Posterior parietal cortex
Encyclopedia
The posterior parietal cortex (the portion of parietal neocortex posterior to the primary somatosensory cortex) plays an important role in producing planned movements. Before an effective movement can be initiated, the nervous system must know the original positions of the body parts that are to be moved, and the positions of any external objects with which the body is going to interact. The posterior parietal cortex receives input from the three sensory systems that play roles in the localization of the body and external objects in space: the visual system, the auditory system, and the somatosensory system. In turn, much of the output of the posterior parietal cortex goes to areas of frontal motor cortex: the dorsolateral prefrontal cortex
, various areas of the secondary motor cortex, and the frontal eye field. fMRI studies in monkeys and TMS
studies in humans indicate that the posterior parietal cortex comprises a mosaic of small areas, each specialized for guiding particular movements of eyes, head, arms or hands.
Damage to the posterior parietal cortex can produce a variety of sensorimotor deficits, including deficits in the perception and memory of spatial relationships, in accurate reaching and grasping, in the control of eye movement, and in attention. The two most striking consequences of PPC damage are apraxia
and hemispatial neglect
.
Some sources say that the PPC consists of Brodmann area 5
and Brodmann area 7
. Other sources say it is only area 7.
There is also evidence indicating that it plays a role in perception of pain.
Recent findings have suggested that feelings of "free will" at least partially originate in this area.
Dorsolateral prefrontal cortex
The dorsolateral prefrontal cortex , according to a more restricted definition, is roughly equivalent to Brodmann areas 9 and 46. According to a broader definition DL-PFC consists of the lateral portions of Brodmann areas 9 – 12, of areas 45, 46, and the superior part of area 47. These regions...
, various areas of the secondary motor cortex, and the frontal eye field. fMRI studies in monkeys and TMS
TMS
- Organizations :* The Minerals, Metals & Materials Society, a professional organization for materials scientists and engineers* Texas Memory Systems, a manufacturer of solid-state drives...
studies in humans indicate that the posterior parietal cortex comprises a mosaic of small areas, each specialized for guiding particular movements of eyes, head, arms or hands.
Damage to the posterior parietal cortex can produce a variety of sensorimotor deficits, including deficits in the perception and memory of spatial relationships, in accurate reaching and grasping, in the control of eye movement, and in attention. The two most striking consequences of PPC damage are apraxia
Apraxia
Apraxia is a disorder caused by damage to specific areas of the cerebrum. Apraxia is characterized by loss of the ability to execute or carry out learned purposeful movements, despite having the desire and the physical ability to perform the movements...
and hemispatial neglect
Hemispatial neglect
Hemispatial neglect, also called hemiagnosia, hemineglect, unilateral neglect, spatial neglect, unilateral visual inattention, hemi-inattention or neglect syndrome is a neuropsychological condition in which, after damage to one hemisphere of the brain, a deficit in attention to and awareness of...
.
Some sources say that the PPC consists of Brodmann area 5
Brodmann area 5
Brodmann area 5 is one of Brodmann's cytologically defined regions of the brain. It is involved in somatosensory processing and association.-Human:Brodmann area 5 is part of the parietal cortex in the human brain...
and Brodmann area 7
Brodmann area 7
Brodmann area 7 is one of Brodmann's cytologically defined regions of the brain. It is involved in locating objects in space. It serves as a point of convergence between vision and proprioception to determine where objects are in relation to parts of the body....
. Other sources say it is only area 7.
There is also evidence indicating that it plays a role in perception of pain.
Recent findings have suggested that feelings of "free will" at least partially originate in this area.