Activation In Left Temporal Regions Research Articles

Morphological processing in Chinese engages left temporal regions

Morphological awareness, the ability to manipulate the smallest units of meaning, is critical for Chinese literacy. This is because Chinese characters typically reflect the morphemic, or morpho-syllabic units of language. Yet, the neurocognitive mechanisms underlying Chinese speakers’ morphological processing remain understudied. Proficient readers (N = 14) completed morphological and phonological judgment tasks in Chinese, in both auditory and visual modalities, during fMRI imaging. Key to our inquiry were patterns of activation in left temporal regions, especially the superior temporal gyrus, which is critical for phonological processing and reading success. The findings revealed that morphological tasks elicited robust activation in superior and middle temporal regions commonly associated with automated phonological and lexico-semantic analyses. In contrast, the rhyme judgment task elicited greater activation in left frontal lobe regions, reflecting the analytical complexity of sound-to-print mapping in Chinese. The findings suggest that left temporal regions are sensitive to salient morpho-syllabic characteristics of a given language.

The ConDialInt Model: Condensation, Dialogality, and Intentionality Dimensions of Inner Speech Within a Hierarchical Predictive Control Framework.

Inner speech has been shown to vary in form along several dimensions. Along condensation, condensed inner speech forms have been described, that are supposed to be deprived of acoustic, phonological and even syntactic qualities. Expanded forms, on the other extreme, display articulatory and auditory properties. Along dialogality, inner speech can be monologal, when we engage in internal soliloquy, or dialogal, when we recall past conversations or imagine future dialogs involving our own voice as well as that of others addressing us. Along intentionality, it can be intentional (when we deliberately rehearse material in short-term memory) or it can arise unintentionally (during mind wandering). We introduce the ConDialInt model, a neurocognitive predictive control model of inner speech that accounts for its varieties along these three dimensions. ConDialInt spells out the condensation dimension by including inhibitory control at the conceptualization, formulation or articulatory planning stage. It accounts for dialogality, by assuming internal model adaptations and by speculating on neural processes underlying perspective switching. It explains the differences between intentional and spontaneous varieties in terms of monitoring. We present an fMRI study in which we probed varieties of inner speech along dialogality and intentionality, to examine the validity of the neuroanatomical correlates posited in ConDialInt. Condensation was also informally tackled. Our data support the hypothesis that expanded inner speech recruits speech production processes down to articulatory planning, resulting in a predicted signal, the inner voice, with auditory qualities. Along dialogality, covertly using an avatar’s voice resulted in the activation of right hemisphere homologs of the regions involved in internal own-voice soliloquy and in reduced cerebellar activation, consistent with internal model adaptation. Switching from first-person to third-person perspective resulted in activations in precuneus and parietal lobules. Along intentionality, compared with intentional inner speech, mind wandering with inner speech episodes was associated with greater bilateral inferior frontal activation and decreased activation in left temporal regions. This is consistent with the reported subjective evanescence and presumably reflects condensation processes. Our results provide neuroanatomical evidence compatible with predictive control and in favor of the assumptions made in the ConDialInt model.

Small temporal pole encephaloceles in children with presumed nonlesional temporal lobe epilepsy

Objective: Temporal lobe epilepsy (TLE) is the one of most common form of focal epilepsy. Children with intractable TLE epilepsy undergo presurgical evaluations for resective treatment. The cases are considered “nonlesional’’ if brain magnetic resonance imaging (MRI) shows no structural abnormality and they sometimes encounter invasive procedures. We describe two patients, initially thought to have “lesion negative” refractory TLE, in whom the recognition of a small anterior temporal encephalocele by close inspection of imaging altered the follow up strategy. Case Presentation: Case 1: 12-year-old girl, focal seizures began at age 10 years, manifesting as no reduced awareness, contractions in the corner of the mouth, and head version. At the time of assessment the patient was having multiple daily attacks. Two antiepileptic drugs in various doses and combinations had failed to control seizures. Early childhood development and schooling were unremarkable. Febrile seizures had not occurred. Video–electroencephalography (EEG) monitoring captured ten typical seizures, all originating from the right temporal region. Prior imaging was reported normal. The current brain MRI has showed small right anterior temporal tip encephalocele through a congenital defect in the sphenoidal bone. She is now a epilepsy surgery candidate. Case 1: 15-year-old girl, discognitive seizures began at age 6 years characterized by a rising abdominal sensation and impaired consciousness. Seizures continued weekly with no evolving to bilateral convulsive seizures, despite trials of two anticonvulsants in various doses and combinations. Febrile seizures had not occurred. Routine EEG showed interictal epileptiform activity in left temporal region. Prior imaging was reported normal. The current brain MRI has showed bilateral temporal tip encephalocele greater on the left. She will be hospitalized for phase I epilepsy surgery evaluations. Conclusion: We would like to present this cases to emphasize the discovery of an occult lesion such as an encephalocele markedly alters treatment opinions in children.

Left Temporal Neuronal Hyperexitability as a Predictor of Mild Cognitive Impairment: Clinical and Neurophysiological Study

Introduction: Mild cognitive impairment (MCI) usually is the early stage of dementia which is defined as decreasing in mental abilities such cognition, memory, and speech not too severe to interfere daily activities. MCI diagnosis is rather hard and usually assumed as normal consequences of aging. Diagnosis is usually performed through a combination of extensive testing and eliminations of other possible causes. “Seizures” or neuronal hyperexitability in the temporal lobe, transiently impair cognition and steadily damage hippocampal circuitry, leading to progressive memory loss. Objective: The objective of this study was demonstrated that EEG pattern abnormalities in the left temporal in healthy subjects, are an early sign of progressive cognitive impairment. Material and methods: This was an clinical and neurophysiology observational study in healthy adults patients with EEG pattern characterized by slow activity in left temporal region. This study lasted three years in total, being divided into two phases: recruitment (for an entire year) and follow-up after 1 year. Admission criteria were checked. The follow-up consisted of neuropsychological assessment with Mini Mental State Examination (MMSE) and MRI scan. Our analysis was based on pooled of patients from neurophysiology department in Italy from February 2010 to July 2013. The EEG activity was recorded continuously from 19 electrodes positioned according to the 10–20 International system. Results: One hundred forty patients were recruited and one hundred thirty completed the 24-month study. Of the ten patients who did not complete the study. In case group we had 60 subjects, 15 males and 45 females with sharp slow-wave in left temporal region on EEG. In control group we had 70 subjects, 30 males and 40 females with normal EEG. 57 patients (Case) and 33 patients (Controls) showed a mild cognitive impairment (MMSE ≥ 23 adjusted for age and education). 49 patients (Case) and 21 patients (Controls) with deep lacunar infarcts or subcortical white matter alterations on MRI scan. Analysis performed according to methods proposed by Koch showed that pattern EEG of slow waves significantly correlated with both variables MCI (P<0.0001) and vascular alterations (P<0.0001). Discussion: In our sample, pattern EEG was predictive for vascular abnormalities and MCI more than 50% after a few years. Conclusion: In summary, typical geographic alterations in left temporal region are “indicators” or “markers” of early cognitive impairment and may be used as prevention strategies. EEG may be considered a useful tool for early diagnosis of MCI. Further translational exploration of these issues in animals and/or humans studies over the coming years will determine new therapeutic approaches directed at selectively suppressing aberrant network excitability in the temporal lobe.

7. EEG findings in three patients with Alternating Hemiplegia of childhood (AHC)

Aim First reported by Verret and Steele in 1971, Alternating hemiplegia of childhood (AHC) is a rare disorder. The incidence is reported at 1 in 1,000,000 but this is most likely higher as AHC is often misdiagnosed. Infants often present with recurrent attacks of hemiplegia affecting either side of the body, abnormalities of ocular movement, movement disorders, and progressive developmental delay. It has been reported to be associated with mutations in CACNA1A, a calcium channel gene, and ATP1A2, a sodium potassium ATPase gene. It has been reported in large cohort studies that close to 50% of children with AHC will develop epilepsy. The purpose of this study is to examine the EEG finding with patient with AHC to further help clarify diagnosis. Methods This paper will explore 3 patients, chart review, with confirmed genetic testing of the APT1A2 gene mutation, EEG findings. Results Patient 1(R.G) low background activity in left temporal region, irregular sharp slow ave complex at 2 Hz, mild epileptiform focus in right posterior T6, T4 (temporal region. Patient 2 (A.K). slow wave at 4 Hz over both hemispheres that progressed to vertex waves and hypnagogic hypersynchrony after gamma hydroxbutyrate administration. Patient 3 (A.B), normal EEG. Summary Although the findings seen in patient with AHC are not pathognomonic, EEG is still a powerful tool in diagnosing patients especially in situations where genetic testing is not available.

Electroencephalography as a Tool for Assessment of Brain Ischemic Alterations after Open Heart Operations

Cardiac surgery is commonly associated with brain ischemia. Few studies addressed brain electric activity changes after on-pump operations. Eyes closed EEG was performed in 22 patients (mean age: 45.2 ± 11.2) before and two weeks after valve replacement. Spouses of patients were invited to participate as controls. Generalized increase of beta power most prominent in beta-1 band was an unambiguous pathological sign of postoperative cortex dysfunction, probably, manifesting due to gamma-activity slowing (“beta buzz” symptom). Generalized postoperative increase of delta-1 mean frequency along with increase of slow-wave activity in right posterior region may be hypothesized to be a consequence of intraoperative ischemia as well. At the same time, significant changes of alpha activity were observed in both patient and control groups, and, therefore, may be considered as physiological. Unexpectedly, controls showed prominent increase of electric activity in left temporal region whereas patients were deficient in left hemisphere activity in comparison with controls at postoperative followup. Further research is needed in order to determine the true neurological meaning of the EEG findings after on-pump operations.

EEG findings in senile dementia and normal aging.

EEG findings in 62 patients with senile dementia of alzheimer type (SDA), 22 patients with multi-infarct dementia (MID) and 90 controls of same age and sex were studied. The SDA patients differed significantly from the controls in EEG normality, over-all disturbance, dominant occipital, rhythm, accentuation of theta and delta, fluctuations in alertness, paroxysmal activity and H-reaction. Even the least severely affected SDA patients differed significantly from the controls in all EEG variables except paroxysmal activity. With increasing degree intellectual impairment in the SDA group the dominant occipital rhythm became slower. The MID group differed from the controls in all EEG parameters including asymmetric findings. The EEG findings of the SDA patients differed significantly from those of the MID patients only in asymmetric findings which were more common in the MID patients. 29% of the normal elderly people had EEG alterations, Abnormalities were mild. Asymmetric findings, mainly theta activity in left temporal region were common. H-reaction (occipital driving response greater than or equal to 18 c/s) was well preserved in the controls. EEG is valuable in differentiation of dementia patients from normal elderly people, but differentiation between MID and SDA is not reliable by using EEG, only.