The behavioral and neuronal bases of executive function have been well studied in neuropsychological patients (12 ⇓ — 14) and with functional neuroimaging (9, 12, 15 ⇓ — 17), which confirm that executive function is supported by a network of brain regions, primarily involving the frontal lobes and
the posterior parietal cortex (9, 12, 15 ⇓ — 17).
The results of the trial were published in a paper titled, «Hand Shape Representations in the Human
Posterior Parietal Cortex.»
Host: Dr. Miriam Spering Speaker: Dr. Richard Andersen, Caltech Title: Decoding imagined movements from
the posterior parietal cortex of tetraplegic humans
The paper is titled «Partially Mixed Selectivity in Human
Posterior Parietal Association Cortex.»
The first montage targeted right prefrontal cortex and
posterior parietal sites (anode PFC - cathode PPC).
Shomstein, S. Cognitive functions of
the posterior parietal cortex: top - down and bottom - up attentional control.
We will record from different brain areas, including the prefrontal cortex,
posterior parietal cortex, amygdala and hippocampus, as the animals perform the task.
The spatial mapping might also arise from a physical map of numbers in the brain, which has been found in humans in the right
posterior parietal cortex but has not yet been seen in animals.
Neurons in the human
posterior parietal cortex encode high - level aspects of imagined movements.
In a normal brain, imagining tennis activates the supplementary motor area of the cortex, and picturing one's home prompts activity in regions involved in spatial perception, such as
the posterior parietal cortex.
For their experiments, the scientists focused on neurons in
the posterior parietal cortex — the part of the brain where visual sensory input and motor action converge.
It was clear that certain neurons in
the posterior parietal cortex are responsible for the planning of arm movements.
The rhesus monkeys were trained to move their hands to a light cue on a touch screen (for example from the center of the screen to the left), while at the same time the activity of neurons in
their posterior parietal cortex was recorded.
Eight different regions displayed extra activity — in other words benefited from increased blood flow — when dealing with imagining the future, including Brodmann's area, the medial
posterior parietal cortex and the posterior cerebellum, among others.
The posterior parietal cortex (PPC) helps the brain separate self from the environment.
The role of
posterior parietal cortex in beat - based timing perception: a continuous theta burst stimulation study.
But when
the posterior parietal cortex was suppressed, all of the adults had trouble keeping rhythm.
Liu and his team implanted a pair of small electrode arrays in two parts of
the posterior parietal cortex, one that controls reach and another that controls grasp.
Levy's research found a connection between risk preferences and the quantity of neurons in a different part of the brain (called
the posterior parietal cortex), but not the amygdala or medial prefrontal cortex.
«Our results showed that the changes of spectral power in neural sources localized to
the posterior parietal cortex and sensorimotor cortex are associated with the level of motor task demands,» they wrote.
The researchers found several areas of the brain are involved, including the right and left occipital lobes,
the posterior parietal lobe, the sensorimotor cortex and the anterior cingulate.
But this team went further upstream in the brain's signaling chain and used signals from a patient's
posterior parietal cortex (PPC).
Not exact matches
Increase in donations was linked to bilateral lesions in the dorsomedial
parietal cortex, while decrease in donations was observed in the veterans who had suffered damage in
posterior parts of the right hemisphere, including superior temporal sulcus and middle temporal gyrus.
Together with the
posterior attentional system, located largely in the
parietal lobes, it tracks and regulates behavior.
In this week's Nature, they show that a large part of the
posterior cortex at the occipito -
parietal junction and two parts of the prefrontal cortex came into play.
Patients whose
posterior superior
parietal lobes have been damaged often lose the ability to navigate through the world, because they have difficulty determining where their physical selves end and where the external world begins.
Newberg's scans showed that neural activity decreases in a region at the top and rear of the brain called the
posterior superior
parietal lobe.
Strong associations between full - scale IQ and individual normalized path length were found in medial prefrontal gyrus, precuneus /
posterior cingulate gyrus, and bilateral inferior
parietal regions (Fig. 3).
Most prominent effects between IQ and the level of global connectivity efficiency (as expressed by a shorter node specific normalized path length) were found in the medial prefrontal cortex (yellow box), bilateral inferior
parietal cortex (red box depicts effect in right hemisphere), and precuneus /
posterior cingulate regions (orange box) of the functional brain network.
The most prominent effects between full - scale IQ and normalized path length were found in medial prefrontal gyrus (Brodmann area 9/10, r = − 0.75, p = 0.001, df = 18, yellow box), precuneus /
posterior cingulate gyrus (BA 7/31, r = − 0.55, p = 0.014, df = 18, orange box), and bilateral inferior
parietal regions (BA 39/40, right inferior
parietal: r = − 0.72, p = 0.001, df = 18 depicted in red box; left inferior
parietal: r = − 0.68, p = 0.001, df = 18).
Activations were mainly left - sided and involved the left supplementary motor area and supramarginal and
posterior superior temporal gyri, the last two overlapping with the temporal
parietal junction that has been associated with out - of - body experiences.
The combination of the data sets into a three - dimensional surgical planning model allowed the surgeons to map multiple trajectories and choose the best one: through the
posterior medial
parietal lobe, superior to the optic radiations and
posterior to the somatosensory cortex, to the lesion.
Among the brain regions implicated in this network, several, including the
posterior cingulate cortex and inferior
parietal lobes, have also shown decreased metabolism early in the course of Alzheimer's disease (AD).
At baseline, older adults showed significantly decreased hippocampal connectivity with medial prefrontal and parahippocampal cortex, and increased hippocampal connectivity with
posterior cingulate, precuneus, and
parietal cortex, relative to young adults (n = 16, age range: 18 - 34 years).
These modules include the visual (yellow), sensory / motor (orange) and basal ganglia (red) cortices as well as the default mode network (precuneus /
posterior cingulate, inferior
parietal lobes, and medial frontal gyrus; maroon).
Using ICA, Damoiseaux et al. [20] described two RSN components that together included the superior and middle frontal gyrus,
posterior cingulate, middle temporal gyrus and superior
parietal cortices.
Cluster a (a) shows the default mode network, consisting of frontal regions, including superior frontal gyrus (BA 8/9) and medial frontal gyrus (BA 10/11) and precuneus /
posterior cingulate cortex (BA 23/31) and bilateral regions overlapping middle / superior temporal tyrus (BA 21/39) and inferior / superior
parietal cortex (BA 39/40).
However, certain areas such as the
posterior cingulate cortex and precuneus, some lateral
parietal areas, and associated paramedian thalamic nuclei, may constitute strategic crossroads for coordinating the interactions among different sensory maps and frames of reference concerning the body and the environment.
What was startling was that the MRI scans showed that mindfulness groups increased gray matter concentration within the left hippocampus, the
posterior cingulate cortex, the temporo -
parietal junction, and the cerebellum.
Higher expenditure of energy was associated with larger gray matter volumes in the
parietal, temporal and frontal lobes, which included the basal ganglia,
posterior cingulate and hippocampus.
Neuroscientist Sara Lazar, Ph.D., along with her colleagues, found that as little as eight weeks of daily practice can enlarge four different areas of the brain: the
posterior cingulate, left hippocampus, temporo
parietal junction, and the brain stem.