Search results for "Frontal Lobe"
showing 10 items of 158 documents
Grammatical distinctions in the left frontal cortex
2001
Abstract Selective deficits in producing verbs relative to nouns in speech are well documented in neuropsychology and have been associated with left hemisphere frontal cortical lesions resulting from stroke and other neurological disorders. The basis for these impairments is unresolved: Do they arise because of differences in the way grammatical categories of words are organized in the brain, or because of differences in the neural representation of actions and objects? We used repetitive transcranial magnetic stimulation (rTMS) to suppress the excitability of a portion of left prefrontal cortex and to assess its role in producing nouns and verbs. In one experiment subjects generated real w…
Amplitudes of laser evoked potential recorded from primary somatosensory, parasylvian and medial frontal cortex are graded with stimulus intensity
2003
Intensity encoding of painful stimuli in many brain regions has been suggested by imaging studies which cannot measure electrical activity of the brain directly. We have now examined the effect of laser stimulus intensity (three energy levels) on laser evoked potentials (LEPs) recorded directly from the human primary somatosensory (SI), parasylvian, and medial frontal cortical surfaces through subdural electrodes implanted for surgical treatment of medically intractable epilepsy. LEP N2* (early exogenous/stimulus-related potential) and LEP P2** (later endogenous potential) amplitudes were significantly related to the laser energy levels in all regions, although differences between regions w…
Prominence vs. aboutness in sequencing: a functional distinction within the left inferior frontal gyrus
2009
Prior research on the neural bases of syntactic comprehension suggests that activation in the left inferior frontal gyrus (lIFG) correlates with the processing of word order variations. However, there are inconsistencies with respect to the specific subregion within the IFG that is implicated by these findings: the pars opercularisor the pars triangularis. Here, we examined the hypothesis that the dissociation between parsopercularis and pars triangularis activation may reflect functional differences between clause-medial and clause-initial word order permutations, respectively. To this end, we directly compared clause-medial and clause-initial object-before-subject orders in German in a wi…
Word order and Broca’s region: Evidence for a supra-syntactic perspective
2008
It has often been suggested that the role of Broca's region in sentence comprehension can be explained with reference to general cognitive mechanisms (e.g. working memory, cognitive control). However, the (language-related) basis for such proposals is often restricted to findings on English. Here, we argue that an extension of the database to other languages can shed new light on the types of mechanisms that an adequate account of Broca's region should be equipped to deal with. This becomes most readily apparent in the domain of word order variations, which we examined in German verb-final sentences using event-related fMRI. Our results showed that activation in the pars opercularis--a core…
Beyond the amygdala: Linguistic threat modulates peri-sylvian semantic access cortices
2015
In this study, healthy volunteers were scanned using functional magnetic resonance imaging (fMRI) to investigate the neural systems involved in processing the threatening content conveyed via visually presented “threat words.” The neural responses elicited by these words were compared to those elicited by matched neutral control words. The results demonstrate that linguistic threat, when presented in written form, can selectively engage areas of lateral temporal and inferior frontal cortex, distinct from the core language areas implicated in aphasia. Additionally, linguistic threat modulates neural activity in visceral/emotional systems (amygdala, parahippocampal gyrus and periaqueductal gr…
Frontal–posterior theta oscillations reflect memory retrieval during sentence comprehension
2015
Abstract Successful working-memory retrieval requires that items be retained as distinct units. At the neural level, it has been shown that theta-band oscillatory power increases with the number of to-be-distinguished items during working-memory retrieval. Here we hypothesized that during sentence comprehension, verbal-working-memory retrieval demands lead to increased theta power over frontal cortex, supposedly supporting the distinction amongst stored items during verbal-working-memory retrieval. Also, synchronicity may increase between the frontal cortex and the posterior cortex, with the latter supposedly supporting item retention. We operationalized retrieval by using pronouns, which r…
Giant olfactory groove meningiomas: extent of frontal lobes damage and long-term outcome after the pterional approach.
2010
The treatment of giant olfactory groove meningiomas (OGMs; maximum diameter ≥ 6 cm) poses special problems and represents a surgical challenge. We discuss the long-term results in a series of 18 patients with giant OGMs and report our experience on a global strategy encompassing the pterional approach to manage the lesion and an extended transbasal approach to treat recurrences.Between February 1991 and December 2007, 18 patients with giant OGMs were surgically managed via a pterional craniotomy. Postoperative follow-up imaging was obtained at one, six, and 12 months and then yearly. In preoperative images, data from tumor volume were assessed. The volume of the residual right frontal poren…
Impaired control of an action after supplementary motor area lesion: A case study
2000
The kinematics of the action formed by reaching-grasping an object and placing it on a second target was studied in a patient who suffered from an acute vascular left brain lesion, which affected the Supplementary Motor Area proper (SMA-proper) (Matelli M, Luppino G. Thalamic input to mesial and superior area 6 in the macaque monkey. Journal of Comparative Neurology 1996;372:59-87, Matelli M, Luppino G, Fogassi L, Rizzolatti G. Thalamic input to inferior area 6 and area 4 in the macaque monkey. Journal of Comparative Neurology 1989;280:468-488), and in five healthy control subjects. The reach kinematics of the controls was affected by the positions of both the reaching-grasping and the plac…
Impairments in proverb interpretation following focal frontal lobe lesions.
2012
The proverb interpretation task (PIT) is often used in clinical settings to evaluate frontal “executive” dysfunction. However, only a relatively small number of studies have investigated the relationship between frontal lobe lesions and performance on the PIT. We compared 52 patients with unselected focal frontal lobe lesions with 52 closely matched healthy controls on a proverb interpretation task. Participants also completed a battery of neuropsychological tests, including a fluid intelligence task (Raven’s Advanced Progressive Matrices). Lesions were firstly analysed according to a standard left/right sub-division. Secondly, a finer-grained analysis compared the performance of patients w…
Brain abscess formation within an endodermal cyst of the frontal lobe: case report.
2009
A 38-year-old man with a right frontal lobe cyst was treated by endoscopic cystoventriculostomy in 1998. Cyst capsule histology revealed surprisingly an endodermal cyst. The patient was reoperated for cyst expansion by endoscopic re-cystoventriculostomy in 2005. In 2007, the patient suffered from brain abscess formation within the cyst which was punctured. The history was positive for a dental infection. In 2008, a recurrent brain abscess in the cyst occurred. The cyst was completely resected. There was no history of trauma or sinusitis. In all, endodermal cysts may mimic a paraxial arachnoid cyst. It may predispose for recurrent brain abscess formation - especially due to bacteraemia. This…