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Brain Structure & Function Jan 2023Traditional and new disciplines converge in suggesting that the parietal lobe underwent a considerable expansion during human evolution. Through the study of endocasts... (Review)
Review
Traditional and new disciplines converge in suggesting that the parietal lobe underwent a considerable expansion during human evolution. Through the study of endocasts and shape analysis, paleoneurology has shown an increased globularity of the braincase and bulging of the parietal region in modern humans, as compared to other human species, including Neandertals. Cortical complexity increased in both the superior and inferior parietal lobules. Emerging fields bridging archaeology and neuroscience supply further evidence of the involvement of the parietal cortex in human-specific behaviors related to visuospatial capacity, technological integration, self-awareness, numerosity, mathematical reasoning and language. Here, we complement these inferences on the parietal lobe evolution, with results from more classical neuroscience disciplines, such as behavioral neurophysiology, functional neuroimaging, and brain lesions; and apply these to define the neural substrates and the role of the parietal lobes in the emergence of functions at the core of material culture, such as tool-making, tool use and constructional abilities.
Topics: Humans; Anthropology, Cultural; Biological Evolution; Parietal Lobe; Skull
PubMed: 35451642
DOI: 10.1007/s00429-022-02487-w -
Brain, Behavior and Evolution 2018Paleoneurology deals with the study of brain anatomy in fossil species, as inferred from the morphology of their endocranial features. When compared with other living... (Review)
Review
Paleoneurology deals with the study of brain anatomy in fossil species, as inferred from the morphology of their endocranial features. When compared with other living and extinct hominids, Homo sapiens is characterized by larger parietal bones and, according to the paleoneurological evidence, also by larger parietal lobes. The dorsal elements of the posterior parietal cortex (superior parietal lobules, precuneus, and intraparietal sulcus) may be involved in these morphological changes. This parietal expansion was also associated with an increase in the corresponding vascular networks, and possibly with increased heat loads. Only H. sapiens has a specific early ontogenetic stage in which brain form achieves such globular appearance. In adult modern humans, the precuneus displays remarkable variation, being largely responsible for the longitudinal parietal size. The precuneus is also much more expanded in modern humans than in chimpanzees. Parietal expansion is not influenced by brain size in fossil hominids or living primates. Therefore, our larger parietal cortex must be interpreted as a derived feature. Spatial models suggest that the dorsal and anterior areas of the precuneus might be involved in these derived morphological variations. These areas are crucial for visuospatial integration, and are sensitive to both genetic and environmental influences. This article reviews almost 20 years of my collaborations on human parietal lobe evolution, integrating functional craniology, paleoneurology, and evolutionary neuroanatomy.
Topics: Biological Evolution; Humans; Neuroanatomy; Paleontology; Parietal Lobe
PubMed: 30099459
DOI: 10.1159/000488889 -
Neurobiology of Aging Jul 2020Contingency awareness is thought to rely on an intact medial temporal lobe and also appears to be a function of age, as older subjects tend to be less aware. The current...
Contingency awareness is thought to rely on an intact medial temporal lobe and also appears to be a function of age, as older subjects tend to be less aware. The current investigation used functional magnetic resonance imaging, transcranial direct current stimulation, and eyeblink classical conditioning to study brain processes related to contingency awareness as a function of age. Older adults were significantly less aware of the relationship between the tone-airpuff pairings than younger adults. Greater right parietal functional magnetic resonance imaging activation was associated with higher levels of contingency awareness for younger and older subjects. Cathodal transcranial direct current stimulation over the right parietal lobe led to lower levels of awareness in younger subjects without disrupting conditioned responses. Older adults exhibited hyperactivations in the parietal and medial temporal lobes, despite showing no conditioning deficits. These findings strongly support the idea that the parietal cortex serves as a substrate for contingency awareness and that age-related disruption of this region is sufficient to impair awareness, which may be a manifestation of some form of naturally occurring age-related neglect.
Topics: Adult; Aged; Aging; Awareness; Blinking; Conditioning, Classical; Female; Humans; Magnetic Resonance Imaging; Male; Middle Aged; Parietal Lobe; Temporal Lobe; Transcranial Direct Current Stimulation; Young Adult
PubMed: 32241582
DOI: 10.1016/j.neurobiolaging.2020.02.024 -
Alternative Therapies in Health and... Sep 2022Parietal lobe epilepsy (PLE) accounts for approximately 5% of all focal epilepsies worldwide,1 and few PLE patients have undergone epilepsy surgery in the past. With the...
CONTEXT
Parietal lobe epilepsy (PLE) accounts for approximately 5% of all focal epilepsies worldwide,1 and few PLE patients have undergone epilepsy surgery in the past. With the introduction of functional neuroimaging methods, such as interictal fluorodeoxyglucose-positron emission tomography (FDG-PET), stereotactic electroencephalograms (SEEGs), and high-resolution magnetic resonance imaging (MRI), more patients with intractable neocortical epilepsy have been considered for surgical treatment.
OBJECTIVE
The study intended to characterize the clinical features, aura, and presurgical evaluations of patients with PLE, by investigating their demographic and clinical characteristics, and to evaluate the prognostic value of the four diagnostic modalities-MRI, FDG-PET, scalp EEG, and SEEG-in terms of the localization of epileptogenic area.
DESIGN
The research team performed a retrospective analysis of outcomes for PLE patients who underwent resistive brain surgery.
SETTING
The study took place in the Neurosurgery Department of Epilepsy at the Second Hospital of Hebei Medical University in Shijiazhuang, China.
PARTICIPANTS
Participants were 9 PLE patients, 4 males and 5 females, who underwent epilepsy surgery at the hospital between 2017 and 2019.
OUTCOME MEASURES
The measures included demographic data, seizure data, electroencephalogram (EEG) recordings, magnetic resonance imaging (MRI) of the brain, positron emission tomography (PET), and stereotactic electroencephalogram (SEEG). The pathological findings were reviewed.
RESULTS
The five participants who had a PET all had positive results. Eight participants who had parietal lobe lesions had an MRI, and four had a stereotactic electroencephalogram (SEEG) that localized the epileptogenic zone. The interictal scalp EEG recordings for seven participants showed an abnormality, and six participants who had ictal surface EEG recordings showed parietal ictal EEG onset.
CONCLUSIONS
Surgical excision of epileptogenic foci is the main treatment for drug-resistant PLE. Parietal functional anatomy is the basis for understanding and diagnosing PLE. Aura, semiology, interictal EEG, and PET are an important foundation for evaluation of PLE patients, and the SEEG is the most valuable tool, allowing localization of the epileptogenic zone.
Topics: Electroencephalography; Epilepsies, Partial; Epilepsy; Female; Fluorodeoxyglucose F18; Humans; Magnetic Resonance Imaging; Male; Parietal Lobe; Retrospective Studies; Tomography, X-Ray Computed; Treatment Outcome
PubMed: 35751899
DOI: No ID Found -
Current Biology : CB Jul 2017The posterior parietal cortex, along with temporal and prefrontal cortices, is one of the three major associative regions in the cortex of the mammalian brain. It is...
The posterior parietal cortex, along with temporal and prefrontal cortices, is one of the three major associative regions in the cortex of the mammalian brain. It is situated between the visual cortex at the caudal pole of the brain and the somatosensory cortex just behind the central sulcus. Technically, any cortex covered by the parietal bone is referred to as 'parietal cortex', but the posterior sector, formally referred to as posterior parietal cortex, is indeed its own functional section of cortex, consisting of Brodmann's areas 5, 7, 39, and 40 in humans, areas 5 and 7 in macaques, and area 7 in rodents (Figure 1). Whereas the anterior parietal cortex in humans comprises primary somatosensory areas, the posterior parietal cortex has several higher-order functions. It is referred to as an 'associative' cortical region because it is neither strictly sensory nor motor, but combines inputs from a number of brain areas including somatosensory, auditory, visual, motor, cingulate and prefrontal cortices, and it integrates proprioceptive and vestibular signals from subcortical areas.
Topics: Animals; Humans; Mammals; Parietal Lobe
PubMed: 28743011
DOI: 10.1016/j.cub.2017.06.007 -
Trends in Cognitive Sciences Jan 2007Current views of the parietal cortex have difficulty accommodating the human inferior parietal lobe (IPL) within a simple dorsal versus ventral stream dichotomy. In... (Review)
Review
Current views of the parietal cortex have difficulty accommodating the human inferior parietal lobe (IPL) within a simple dorsal versus ventral stream dichotomy. In humans, lesions of the right IPL often lead to syndromes such as hemispatial neglect that are seemingly in accord with the proposal that this region has a crucial role in spatial processing. However, recent imaging and lesion studies have revealed that inferior parietal regions have non-spatial functions, such as in sustaining attention, detecting salient events embedded in a sequence of events and controlling attention over time. Here, we review these findings and show that spatial processes and the visual guidance of action are only part of the repertoire of parietal functions. Although sub-regions in the human superior parietal lobe and intraparietal sulcus contribute to vision-for-action and spatial functions, more inferior parietal regions have distinctly non-spatial attributes that are neither conventionally 'dorsal' nor conventionally 'ventral' in nature.
Topics: Attention; Brain Mapping; Functional Laterality; Parietal Lobe; Space Perception
PubMed: 17134935
DOI: 10.1016/j.tics.2006.10.011 -
Progress in Neurobiology Apr 2019A reduction in goal-directed behavior, or apathy, occurs in neurological and psychiatric disorders, though its neural substrates remain unclear. Deficits in circuits... (Review)
Review
A reduction in goal-directed behavior, or apathy, occurs in neurological and psychiatric disorders, though its neural substrates remain unclear. Deficits in circuits connecting the prefrontal cortex to subcortical regions are considered to underlie apathy. Although apathy is empirically associated with widespread changes in these regions, studies across disorders also link apathy with the lateral parietal cortex. Such variety in regional involvement is consistent with the established role of prefrontal and subcortical regions in models of goal-directed behavior, and with the suggestion of subtypes of apathy. However, these models do not provide a basis for the involvement of the lateral parietal cortex with apathy. Here, we review the association between lateral parietal cortex dysfunction and apathy across disorders and analyze the putative cognitive functions that may link this region with goal-directed behavior. We suggest that neural processes in the angular and supramarginal gyri of the inferior parietal lobule may provide an interface enabling the transformation of internal goals to external actions through intentional initiation of action interrelated with mechanisms of primary sensorimotor transformation. Consequently, we propose that impairment in this process of embedding intended action in a 'body schema' facilitating adequate recruitment of an effector system, is the likely mechanism underlying the association between the lateral parietal cortex and apathy. Considering the evidence, we propose a revised neurocognitive model of apathy where deficient internal initiation of behavior mediated by the inferior parietal lobule may be sufficient, though not necessary, to reduce goal-directed behavior, and may constitute a volitional subtype of apathy.
Topics: Animals; Apathy; Humans; Neural Pathways; Parietal Lobe
PubMed: 30590096
DOI: 10.1016/j.pneurobio.2018.12.003 -
NeuroImage. Clinical 2014Apraxia, a disorder of higher motor cognition, is a frequent and outcome-relevant sequel of left hemispheric stroke. Deficient pantomiming of object use constitutes a... (Review)
Review
Apraxia, a disorder of higher motor cognition, is a frequent and outcome-relevant sequel of left hemispheric stroke. Deficient pantomiming of object use constitutes a key symptom of apraxia and is assessed when testing for apraxia. To date the neural basis of pantomime remains controversial. We here review the literature and perform a meta-analysis of the relevant structural and functional imaging (fMRI/PET) studies. Based on a systematic literature search, 10 structural and 12 functional imaging studies were selected. Structural lesion studies associated pantomiming deficits with left frontal, parietal and temporal lesions. In contrast, functional imaging studies associate pantomimes with left parietal activations, with or without concurrent frontal or temporal activations. Functional imaging studies that selectively activated parietal cortex adopted the most stringent controls. In contrast to previous suggestions, current analyses show that both lesion and functional studies support the notion of a left-hemispheric fronto-(temporal)-parietal network underlying pantomiming object use. Furthermore, our review demonstrates that the left parietal cortex plays a key role in pantomime-related processes. More specifically, stringently controlled fMRI-studies suggest that in addition to storing motor schemas, left parietal cortex is also involved in activating these motor schemas in the context of pantomiming object use. In addition to inherent differences between structural and functional imaging studies and consistent with the dedifferentiation hypothesis, the age difference between young healthy subjects (typically included in functional imaging studies) and elderly neurological patients (typically included in structural lesion studies) may well contribute to the finding of a more distributed representation of pantomiming within the motor-dominant left hemisphere in the elderly.
Topics: Apraxias; Gestures; Humans; Magnetic Resonance Imaging; Neuroimaging; Parietal Lobe; Psychomotor Performance
PubMed: 24967158
DOI: 10.1016/j.nicl.2014.05.017 -
Epilepsia Dec 2011Ictal autonomic pupillary dilation is common; however, miosis is rare. We describe a case of focal seizures secondary to cortical dysplasia presenting with bilateral...
Ictal autonomic pupillary dilation is common; however, miosis is rare. We describe a case of focal seizures secondary to cortical dysplasia presenting with bilateral pupillary miosis, rendered seizure free by resective surgery. The seizure-onset zone was localized within the left middle parietal gyrus by intracranial electrographic recording. Seizure onset was coincident with focal left centroparietal fast spike activity on electroencephalography (EEG). A large region of the left frontocentral cortical dysplasia was demonstrated on magnetic resonance imaging (MRI). Complete resection of the area of cortical dysplasia and additional cortical regions of ictal activity, identified using intracranial EEG, rendered the patient seizure free.
Topics: Electroencephalography; Humans; Infant; Magnetic Resonance Imaging; Male; Malformations of Cortical Development; Parietal Lobe; Pupil Disorders; Seizures
PubMed: 22050551
DOI: 10.1111/j.1528-1167.2011.03310.x -
The Journal of Comparative Neurology Feb 2016Posterior parietal cortex (PPC) is an extensive region of the human brain that develops relatively late and is proportionally large compared with that of monkeys and... (Review)
Review
Posterior parietal cortex (PPC) is an extensive region of the human brain that develops relatively late and is proportionally large compared with that of monkeys and prosimian primates. Our ongoing comparative studies have led to several conclusions about the evolution of this posterior parietal region. In early placental mammals, PPC likely was a small multisensory region much like PPC of extant rodents and tree shrews. In early primates, PPC likely resembled that of prosimian galagos, in which caudal PPC (PPCc) is visual and rostral PPC (PPCr) has eight or more multisensory domains where electrical stimulation evokes different complex motor behaviors, including reaching, hand-to-mouth, looking, protecting the face or body, and grasping. These evoked behaviors depend on connections with functionally matched domains in premotor cortex (PMC) and motor cortex (M1). Domains in each region compete with each other, and a serial arrangement of domains allows different factors to influence motor outcomes successively. Similar arrangements of domains have been retained in New and Old World monkeys, and humans appear to have at least some of these domains. The great expansion and prolonged development of PPC in humans suggest the addition of functionally distinct territories. We propose that, across primates, PMC and M1 domains are second and third levels in a number of parallel, interacting networks for mediating and selecting one type of action over others.
Topics: Animals; Biological Evolution; Frontal Lobe; Humans; Neural Pathways; Parietal Lobe; Primates
PubMed: 26101180
DOI: 10.1002/cne.23838