MEG activity of the dorsolateral prefrontal cortex during optic flow stimulations detects mild cognitive impairment due to Alzheimer’s disease

Dorsal stream, which has a neuronal connection with dorsolateral prefrontal cortex (DLPFC), is known to be responsible for detection of motion including optic flow perception. Using magnetoencephalography (MEG), this study aimed to examine neural responses to optic flow stimuli with looming motion in the DLPFC in patients with mild cognitive impairment due to Alzheimer’s disease (AD-MCI) compared with cognitively unimpaired participants (CU). We analyzed the neural responses by evaluating maximum source-localized power for the AD-MCI group (n = 11) and CU (n = 20), focusing on six regions of interest (ROIs) that form the DLPFC: right and left dorsal Brodmann area 9/46 (A9/46d), Brodmann area 46 (A46) and ventral Brodmann area 9/46 (A9/46v). We found significant differences in the maximum power between the groups in the left A46 and A9/46v. Moreover, in the left A9/46v, the maximum power significantly correlated with the Wechsler Memory Scale-Revised general memory score and delayed recall score. The maximum power in the left A9/46v also revealed high performance in AD-MCI versus CU classification with the area under the ROC curve of 0.90. This study demonstrated that MEG during the optic flow task can be useful in discriminating AD-MCI from CU.

P03.06 Boolean logic puzzles as a neurosurgical mapping tool to preserve programming skill

BACKGROUND In glioma surgery, awake craniotomy with Direct Electrical Stimulation (DES) is increasingly becoming the gold standard treatment to preserve language, cognition and motor function and to optimize extent of resection. Computer programming is historically seen as an integration of cognition, language, and mathematics but an intraoperative task to monitor computer programming does not exist yet. In this study we describe a new task for intraoperative monitoring, using visual Boolean Logic Puzzles. MATERIAL AND METHODS We describe a computer programmer who underwent awake craniotomy to resect an anaplastic astrocytoma in the left superior frontal gyrus. At the request of the patient we tested programming language. We developed a new task and set of logic puzzle visual stimuli to monitor underlying cognitive function used for programming language. This test was used during preoperative functional MRI (fMRI), direct electrical stimulation (DES) and ongoing monitoring during resection. RESULTS In fMRI this task showed bilateral activation in Brodmann area 6 and 8 and for left hemisphere in Brodmann area 10. These areas are below and lateral of the tumor. Monitoring of language, motor skills and Boolean mapping was performed during DES and while resection was performed. No deficits in programming ability could be identified intra- and postoperatively. CONCLUSION Boolean Logic Puzzles may be a useful intraoperative task to preserve programming skills.

Mirror Mechanism Behind Visual–Auditory Interaction: Evidence From Event-Related Potentials in Children With Cochlear Implants

The mechanism underlying visual-induced auditory interaction is still under discussion. Here, we provide evidence that the mirror mechanism underlies visual–auditory interactions. In this study, visual stimuli were divided into two major groups—mirror stimuli that were able to activate mirror neurons and non-mirror stimuli that were not able to activate mirror neurons. The two groups were further divided into six subgroups as follows: visual speech-related mirror stimuli, visual speech-irrelevant mirror stimuli, and non-mirror stimuli with four different luminance levels. Participants were 25 children with cochlear implants (CIs) who underwent an event-related potential (ERP) and speech recognition task. The main results were as follows: (1) there were significant differences in P1, N1, and P2 ERPs between mirror stimuli and non-mirror stimuli; (2) these ERP differences between mirror and non-mirror stimuli were partly driven by Brodmann areas 41 and 42 in the superior temporal gyrus; (3) ERP component differences between visual speech-related mirror and non-mirror stimuli were partly driven by Brodmann area 39 (visual speech area), which was not observed when comparing the visual speech-irrelevant stimulus and non-mirror groups; and (4) ERPs evoked by visual speech-related mirror stimuli had more components correlated with speech recognition than ERPs evoked by non-mirror stimuli, while ERPs evoked by speech-irrelevant mirror stimuli were not significantly different to those induced by the non-mirror stimuli. These results indicate the following: (1) mirror and non-mirror stimuli differ in their associated neural activation; (2) the visual–auditory interaction possibly led to ERP differences, as Brodmann areas 41 and 42 constitute the primary auditory cortex; (3) mirror neurons could be responsible for the ERP differences, considering that Brodmann area 39 is associated with processing information about speech-related mirror stimuli; and (4) ERPs evoked by visual speech-related mirror stimuli could better reflect speech recognition ability. These results support the hypothesis that a mirror mechanism underlies visual–auditory interactions.

Study of Extra-visual Resting-state Networks in Pituitary Adenoma Patients With Vision Restoration

Background: Pituitary adenoma(PA) may compress the optic apparatus and cause impaired vision. Some patients can get improved vision rapidly after surgery. During the early time after surgery, however, the change of neurofunction in extra-visual cortex and higher cognitive cortex is still yet to be explored so far. Objective: Our study is focused on the changes in the extra-visual resting-state networks in PA patients after vision restoration. Methods:We recruited 14 PA patients with visual improvement after surgery. The functional connectivity (FC) of 6 seeds (auditory cortex (A1), Broca's area, posterior cingulate cortex (PCC)for default mode network (DMN), right caudal anterior cingulate cortex for salience network(SN) and left dorsolateral prefrontal cortex for excecutive control network (ECN)) were evaluated. A paired t-test was conducted to identify the differences between two groups. Results: Compared with the preoperation counterparts, the PA patients with improved vision exhibited decreased FC with right A1 was identified in left insula lobule, right middle temporal gyrus and left postcentral gyrus, and increased FC in the right paracentral lobule; decreased FC with broca in left middle temporal gyrus, and increased FC in left Insula lobule and right thalamus; decreased FC with DMN in right declive, and right precuneus, and increased FC in right brodmann area 17, left cuneus and right posterior cingulate; decreased FC with ECN in right posterior cingulate, right angular and right precuneus; decreased FC with SN in right middle temporal gyrus, right hippocampus, and right precuneus, and increased FC in right fusiform gyrus, left lingual gyrus and right brodmann area 19.Conclusions: The vision restoration may cause the response of cross-modal plasticity and the multisensory system related to A1 and broca. The DMN and SN may involve in top-down control on the subareas within vision cortex. The precuneus may involve in DMN, ECN and SN simultaneously.

Comparison of Neural Activation Area in Primary Somatosensory Cortex and Brodmann Area 3 According to Finger and Phalange High-Frequency Vibration Stimulation

In this study, we measured neuronal activation in the primary somatosensory area (S1) and Brodmann area 3 (BA3) using 3T functional magnetic resonance imaging (fMRI) while presenting a 250-Hz high-frequency vibrational stimulus to each of three phalanges (distal, intermediate, and proximal) of four fingers of the right hand (index, middle, ring, and little). We compared the nerve activation area between each finger and each phalange. Ten healthy male college students (26.6 ± 2.5 years old) participated in this study. One session consisted of three blocks: a rest (30 s), stimulation (30 s), and response phase (9 s). In the rest phase, the vibrational stimulus was not presented. In the stimulation phase, the vibrational stimulation was presented at any one of the three phalanges of the selected finger. In the response phase, subjects were instructed to press a button corresponding to the phalange that they thought had received the vibration. The subtraction method was used to extract the activation area. The activation area in the S1 was the largest when the little finger was stimulated (for the finger comparison), and largest when the second phalange was stimulated (for the phalange comparison). The BA3 showed similar trends, and there was no statistically significant difference.

Severe apathy due to injury of prefronto-caudate tract

The caudate nucleus, which is vulnerable to hypoxic–ischemic brain injury (HI-BI), is important to cognitive function because it is connected to the prefrontal cortex. Using diffusion tensor tractography (DTT), no study on injury of the prefronto-caudate tract in a patient with HI-BI has been reported so far. Here, we report a patient with severe apathy who showed injury of the prefronto-caudate tract following HI-BI, which was demonstrated by DTT. A 38-year-old female patient suffered HI-BI induced by carbon monoxide poisoning following attempted suicide for a period of approximately four hours. From the onset, the patient showed severe apathy (7 months after onset-the Apathy Scale score was 24 [full score: 42]). Brain MR images taken at seven months after onset showed no abnormality. On 7-month DTT, the neural connectivity of the caudate nucleus to the medial prefrontal cortex (Brodmann area: 10 and 12) and orbitofrontal cortex (Brodmann area: 11 and 13) was decreased in both hemispheres. Using DTT, injury of the prefronto-caudate tract was demonstrated in a patient who showed severe apathy following HI-BI. We believe that injury of the prefronto-caudate tract might be a pathogenetic mechanism of apathy in patients with HI-BI.