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Neuroimaging
Published in John O'Brien, Ian McKeith, David Ames, Edmond Chiu, Dementia with Lewy Bodies and Parkinson's Disease Dementia, 2005
There have been several studies investigating PET and SPECT changes in DLB. PET studies of glucose metabolism and SPECT investigations using blood flow markers such as 99mTc-HMPAO have demonstrated many similarities to the patterns seen in AD (Donnemiller et al, 1997; Varma et al, 1997; Defebvre et al, 1999; Ishii et al, 1999; Lobotesis et al, 2001; Minoshima et al, 2001). Pronounced biparietal hypoperfusion is seen, together with variable deficits in frontal and temporal lobes, which again are usually symmetric. Bilateral parietal hypoperfusion in DLB is even more extensive than in AD cases matched for age and dementia severity (Colloby et al, 2002), particularly in Brodmann area 7, an area that mediates important aspects of visuospatial function. Pronounced hypoperfusion in this area may underpin the pronounced visuospatial impairments characteristic of DLB, although further studies correlating imaging changes with detailed neuropsychology are required.
Increased cerebral blood flow in the right anterior cingulate cortex and fronto-orbital cortex during go/no-go task in children with ADHD
Published in Nordic Journal of Psychiatry, 2021
Muharrem Burak Baytunca, Blaise de Frederick, Gul Unsel Bolat, Burcu Kardas, Sevim Berrin Inci, Melis Ipci, Cem Calli, Onur Özyurt, Dost Öngür, Serkan Süren, Eyüp Sabri Ercan
We identified three right-sided core clusters in the superior parietal lobe (BA7), middle/inferior frontal gyrus, and temporoparietal areas – including the posterior transverse temporal lobule (BA42), inferior parietal lobule (BA40) and supramarginal gyrus – in children with ADHD during the go session. It should be cautiously noted that the two latter clusters are within the ventral attention network. The ventral network consists of the TPJ (at the intersection of the posterior side of the superior temporal gyrus, inferior parietal lobule, and lateral occipital cortex), the ventral parts of supramarginal gyrus and middle/inferior frontal gyrus, as well as the frontal operculum and anterior insula. The ventral attention network is activated along with the dorsal attention network when a behaviorally relevant stimulus is presented [11,14]. In a visual sustained attention task-integrated ASL study, researchers have reported greater activation in the right middle frontal gyrus (BA8,9) bilateral occipital gyrus (BA18), right cuneus (BA18) and the left cingulate gyrus (BA32) when compared to the resting state in adults [9]. Additionally, a significant rCBF increase was reported in the right middle/inferior frontal gyrus, right inferior parietal lobe, bilateral supplementary motor area/anterior cingulate cortex, bilateral basal ganglia/insula and the left sensorimotor cortex during a sustained attention task in an ASL study.
‘Eppur si move’: The Association Between Electrophysiological and Psychophysical Signatures of Perceived Movement Illusions
Published in Journal of Motor Behavior, 2018
Michela Balconi, Davide Crivelli, Marco Bove
By focusing on psychophysical features of motor illusion experiences, we observed that stronger illusions are overall consistently perceived and estimated as longer lasting and that a greater sensitivity to illusory perceptions (i.e., more frequent perceptions) was associated to more vivid and longer illusions on average. The correlations we observed between different psychophysical measures, besides underlining the internal consistency of the aware experiences we induced and investigated, are in line with our hypotheses and previous literature on phenomenological features of movement illusions (see Naito et al., 1999). More generally, as underlined by Metzinger (2003), human self-consciousness and conscious experiences are characterized by at least three primary and necessary basic aspects: feeling of ownership (and often agency), first-person perspective, and—of particular relevance for this discussion—unity. Unified and integrated perceptions and representations, thus, constitute our aware experience of reality and the actual entrance of a perceptual experience in the consciousness domain depends on subjective thresholds, defined as individual propensity to consciously detect and process them. Consistently, and for the first time to our knowledge, we report that such relevant aspect of the illusory experience (i.e., individual frequency of illusory perceptions) proved to be specifically associated to the degree of estimated cortical activity of contralateral superior-medial parietal areas (BA5, BA7, BA31). In particular, psychophysical and neurofunctional data were inversely correlated (i.e., contralateral parietal structures tended to activate less as the frequency of motor illusions increased).
Unisensory and multisensory Self-referential stimulation of the lower limb: An exploratory fMRI study on healthy subjects
Published in Physiotherapy Theory and Practice, 2018
Ana Isabel Vieira, Patrícia Almeida, Nádia Canário, Miguel Castelo-Branco, Maria Vânia Nunes, Alexandre Castro-Caldas
Some authors support the existence of a brain network comprising a few of the regions also found in our experience such as the medial prefrontal cortex (BA9), precuneus (BA7), posterior cingulate gyrus (BA30), and TPJ (Ciavarro et al. 2012; Ruby and Legrand 2007). Nevertheless, Ruby and Legrand (2007) stated that these brain network cannot be considered Self-specific because the activation of the regions that form the network could be explained also by the reasoning involved in the evaluation of the sensory inputs using the information stored in memory. They also argued that sensorimotor integration may also play an important role in the construction of the Self.