Magnetic resonance imaging (MRI) is a valuable technique in the study of comparative neuroanatomy. MRIs allow visualization of the brain¹s structures in normal three-dimensional (3D) arrangement while avoiding the accumulation of artifacts associated with histological procedures. Additionally, 3D MRI datasets are compatible with geometric morphometric analyses not possible with histological samples. The Great Ape Aging Project, a comparative neurobiology of aging resource, has collected over 50 brain specimens of great apes on loan from zoological gardens and research centers. Using a 1.5 Tesla MRI scanner, high-resolution T1 and T2 weighted scans of postmortem brains (age range=19-51) from chimpanzees (n=10), gorillas (n=2), and orangutans (n=2) have been obtained in axial, coronal, and sagittal planes. 3D surface reconstructions have also been made. The high quality of these materials permitted the development of MRI-based brain anatomic atlases in these species with a high level of spatial resolution. T...

Resting-state networks (RSNs) are increasingly forwarded as candidate biomarkers for neuropsychiatric disorders. Such biomarkers may provide objective measures for evaluating novel therapeutic interventions in nonhuman primates often used in translational neuroimaging research. This study aimed to characterize the RSNs of awake squirrel monkeys and compare the characteristics of those networks in adolescent and adult subjects. Twenty-seven squirrel monkeys [ n  = 12 adolescents (6 male/6 female) ∼2.5 years and n  = 15 adults (7 male/8 female) ∼9.5 years] were gradually acclimated to awake scanning procedures; whole-brain fMRI images were acquired with a 9.4 T scanner. Group-level independent component analysis (ICA; 30 ICs) with dual regression was used to detect and compare RSNs. Twenty ICs corresponding to physiologically meaningful networks representing a range of neural functions, including motor, sensory, reward, and cognitive processes, were identified in both adolescent and adult monkeys. The reprod...

Studies of patients with focal brain injury indicate that smell perception involves caudal orbitofrontal and medial temporal cortices, but a more precise functional organization has not been characterized. In addition, although it is believed that odors are potent triggers of emotion, support for an anatomical association is scant. We sought to define the neural substrates of human olfactory information processing and determine how these are modulated by affective properties of odors. We used event-related functional magnetic resonance imaging (fMRI) in an olfactory version of a classical conditioning paradigm, whereby neutral faces were paired with pleasant, neutral, or unpleasant odors, under 50% reinforcement. By comparing paired (odor/face) and unpaired (face only) conditions, odor-evoked neural activations could be isolated specifically. In primary olfactory (piriform) cortex, spatially and temporally dissociable responses were identified along a rostrocaudal axis. A nonhabituating response in posteri...

The common marmoset (Callithrix jacchus), a New World Primate, is becoming increasingly popular as a non-human primate model for human brain function and dysfunction. To identify the functional network in marmoset, resting state functional MRI (RS-fMRI)...

After stroke onset, the degenerative reactions were activated leading to cell death and affecting neural repair. Stem cell administration shows an attractive therapeutic approach that reduces inflammation and enhances brain reorganization. Diffusion kur...

Humans have an amazing ability to remember daily episodes without efforts or intentions. Previous studies showed that neural activity in the human medial temporal lobes (MTL) can predict subsequent memory performance, i.e., subsequent memory effect (SME...

Functional MRI in conscious animals provides a new opportunity in drug discovery to identify patterns of brain activity characteristic of different classes of psychotropic molecules. To this end, rats were tested with functionally different classes of drugs used to treat schizophrenia - atypical (clozapine, respiridone) and typical (chlorpromazine, haloperidol) antipsychotics. Rats showed a dose-dependent (change in brain activity dominated by negative BOLD signal) within 10-15 min of iv injection of drug. Since the efficacy of these drugs is related, in part, to their affinity for dopamine receptors, animals were challenged with an ICV injection of apomorphine following neuroleptic treatment. While several areas of the brain were activated by apomorphine administration alone, the most robust increase in BOLD signal intensity occurred in the prefrontal cortex. The typical antipsychotics, haloperidol and chlorpromazine blocked the action of apomorphine in the prefrontal cortex, while respiradol and clozapin...

The search for imaging biomarkers of Parkinson’s Disease (PD) has predominantly been focused on measures of the substantia nigra (SN), often with mixed or contradictory results. Few studies have investigated the subthalamic nucleus (STN). The STN is a s...

The development of manganese as a transneuronally-transported, MRI-visible tract tracer has made in vivo identification of multi-stage anatomical pathways feasible. Using this technique, we can localize sites to which groups of neurons project, and target neuronal recordings from directly connected regions. Because manganese is a known neurotoxin, however, we need to determine to what extent intracerebral injections of this tracer result in neuronal damage. We injected manganese chloride (MnCl2, 0.5uL, 800mM) into the orbitofrontal cortex (OFC) of a rhesus monkey. We obtained high-resolution 3D MR images of the brain at 4.7T, with contrast optimized for Mn. We recorded single neurons in OFC while the monkey performed a color detection task before and after Mn injections. Finally, we processed the brain tissue histochemically for Nissl substance, tyrosine hydroxylase, and parvalbumin. Manganese injection sites were centered in area 13 of OFC. On post-injection day 4, we observed enhancements due to Mn trans...

We developed and implemented Functional MRI (fMRI) method, capable of delivering high-resolution definition of regionally specific brain activities as real-time biofeedback signal. We postulated that the feedback of brain function (i.e. neurofeedback) would assist subjects to achieve significant degree of modulation in the primary and secondary auditory areas by adjusting the level of attention to the incoming auditory stimuli. The experiment was conducted at high-field (3 Tesla) MR system, with near real-time fMRI data processing and anatomical segmentation capability. Five healthy volunteers participated in the fMRI examination, which consisted of six baseline scan sessions (three pre- and three post-neurofeedback trials) and five neurofeedback trial sessions. A reference scan session was conducted to delineate the target modulatory areas in the transverse temporal gyrus. In each fMRI session, auditory stimuli (computer generated 850Hz tone with +/- 30% bandwidth frequency modulation at 4Hz oscillation) ...