents and primates (Burwell et al 1995;Gaffan et al 2000), and the data offer support for the perceptual-mnemonic/feature conjunction model (Bussey et al 2003).…”

“…Therefore, further studies should be conducted to examine the role of the rodent PRC in resolving feature ambiguity. However, the results of the present experiment offer further support for the proposal that the PRC may serve similar functions in rodents and primates (Burwell et al 1995;Gaffan et al 2000).…”

“…Cold Spring Harbor Laboratory Press on May 11, 2018 -Published by learnmem.cshlp.org Downloaded from Gaffan 1998a,b;Bussey et al 1999Bussey et al , 2000Buffalo et al 2000;Gaffan et al 2000;Baxter and Murray 2001). In particular, a prior study in monkeys demonstrated that the primate PRC might resolve feature ambiguity in complex visual discriminations (Bussey et al 2002).…”

“…Recent data suggest that PRC lesions in rodents and nonhuman primates impair visual recognition and associative memory (Meunier et al 1993;Murray et al 1993;Mumby and Pinel 1994;Ennaceur et al 1996;Higuchi and Miyashita 1996;Wiig et al 1997;Buckley and Gaffan 1998a,b;Bussey et al 1999Bussey et al , 2000Buffalo et al 2000;Gaffan et al 2000;Baxter and Murray 2001). In addition, neurons in the PRC and adjacent inferotemporal cortex have been shown to respond less to a visual stimulus with repeated exposure (Desimone 1996;Brown and Xiang 1998;Suzuki and Eichenbaum 2000), suggesting that PRC neurons may be involved in memory for visual objects.…”

The rat perirhinal cortex: A review of anatomy, physiology, plasticity, and function

“…They suggest that in this capacity the perirhinal cortex acts as part of the ventral visual stream in addition to being part of the medial temporal lobe as it is traditionally classified. There have been a few studies in rats which have supported this view from primates that the perirhinal cortex may play a role in perceptual processes; rats with lesions of the perirhinal cortex are impaired on a memoryindependent visual discrimination task (Gaffan et al, 2000) and on a visual discrimination task where stimulus interference is employed (Gilbert and Kesner, 2003). Recently, antagonism of perirhinal GABA A , NMDA and muscarinic receptors in rats prior to training disrupts acquisition of an object recognition tasks which, although not conclusive, supports the PMFC model in that the task most likely relies on both perceptual and mnemonic processing .…”