Is the perirhinal cortex involved in working memory? Open Access

Weiss, Alison Ruth (2014)

Permanent URL: https://etd.library.emory.edu/concern/etds/70795830f?locale=en
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Abstract

The goal of this research was to characterize the nature of working memory (WM) deficits in monkeys with neonatal ibotenic acid lesions of the perirhinal cortex (PRh). Neonatal lesions of the PRh transiently impaired learning performance in a delayed non-match to sample task using session-unique stimuli at a short (5-sec) delay, but this mild impairment was not seen when the animals were re-tested with longer delays of 30s. In contrast, the same neonatal lesions severely impacted acquisition of a self-ordered object task (Obj-SO). Furthermore, the source of the errors from the Neo-PRh monkeys on the Obj-SO task differed from controls: although both groups made more primary errors on trial 3 than trial 2, the number of perseverative errors increased across trials only in the Neo-PRh group. Thus, the results indicate that neonatal perirhinal lesions had a greater impact on WM monitoring processes than on WM maintenance processes.

Table of Contents

Table of Contents

INTRODUCTION 1

METHODS 4

Subjects 4

Neuroimaging and Surgical Procedures 6

Neuroimaging 6

Surgical 7

Lesion Assessment 8

Apparatus and Stimuli 9

Session-Unique Delayed Nonmatch-to-Sample (SU-DNMS) 9

Object Self-Ordered Task (Obj-SO) 10

Statistical Analyses 11

RESULTS 12

Lesion Extent 12

Session-Unique Delayed Nonmatch-to-Sample (SU-DNMS) 12

Object Self-Ordered Task (Obj-SO) 13

DISCUSSION 15

Maintaining representations in WM 15

Monitoring representations in WM 17

Comparison to Neo-H 18

Early-damage vs Adult-damage 19

FIGURES/TABLES 20

Figure 1: MR Images 20

Figure 2: Trials and Errors to criterion, SU-DNMS 21

Figure 3: Sessions to reach criterion, Obj-SO 22

Figure 4: Primary and Perseverative Errors across delays, Obj-SO 23

Table 1: Extent of Neo-PRh lesions 24

REFERENCES 25

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