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Cortical Visual Loss
Published in Vivek Lal, A Clinical Approach to Neuro-Ophthalmic Disorders, 2023
Simultanagnosia has been linked to lesions of the dorsal occipital lobes, in Brodmann's areas 18 and 19 (384). There can also be contributions from damage to other components of a visual attention network, such as the middle frontal gyrus and white matter connections in the inferior and superior longitudinal fasciculi (390).
Preparing the Patient for the fMRI Study and Optimization of Paradigm Selection and Delivery
Published in Andrei I. Holodny, Functional Neuroimaging, 2019
Lastly, if the fMRI is being ordered for neurosurgical planning, it is important to consider the neurosurgeon’s goals and to tailor the paradigms to these specific goals. The most basic decision that the neurosurgeon must undertake is weather or not to attempt a resection. If it can be demonstrated that the lesion is located in an essential, eloquent cortex, the neurosurgeon may decide to forego an attempted resection and biopsy the lesion. For example, it may be difficult to tell, whether a lesion is located in the precentral gyrus or within the posteriormost aspect of the middle frontal gyrus. If the fMRI demonstrates the former, the neurosurgeon may settle for a biopsy, whereas, if the fMRI demonstrates the latter, the neurosurgeon may decide on a resection.
Neuroimaging studies of individuals with Down syndrome
Published in Vee P. Prasher, Down Syndrome and Alzheimer’s Disease, 2018
Felix Beacher, Declan G. M. Murphy
A recent MRI study of non-demented subjects with DS reported that cross-sectional area of the corpus callosum was significantly positively correlated with overall cognitive function as measured by the Peabody Picture Vocabulary Test, Revised.60 Corpus callosum atrophy is proposed to be a marker of neocortical atrophy in the AD brain.61 Teipel and colleagues62 therefore inferred that callosal atrophy may indicate more general neocortical atrophy in non-demented individuals with DS. VBM analysis of the same data showed significant correlations between memory performance (but not overall cognitive ability) and grey matter volume of the left superior and middle temporal gyrus, bilateral precuneus, left hippocampus, right middle temporal gyrus and right middle frontal gyrus.63 Thus the biological validity of the reported correlations between overall cognitive function and cross-sectional area of the corpus callosum is probably low.
The influence of hormonal contraception on depression and female sexuality: a narrative review of the literature
Published in Gynecological Endocrinology, 2022
Laura Buggio, Giussy Barbara, Federica Facchin, Laura Ghezzi, Dhouha Dridi, Paolo Vercellini
In the brain, sex steroids regulate arousal, appetite and reproductive behavior [10]. Emotional processing and cognitive function are influenced by the changes in the levels of estrogens and progestogens during the menstrual cycle [11]. Functional imaging studies have shown how the degree of activation of brain areas involved in these processes differs during the different phases of the cycle [11]. Unfortunately, there is little consistency across all the studies that are also very heterogeneous in terms of the study population, outcomes and techniques used [11]. In general, increased activation of the amygdala, insula, cingulate gyrus, hippocampus, prefrontal and orbitofrontal cortex is reported in response to visualization or retrieval of negative pictures during the follicular phase compared to the luteal [12–14]. These brain areas are all involved in the emotional processing and/or response to negative stimuli [15]. A similar increase in the activation has been observed in areas involved in cognitive processes, during the early and mid-follicular phases compared to late follicular phases, and during the late follicular compared to the mid-luteal phase. The precuneus, medial temporal gyrus, medial orbitofrontal cortex and hippocampus showed increased activation during response inhibition and verbal memory tasks [16,17]. The fusiform gyrus resulted more activated during spatial recognition tasks [18] and the inferior and middle frontal gyrus during verbal memory and semantic retrieval [19,20].
Apathetic symptoms and white matter integrity after traumatic brain injury
Published in Brain Injury, 2021
B Navarro-Main, AM Castaño-León, A Hilario, A Lagares, G Rubio, JA Periañez, M Rios-Lago
Behaviour-AES-I and Cognitive-AES-I groups of items did not showed any negative correlations with FA values. However, both showed some areas of positive correlations with FA. Positive correlations between cognitive-AES-I and FA values appeared in bilateral superior parietal lobule, right superior frontal gyrus, bilateral angular gyrus, left cuneus and right precunneus, inferior occipitotemporal regions in left hemisphere predominantly, bilateral precentral and postcentral gyrus, and right amygdala. Positive correlations between behaviour-AES-I and FA were obtained in right cortical regions as precunneus, angular gyrus, superior frontal gyrus, and middle temporal gyrus. In left hemisphere positive relationships were found with precentral gyrus and thalamus. Emotional-AES-I and the Other-AES-I groups of items show both positive and negative significant correlation with FA values. Firstly, negative correlations of FA and emotional items values were found in the right inferior longitudinal fasciculus (ILF), right SLF and left middle temporal gyrus white matter. In the group of items named as Other-AES-I negative correlation with FA values were found in the left posterior limb of internal capsule. Positive correlations were found in the emotional group in right cingulate gyrus and left middle frontal gyrus white matter. Positive correlations were identified, between FA and Other-AES-I score, in the right middle frontal gyrus, right cingulate gyrus and left middle occipital gyrus.
Evaluation of Memory and Language Network in Children and Adolescents with Visual Impairment: A Combined Functional Connectivity and Voxel-based Morphometry Study
Published in Neuro-Ophthalmology, 2021
A Ankeeta, Rohit Saxena, S Senthil Kumaran, Sada Nand Dwivedi, Naranamangalam Raghunathan Jagannathan, Vaishna Narang
Activation of the cingulate sulcus and supplementary motor areas in both of these groups may be attributed to cognition, verb generation, attention and motor behaviour corresponding to their role in Braille reading and semantic retrieval.11,31,43 Activations in the prefrontal area, middle frontal gyrus (BA 9, 46) and inferior frontal gyrus (BA 45,47) in blind participants is indicative of word retrieval through the dorsal pathway with tactile and semantic encoding tasks44 and object naming31 associated with semantic language processes. Shifting of inferior frontal gyrus and increased BOLD responses in LB and EB adolescents may be due to lateralisation of the language areas. All participants may have been encoding the noun words (concrete or abstract nouns) into some object category followed by semantic processing. FC in EB and LB participants showed an increased range of connectivity with the hippocampus to language areas revealing the processing of Braille semantic and lexical components. The lateralisation of language processing is left lateralised and there is no change in this process.44