Emotion regulation (ER) can modulate both immediate (emotional experience) and long-term (episodic memory) effects of emotion. Previous studies have mainly focused on reappraisal and suppression, strategies known to engage extensive cognitive resources....

Spatial normalization is fundamental to multi-subject fMRI experiments as it facilitates a common space in which group analyses are performed. Commonly, experimental data is aligned to either a group template (e.g. MNI-152) or to an individual template ...

Reported associations between functional connectivity and affective disorder symptoms are minimally reproducible, which can partially be attributed to difficulty capturing highly variable clinical symptoms in cross-sectional study designs. “Dense sampling” protocols, where participants are sampled across multiple sessions, can overcome this limitation by studying associations between functional connectivity and variable clinical states. Here, we characterized effect sizes for the association between functional connectivity and time-varying positive and negative daily affect in a nonclinical cohort. Data were analyzed from 24 adults who attended four research visits, where participants self-reported daily affect using the PANAS-X questionnaire and completed 39 min of functional magnetic resonance imaging across three passive viewing conditions. We modeled positive and negative daily affect in relation to network-level functional connectivity, with hypotheses regarding within-network connectivity of the defa...

During adolescence, the dopaminergic system in the brain is undergoing dramatic processing that includes synaptic pruning and alteration in dopaminergic receptor numbers. We used phMRI to investigate the differences in neuronal responses to acute cocaine challenge in the adolescent and adult brain. Methods – Adolescent (22 days old, P22, n=7) and adult (>60 days old, n=6) Sprague-Dawley rats were used in this study. Rats were scanned in a 9.4T Bruker scanner under 1% halothane anesthesia with an acute cocaine challenge (0.5mg/kg, i.v.). Regional cerebral blood volume (rCBV) changes were assessed by using IRON method with echo planar imaging sequence (TR/TE 10ms/6ms). Dopamine (DA) release by microdialysis was assessed in the caudate/putamen in a separate group of P22 rats. Results – Cocaine challenge on the adult rats induced bi-phasic rCBV changes (negative followed by positive rCBV changes) in the caudate/putamen (CPU), Nucleus accumbens (NAc), medial prefrontal cortex (mPFC), and thalamus. Cocaine chall...

3-NP, a succinate dehydrogenase inhibitor, is widely used as an experimental model to study HD, energy metabolism and cell death. We used a rat model to investigate 3-NP induced acute and prolonged neurotoxicity using in vivo imaging of cerebral glucose utilization (CGU)and dopamine receptors by PET, neuroanatomy by MRI and neurochemicals by MRS. 3-NP was administered (male Spraque-Dawley) twice a day (10 mg/kg ip.) until symptomatic or max of 5 days. PET studies of CGU were conducted daily using a super high resolution (1.3x1.3x1.8 mm3) in-house built PET device. MRI and MRS studies were conducted with a GE Omega 4.7 T imager. Studies of CGU showed significant interanimal variation in the acute response of toxin, similar to motor activity. The average decrease of CGU in the lesions was 31+/-12% and the lesions started to develop on the first day of 3-NP. Four weeks later CGU was recovered to -13+/-5% and then in 3 months decreased again to –48+/-10%. Dopamine D1 and D2 receptors showed progressively decre...

Linguistic processing is a complex skill with several dissociable components, including semantic, phonological, and syntactic processing. The goal of the present study was to compare and contrast the patterns of cortical activity associated with each of these processes. Twelve healthy young adults were scanned while performing match-to-sample tasks meant to elicit three different types of language processing. The semantic task required choosing a synonym, the phonological task required choosing a rhyme from among two words ending with the same sequence of letters, and the syntactic task required choosing a verb to agree in number with a singular or plural noun. Each of these tasks was compared to a control task of choosing an identical match in an alternating block sequence. Thus the format of the stimulus and the format of the response remained constant across all conditions, and only the linguistic basis of the decision varied. Imaging was performed using a 1.5 T whole-body MRI scanner with a full head c...

We investigated somatosensory cortical activation in squirrel monkeys using high-field imaging (9.4T, Bruker) during vibrotactile and electrocutaneous stimulation of the hand. Accompanying high-resolution T1 anatomical experiments were used to define the laminar organization of SI. Vibrotactile stimulation was administered by piezoelectric elements that drove a circular contact (0.5 mm dia.) onto the surface of a digit segment. Electrocutaneous stimuli were presented via electrodes positioned on the digit volar surfaces and base of the palm. All stimuli were delivered in a blocked design. In T1-images, whole brain coverage was achieved with a 7 cm coil to achieve a 195µm in-plane resolution. For EPI data, a 3 cm coil was positioned over somatosensory cortex for a 625µm in-plane resolution. Isoflurane anesthesia (0.5-0.8%) was maintained by monitoring physiological variables (SpO2, BPM, CO2; see Cheney et al., this meeting). Data was acquired from two monkeys that were scanned over 20 fMRI sessions. Prelimi...

In this study we investigated how activity in the cerebellum is related to the ocular following of optokinetic stimulation. Eight healthy volunteers (of about 30 years of age) participated in three experiments. For each experiment, T2*-weighted single shot gradient echo EPI functional scans were acquired (TR/TE 3750/50ms, matrix size 64x64, slice thickness 4mm). The image data was processed with SPM-99 on both single-subject and group analysis level. In the first experiment, optokinetic eye movements were evoked by a random dot pattern with an infinite lifetime. In the second experiment, the optokinetic reflex was evoked by a random pattern of dots that had a limited lifetime (i.e., each dot was repositioned within 50 ms), which effectively excludes ocular following by smooth pursuit. As a control condition, smooth pursuit eye movements were evoked by a single dot in a third experiment. In each experiment a block design was used with three conditions of 30 seconds with 5 repetitions: the stimulus moved to ...

The vagus nerve plays an important role in both sensory and motor aspects of gastric physiology. Both animal and human studies suggest that accommodation reflex consists of a vagovagal reflex pathway. Thus, modulating vagal efference may be promising to...

Unknown onset time is a major contraindication to hyper acute ischaemic stroke treatment. If MRI could identify patients within the therapeutic time window or with enough salvageable tissue, many more patients would receive IV thrombolysis. Weighted MR ...