Excitotoxic Lesions of the Amygdala Fail to Produce Impairment in Visual Learning for Auditory Secondary Reinforcement But Interfere with Reinforcer Devaluation Effects in Rhesus Monkeys

The amygdala and orbital prefrontal cortex (PFo) interact as part of a system for affective processing. To assess whether there is a hemispheric functional specialization for the processing of emotion or reward or both in nonhuman primates, rhesus monkeys ( Macaca mulatta) with combined lesions of the amygdala and PFo in one hemisphere, either left or right, were compared with unoperated controls on a battery of tasks that tax affective processing, including two tasks that tax reward processing and two that assess emotional reactions. Although the two operated groups did not differ from each other, monkeys with unilateral lesions, left and right, showed altered reward-processing abilities as evidenced by attenuated reinforcer devaluation effects and an impairment in object reversal learning relative to controls. In addition, both operated groups showed blunted emotional reactions to a rubber snake. By contrast, monkeys with unilateral lesions did not differ from controls in their responses to an unfamiliar human (human “intruder”). Although the results provide no support for a hemispheric specialization of function, they yield the novel finding that unilateral lesions of the amygdala-orbitofrontal cortical circuit in monkeys are sufficient to significantly disrupt affective processing.

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Environmental Effect of HV Towers at the Cerebellum and Cognitive Impairments in the Monkey

Basic and Clinical Neuroscience Journal ◽

10.32598/bcn.2021.1340.5 ◽

2021 ◽

pp. 1-24

Author(s):

Hamed Aliyari ◽

◽

Hedayat Sahraei ◽

Mohammad Bagher Menhaj ◽

Masoomeh Kazemi ◽

...

Keyword(s):

High Voltage ◽

Rhesus Monkeys ◽

Visual Learning ◽

Rt Pcr ◽

Electrical Field ◽

Cerebral Mri ◽

Before And After ◽

Pcr Method ◽

Cerebellar Anatomy ◽

Male Rhesus

Today, living or working of people in the vicinity and even under the high-voltage lines is a pernicious environmental hazard to humans. The male rhesus monkey is used to investigate the effects of fields produced by high-voltage towers. In this study, the function and level of effect in rhesus monkeys' brain have been investigated in cerebellum's cognitive, biological and structural perspective. Two monkeys have been used, one as a control and the second under test. The monkey under test was subjected to a simulated HV electrical field of 3 kV/m for 4 hours a day for a one month. Behavioral tests were performed using a device designed and built for this purpose. Concentration analysis of adrenocorticotropic hormones (ACTH) and inspection of glucocorticoid receptor gene's (GR) expression were performed by the RT-PCR method. Changes in cerebellar anatomy with MRI images were examined. All tests were performed before and after the test period and were compared with the control monkey. Cognitive tests showed a significant reduction for the monkey that was exposed to a high-voltage electrical field in the first week after field imposition compared with the same time before. Also, the expression of the GR gene was decreased and the concentration of ACTH hormone in plasma was increased. Surveying the level of cerebral MRI images did not show any difference, but hemorrhage was evident in a part of the cerebellum. The results of cognitive, biological and MRI tests in the tested monkey showed a decrease in the visual learning and memory indices.

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The Growth of Herpesvirus mulatto in Human Fibroblast

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100051232 ◽

1974 ◽

Vol 32 ◽

pp. 244-245

Author(s):

Glennelle Washington ◽

Philip P. McGrath ◽

Peter R. Graze ◽

Ivor Royston

Keyword(s):

Rhesus Monkey ◽

Microscopic Study ◽

Electron Microscopic Study ◽

Peripheral Blood ◽

Human Fibroblast ◽

Rhesus Monkeys ◽

Human Fibroblasts ◽

Electron Microscopic ◽

Specific Antisera ◽

Peripheral Blood Leucocytes

Herpes-like viruses were isolated from rhesus monkey peripheral blood leucocytes when co-cultivated with WI-38 cells. The virus was originally designated rhesus leucocyte-associated herpesvirus (LAHV) and subsequently called Herpesvirus mulatta (HVM). The original isolations were from juvenile rhesus monkeys shown to be free of antibody to rhesus cytomegalic virus. The virus could only be propagated in human or simian fibroblasts. Use of specific antisera developed from HVM showed no relationship between this virus and other herpesviruses. An electron microscopic study was undertaken to determine the morphology of Herpesvirus mulatta (HVM) in infected human fibroblasts.

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Nucleolar Segregation and Chronic Methanol Intoxication

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100063718 ◽

1969 ◽

Vol 27 ◽

pp. 360-361

Author(s):

Julio H. Garcia ◽

Janice P. Van Zandt

Keyword(s):

Body Weight ◽

Methyl Alcohol ◽

Rhesus Monkeys ◽

Repeated Administration ◽

Serum Levels ◽

Methanol Intoxication ◽

Intragastric Tube ◽

Nucleolar Segregation

Repeated administration of methyl alcohol to Rhesus monkeys (Maccaca mulata) by intragastric tube resulted in ultrastructural abnormalities of hepatocytes, which persisted in one animal twelve weeks after discontinuation of the methyl alcohol regime. With dosages ranging between 3.0 to 6.0 gms. of methanol per kg. of body weight, the serum levels attained within a few hours averaged approximately 475 mg. per cent.

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