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Neuro-ophthalmology
Published in Mostafa Khalil, Omar Kouli, The Duke Elder Exam of Ophthalmology, 2019
The eye movements are under voluntary or reflex control. The voluntary movements are initiated in the frontal eye field (FEF), Brodmann area 8, in the frontal lobe. The reflex movements are coordinated via the occipital cortex and superior colliculus in response to a visual stimulus.
Discussions (D)
Published in Terence R. Anthoney, Neuroanatomy and the Neurologic Exam, 2017
Even though much of the orbital surface of the frontal lobe lies far anterior, making up most of Brodmann areas 11–12, some authors exclude the orbitofrontal cortex from their prefrontal area (e.g., prefrontal vs. limbic association cortex: K&S, p. 215, 674 (Table 51–11; DSR&W, p. 392). By reading the relevant material in the texts just cited, one sees that this exclusion results from data strongly linking the orbitofrontal cortex anatomically with the so-called limbic system. Such narrowing of the definition of prefrontal cortex, as a portion of it comes to be identified with a more specific anatomic-physiologic system, may represent a natural step in its semantic evolution. As might be anticipated when a term is defined in so many different ways, several authors are inconsistent in their usage. This is related particularly to the practice of assigning Brodmann-area designations to the prefrontal cortex. For example, Snell includes in his prefrontal cortex “the greater parts of the superior, middle, and inferior frontal gyri, the orbital gyri, most of the medial frontal gyrus, and the anterior half of the cingulate gyrus,” but he assigns to all of these only Brodmann areas 9–12 (1980, p. 264). There is a gross discrepancy here, for several additional areas (at least 24, 32–33, and 46–47) are included in the gyri he describes. Similarly, Gilman and Newman describe the “prefrontal region” as consisting of “The large remaining part of the frontal lobe lying rostral to the motor and premotor areas,” but they, too, assign to that region only Brodmann areas 9–12 (1987, p. 208).The most inconsistencies I noted are in a textbook by Noback and Demarest (1981). Their broadest definition of the “prefrontal cortex” is “The portion of the frontal lobe located rostral to the precentral sulcus” (p. 5). In other words, it would correspond closely to Brodmann areas 6, 8–12, 32, and 44 47; but it would not include areas 24 and 33, since the latter are in the cingulate gyrus, which Noback and Demarest define as being outside the frontal lobe (in the separate “limbic lobe”—e.g., p. 8 [including Fig. 1–8], 473). On p. 12, however, they define the prefrontal cortex more narrowly, excluding the “premotor area”—i.e., Brodmann areas 6, 44, and 45 (see, also, p. 2 [Fig. 1–2]). A third and even narrower definition of prefrontal cortex is used on p. 473, 511, and 515, where Noback and Demarest exclude not only Brodmann areas 6 and 44 45. but also Brodmann area 85 and the “orbitofrontal cortex” (which they equate with Brodmann areas 11–12, p. 511). In this definition, they also explicitly include Brodmann area 24 (p. 473, 515). This is inconsistent with their statements that the prefrontal cortex is part of the frontal lobe (e.g., p. 5, 12, 511), for area 24 lies wholly within the limbic lobe, which Noback and Demarest define as separate from the frontal, parietal, temporal, and occipital lobes (p. 8 [including Fig. 1–8]).
Brain regions associated with olfactory dysfunction in first episode psychosis patients
Published in The World Journal of Biological Psychiatry, 2023
Semra Etyemez, Zui Narita, Marina Mihaljevic, Jennifer M. Coughlin, Gerald Nestadt, Frederick C. Jr. Nucifora, Thomas W. Sedlak, Nicola G. Cascella, Finn-Davis Batt, Jun Hua, Andreia Faria, Koko Ishizuka, Vidyulata Kamath, Kun Yang, Akira Sawa
The SFG corresponds to Brodmann area 8 (BA8) and partially to BA6 in the present segmentation (Figure S1). The unique involvement of this specific brain area in SZ patients with primary negative symptoms has been underscored and particularly a reduction in grey matter volume in SFG has been reported (Cascella et al. 2010; Leung et al. 2011). We now provide novel evidence that indicates the relation of SFG with olfactory function in FEP patients. The SFG region is described to be involved in self-awareness and emotion (Fried et al. 1998; Goldberg et al. 2006). Self-awareness is defined as the cognitive ability to distinguish between the self and others and broadly requires the use of perception, recognition, and differentiation. These cognitive processes (self-awareness and social cognition) are similar to those required in odour discrimination task, requiring perception, recognition, and differentiation. Although there are many other ways of interpretation, we provocatively state that our finding of olfactory dysfunction associated with SFG might have a relationship with self-awareness and related brain function. Further studies are warranted.
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
Arterial Spin Labeling (ASL) is a relatively new brain imaging modality in the field of psychiatry. ASL is utilized to quantify brain tissue perfusion by using labeled arterial blood as an endogenous tracer [16]. The ASL method was reported to induce less across-subject variability and long-term reproducibility [17,18]. Moreover, when compared to functional magnetic resonance imaging (fMRI), ASL was shown to be more sensitive to the tonic changes – rather than phasic responses – of brain metabolism to a given cognitive task [17,19,20]. However, there are studies resulted with tonic blood flow changes in minutes during a given cognitive task and slow continuous changes can be detected in ASL imaging [9,21–23]. To date, few ASL findings relating to the attention system have been published. Increased rCBF during the resting state ASL scan was found in the left caudate, inferior/medial frontal gyrus and bilateral cingulate gyrus and precuneus in adult subjects with ADHD relative to controls [24]. Further, increased rCBF in the right-sided frontoparietal areas including medial (BA8, 9) and inferior frontal gyrus, occipital gyri (BA18), bilateral anterior cingulate (BA32) was reported in several ASL studies utilizing with sustained attention and vigilance tasks [9,21,22]. However, these prior studies were conducted on adults and most did not include ADHD subjects. To the best of our knowledge, this is the first event-related ASL study comparing children with ADHD and control subjects in the literature.
When cooperation goes wrong: brain and behavioural correlates of ineffective joint strategies in dyads
Published in International Journal of Neuroscience, 2018
Michela Balconi, Laura Gatti, Maria Elide Vanutelli
fNIRS recordings were conducted with NIRScout System (NIRx Medical Technologies, LLC. Los Angeles, CA) using an eight-channel array of optodes (four light sources/emitters and four detectors) covering the prefrontal area. Emitters were placed on positions FC3–FC4 and F1–F2, while detectors were placed on FC1–FC2 and F3–F4 (Figure 2). Emitter–detector distance was kept at 30 mm for contiguous optodes and near-infrared light of two wavelengths (760 and 850 nm) were used. NIRS optodes were placed on the subject's head using an NIRS-EEG compatible cup according to the international 10/5 system. Resulting channels were as follows: Ch 1 (FC3–F3) and Ch 3 (FC4–F4) correspond to the left and right (respectively) DLPFC (Brodmann Area 9). Ch 2 (FC3–FC1) and Ch 4 (FC4–FC2) correspond to the left and right (respectively) Premotor Cortex (Brodmann Area 6). Ch 5 (F1–F3) and Ch 7 (F2–F4) correspond to the left and right (respectively) Frontal Eye Fields (FEF, Brodmann Area 8). Ch 6 (F1–FC1) and Ch 8 (F2–FC2) correspond to the left and right (respectively) SFG (Brodmann Area 6) [35].