Publications by authors named "Joshua Dominic Rizak"
It is well known that dopamine (DA) is critical for reward, but the precise role of DA in reward remains uncertain. The aim of this study was to determine what percentage of dopaminergic neurons in the primate brain is required for the expression of conditioned reward by measuring the performance of DA-deficient rhesus monkeys in a morphine-induced conditioned place preference (CPP) paradigm. Animals with mild Parkinsonian symptoms successfully developed and retained a morphine preference that was equivalent to control monkeys.
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- Postpartum depression (PPD) affects mothers and infants and is more complex than major depressive disorders (MDD), often being overlooked due to its shorter duration and moderate symptoms, highlighting the need for better animal models for research.
- The study observed postpartum female cynomolgus monkeys for depressive behaviors, using huddle posture as an indicator of behavioral depression postpartum (BDP), identifying two groups: one exhibiting more depressive behavior and a control group.
- Findings indicated that the depressive behaviors in monkeys were not linked to external stressors, and interestingly, the BDP group showed unusual maternal behaviors, suggesting that cynomolgus monkeys are a valuable model for studying human postpartum depression due to their social structure and biological similarities.
Parkinson's disease (PD) is a chronic and progressive neurodegenerative disorder associated with decreased striatal dopamine levels. Morphine has been found to elevate dopamine levels, which indicates a potential therapeutic effect in PD treatment that has not been investigated previously. To evaluate this hypothesis, an investigation of the acute effects of morphine on PD symptoms was carried out in male rhesus PD monkeys that had been induced with MPTP.
View Article and Find Full Text PDFRecent developments in neuron recording techniques include the invention of some fragile electrodes. The fragility of these electrodes impedes their successful use in deep brain recordings because it is difficult to penetrate the electrodes through the dura mater, especially the tentorium cerebelli (TC) enclosing the cerebellum and brain stem. This paper reports a new method to pierce the TC for inserting fragile electrodes into the inferior colliculus of rhesus monkeys.
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- Social stress in animal societies can impact physiological stress levels and disease vulnerability, but how social rank affects stress varies by species and within groups.
- In a study of female rhesus macaques, cortisol levels were analyzed to understand stress related to dominance rank; results showed differing patterns between strict and less strict hierarchies.
- The findings highlight that the structure of a social hierarchy influences stress responses, which could help develop models for understanding rank-related stress and its implications for diseases connected to human social status.
The exposures to extremely low frequency magnetic field (ELF-MF) in our environment have dramatically increased. Epidemiological studies suggest that there is a possible association between ELF-MF exposure and increased risks of cardiovascular disease, cancers and neurodegenerative disorders. Animal studies show that ELF-MF exposure may interfere with the activity of brain cells, generate behavioral and cognitive disturbances, and produce deficits in attention, perception and spatial learning.
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