The serotonin (5-hydroxytryptamine, 5-HT) system modulates many important brain functions and is critically involved in many neuropsychiatric disorders. Here, we present a high-resolution, multidimensional, in vivo atlas of four of the human brain's 5-HT receptors (5-HT1A, 5-HT1B, 5-HT2A, and 5-HT4) and the 5-HT transporter (5-HTT). The atlas is created from molecular and structural high-resolution neuroimaging data consisting of positron emission tomography (PET) and magnetic resonance imaging (MRI) scans acquired in a total of 210 healthy individuals. Comparison of the regional PET binding measures with postmortem human brain autoradiography outcomes showed a high correlation for the five 5-HT targets and this enabled us to transform the atlas to represent protein densities (in picomoles per milliliter). We also assessed the regional association between protein concentration and mRNA expression in the human brain by comparing the 5-HT density across the atlas with data from the Allen Human Brain atlas an...

We developed experimental techniques to study the neural substrates of goal-directed oculomotor behavior in trained rhesus macaques using a high-field 4.7 T vertical MRI scanner. We recorded BOLD activity, eye movements, reward and timing information while monkeys performed direct and memory saccades to visual cues during GE-EPI scans. Using a saccade vs. fixation block design, we obtained reliable activation maps of cortical and subcortical structures implicated in eye movement control. Next we compared BOLD responses during direct and memory saccades, in order to extract spatial-specific memory and/or planning signals. However, differential activation between memory and direct saccades in the block design was obscured, in part because block activity comprises signals from several task-related components. We therefore utilized an event-related design to delineate contributions from different epochs within the task sequence - presentation of visual cues, motor planning, spatial memory, saccade execution, a...

BACKGROUND: Multitrauma involves injury to at least two body regions, and is prevalent worldwide. Traumatic brain injury (TBI) and bone fracture are two of the most common components of multitrauma. We have recently demonstrated that this injury combina...

Impairment in social function is one of the core deficits of autism spectrum disorder (ASD) and a prominent feature of schizophrenia (SZ). The neural circuit basis of impaired social function in disease states is only beginning to be understood with evi...

Prior research has established specific nuclei of the brainstem, namely the locus coeruleus and the dorsal raphe nucleus, as the earliest sites of tau pathology in Alzheimer’s disease (AD). However, few studies have examined the utility of brainstem str...

Background: Hypnosis is the oldest form of Western psychotherapy and serves as a powerful evidence-based tool in the treatment of many disorders. Hypnotizability is a stable trait over time, suggesting neurophysiological factors underlying hypnotic resp...

Alcohol, tobacco, & cannabis are the most commonly used substances during adolescence (Johnston, O’Malley, Miech, Bachman, & Schulenberg, 2017). In fact, approximately 61%, 28%, and 45% of adolescents report using alcohol, tobacco, & cannabis, respectiv...

Introduction. Myelin is an important component of the white matter (WM) that wraps axons and promotes efficient conduction of action potentials. The relationship between axonal diameter and myelin sheath thickness is established by the g-ratio, which is...

It is controversial about the human somatotopic representation of orofacial areas, especially of the teeth. In addition, some studies of the postcentral somatosensory cortices of the non-human primates support a hierarchical scheme for information processing: the receptive field size and complexity increase with caudal progression. But there are few studies about hierarchical scheme in the orofacial area of the human. To verify human somatosensory orofacial representation including teeth and to show a hierarchal structure of this area, we conducted functional MRI. Tactile stimuli were applied to the forehead, lower lip, chin, tongue, and teeth. Our expectation was that the separated somatotopic representation in the rostral portion of the postcentral gyrus (PoCG) will be merging with caudal progression. Hence we compared the activated foci in the rostral PoCG nearby the central sulcus and those in the caudal portion nearby the postcentral sulcus. The foci activated by each stimulus were characterized by me...

Introduction. Electrophysiological studies (Chino, Calford, Heinen, Gilbert, Kaas, Rosa) suggest that adult V1 visual field maps reorganize after de-afferentiation. The reported electrophysiological reorganization appears inconsistent with cytochrome oxidase staining patterns after similar de-afferentiation (Horton & Hocking, J Neurosci 1998). We are measuring macaque V1 responses with functional magnetic resonance imaging (fMRI) and electrophysiology to clarify the extent of V1 reorganization. Methods. A retinal photocoagulation laser (GYC-2000, NIDEK) was used to lesion 5-8 degree homonymous visual field locations in four adult rhesus macaques. The retinal lesion creates a de-afferentiated V1 zone referred to as the lesion projection zone, or LPZ (Schmid et al., Cerebral Cortex 1996). As expected, following the lesion we found little or no response to visual stimulation inside the LPZ using functional magnetic resonance imaging (fMRI) at 4.7T in the anesthetized macaque preparation (Logothetis et al., Na...