Lesion correlates of impaired acoustic-phonetic perception after unilateral left hemisphere stroke.

Acoustic-phonetic perception refers to the ability to perceive and discriminate between speech sounds. Acquired impairment of acoustic-phonetic perception is known historically as "pure word deafness" and typically follows bilateral lesions of the cortical auditory system. The extent to which this deficit occurs after unilateral left hemisphere damage and the critical left hemisphere areas involved are not well defined.

Interhemispheric Connectivity of the Human Temporal Lobes.

Unlabelled: Much is known regarding the major white matter pathways connecting the right and left temporal lobes, which project through the posterior corpus callosum, the anterior commissure, and the dorsal hippocampal commissure. However, details about the spatial location of these tracts are unclear, including their exact course and proximity to cortical and subcortical structures, the spatial relations between corpus callosum and anterior commissure projections, and the caudal extent of transcallosal connections within the splenium. We present an atlas of these tracts derived from high angular resolution diffusion tractography maps, providing improved visualization of the spatial relationships of these tracts.

Spatial correspondence of cortical activity measured with whole head fNIRS and fMRI: Toward clinical use within subject.

Functional near infrared spectroscopy (fNIRS) and functional magnetic resonance imaging (fMRI) both measure the hemodynamic response, and so both imaging modalities are expected to have a strong correspondence in regions of cortex adjacent to the scalp. To assess whether fNIRS can be used clinically in a manner similar to fMRI, 22 healthy adult participants underwent same-day fMRI and whole-head fNIRS testing while they performed separate motor (finger tapping) and visual (flashing checkerboard) tasks. Analyses were conducted within and across subjects for each imaging approach, and regions of significant task-related activity were compared on the cortical surface.

Semantic network activation facilitates oral word reading in chronic aphasia.

People with aphasia often show partial impairments on a given task. This trial-to-trial variability offers a potential window into understanding how damaged language networks function. We test the hypothesis that successful word reading in participants with phonological system damage reflects semantic system recruitment.

Comparison of Whole-Head Functional Near-Infrared Spectroscopy With Functional Magnetic Resonance Imaging and Potential Application in Pediatric Neurology.

Background: Changes in cerebral blood flow in response to neuronal activation can be measured by time-dependent fluctuations in hemoglobin species within the brain; this is the basis of functional magnetic resonance imaging (fMRI) and functional near-infrared spectroscopy (fNIRS). There is a clinical need for portable neural imaging systems, such as fNIRS, to accommodate patients who are unable to tolerate an MR environment.

Objective: Our objective was to compare task-related full-head fNIRS and fMRI signals across cortical regions.

Functional Near-Infrared Spectroscopy and Its Clinical Application in the Field of Neuroscience: Advances and Future Directions.

Similar to functional magnetic resonance imaging (fMRI), functional near-infrared spectroscopy (fNIRS) detects the changes of hemoglobin species inside the brain, but via differences in optical absorption. Within the near-infrared spectrum, light can penetrate biological tissues and be absorbed by chromophores, such as oxyhemoglobin and deoxyhemoglobin. What makes fNIRS more advantageous is its portability and potential for long-term monitoring.

Striatal dopamine D2/3 receptor-mediated neurotransmission in major depression: Implications for anhedonia, anxiety and treatment response.

Dopamine (DA) neurotransmission within the brain's reward circuit has been implicated in the pathophysiology of depression and in both, cognitive and pharmacological mechanisms of treatment response. Still, a direct relationship between measures of DA neurotransmission and reward-related deficits in patients with depression has not been demonstrated. To gain insight into the symptom-specific alterations in the DA system in patients with depression, we used positron emission tomography (PET) and the D receptor-selective radiotracer [C]raclopride in twenty-three non-smoking un-medicated Major Depressive Disorder (MDD) patients and sixteen healthy controls (HC).

Dopamine D2/D3 imbalance during migraine attack and allodynia in vivo.

Objective: To evaluate in vivo the dynamics of endogenous dopamine (DA) neurotransmission during migraine ictus with allodynia.

Methods: We examined 8 episodic migraineurs and 8 healthy controls (HC) using PET with [C]raclopride. The uptake measure of [C]raclopride, nondisplaceable binding potential (BP), would increase when there was a reduction in endogenous DA release.

Oxytocin modulates hemodynamic responses to monetary incentives in humans.

Rationale: Oxytocin is a neuropeptide widely recognized for its role in regulating social and reproductive behavior. Increasing evidence from animal models suggests that oxytocin also modulates reward circuitry in non-social contexts, but evidence in humans is lacking.

Objectives: We examined the effects of oxytocin administration on reward circuit function in 18 healthy men as they performed a monetary incentive task.

Salience Network Functional Connectivity Predicts Placebo Effects in Major Depression.

Background: Recent neuroimaging studies have demonstrated resting-state functional connectivity (rsFC) abnormalities among intrinsic brain networks in Major Depressive Disorder (MDD); however, their role as predictors of treatment response has not yet been explored. Here, we investigate whether network-based rsFC predicts antidepressant and placebo effects in MDD.

Methods: We performed a randomized controlled trial of two weeklong, identical placebos (described as having either "active" fast-acting, antidepressant effects or as "inactive") followed by a ten-week open-label antidepressant medication treatment.

Valence-specific effects of BDNF Val66Met polymorphism on dopaminergic stress and reward processing in humans.

Brain-derived neurotrophic factor (BDNF) levels in dopaminergic (DA) cells within the ventral tegmental area (VTA)/nucleus accumbens (NAc) circuitry appear to be a candidate mechanism for the neuroadaptive changes that follow stress and reward responses in animal models. However, the role of the BDNF gene variants in responses to salient cues through DA neurotransmission in humans remains unexplored. Here, we studied the effect of the common functional BDNF Val(66)Met (rs6265) polymorphism on rewarding experiences in the striatum and DA-mediated responses to stress.