Our studies of cyclical E treatment in ovariectomized (OVX) young and aged rhesus monkeys have revealed compelling cognitive and synaptic effects of E in the context of aging.
Preclinical studies in aged, surgically-menopausal rhesus monkeys have revealed powerful benefits of intermittent estrogen injections on prefrontal cortex dependent working memory, together with corresponding effects on dendritic spine morphology in the prefrontal cortex.
Some of our previous studies with Campbell's monkeys have revealed an unusually high degree of vocal flexibility in various call types, often linked with social variables [21] [25].
Studies of visual object identification in humans and monkeys have revealed a progression of brain areas within the ventral and dorsal visual processing pathways (Ungerleider and Mishkin 1982; Ungerleider and Haxby 1994), as well as in the prefrontal cortex (e.g., Miller et al. 2002), that correspond to multiple, qualitatively distinct, and hierarchically organized levels of representation.
Moreover, single-cell neurophysiology studies in monkeys have revealed neurons with preferences for specific nonsymbolic numbers (e.g., an array of 4 dots) in the IPS, and a decrease in sensitivity as the numerical proximity to this number decreases (Nieder et al. 2002; Diester and Nieder 2007).
In support for this view, coherence estimates of intracranial recordings in monkeys have revealed task-related long-range interactions between cortical regions in several different tasks (attention, motor preparation/decision) and in multiple frequency bands [Buschman and Miller, 2007; Pesaran et al., 2008; Gregoriou et al., 2009].
Fifty years of modern research on the vocalizations of monkeys and apes has revealed many fascinating aspects of animal cognition, but has shown that the auditory communication systems of non-human primates are very unlike human language (Cheney and Seyfarth 1996; Hauser et al. 2002).
Over the last two decades or so, extensive laboratory research carried out on monkeys and apes [3] [6] has revealed the existence of non-verbal systems of numerical representation that non-human primates apparently share both with human infants and with human adults tested in comparable conditions [7], [8].
A team from Duke University scanned this ancient monkey fossil, first discovered in Kenya in 1997, and has revealed that its tiny brain was wrinkled and well defined, containing aspects that are actually more complex than its modern descendants.
Neurophysiology has revealed the existence of mirror neurons in the brain of macaque monkeys that activate when the monkey executes a goal directed behavior and also when it observes the same behavior performed by another.
