A brain region {parietal lobe}| between frontal and occipital lobes and above temporal lobe is for movement, orientation, calculation, and recognition. It controls symbol use, spatial orientation, maps, space in general, body-side consciousness, numerical and logical relations, and sense associations. It understands speech parts, passive voice, and possessive case, in different subregions. It is for language, learning, and memory. It, mostly inferior parietal, participates in memory retrieval.
Attention affects parietal lobe [Bisley and Goldberg, 2003] [Colby and Goldberg, 1999] [Gottlieb et al., 1998].
damage
Parietal lobe damage disrupts memory, spatial cognition, and attention. Parietal lobe damage causes anomalous body experiences. Non-dominant, usually right, posterior parietal lobe damage can cause hemi-neglect and anosagnosia.
Parietal lobe regions {angular gyrus}| can be for reading and writing, detect number concepts such as cardinality and ordinality, and connect speech-behavior auditory information to visual information. Perhaps, left side is multisensory, and right is spatial [Ramachandran, 2004]. Angular gyrus expanded greatly from mammals to humans.
Parietal-lobe regions {primary auditory cortex} {area A1} {A1 area} can be adjacent to Wernicke's area and receive from medial geniculate nucleus, which receives from inferior colliculus, which receives from nucleus {lateral lemniscus nucleus}, superior olive, and cochlear nuclei. Lateral lemniscus nucleus receives from superior olive and cochlear nuclei. Superior olive receives from dorsal, posteroventral, and anteroventral cochlear nuclei and both ears. Cochlear nuclei receive from cochlea {spiral ganglion} auditory neurons.
processing
Y cells maintain activity after moving object crosses receptive field, using cortico-thalamic feedback.
Parietal regions {auditory cortex}| can be for hearing, sound, octaves, and tone patterns. It has frequency-sensing neuron field perpendicular to intensity-sensing neuron field.
processing
Specific brain places recognize sounds in word, speech, or sentence. Special places are for object names, word productions, writing, remembering words, and speaking spontaneously.
No matter the musical scale, people prefer octave tuned slightly higher than exact 2:1 frequency ratio.
damage
Primary hearing area destruction causes only high-tone loss. Bats can hear even with damaged primary auditory areas.
Auditory-cortex regions {corticofugal network} can learn sound patterns and send dopamine feedback to itself and higher regions.
Parietal-lobe back regions {dorsal parietal lobe} can be for well-being feeling.
Cells {grasping cell} can respond to grasping.
Inferior parietal lobe regions {inferior parietal lobe} (IPL) {caudal inferior parietal lobe} can have two main parts, LIP and 7a. Both LIP and area 7a receive input from thalamus medial pulvinar nucleus. Area LIP sends to superior colliculus and frontal eye fields to execute saccadic eye movements. Area 7a sends to polymodal cortex, limbic system, and prestriate cortex, to detect retinal locations and eye and head positions. Right or left Brodmann-area-7 damage causes hemi-neglect.
Speech area damage {left anterior parietal lobe} can harm syntax, sequential organized speech, and skilled movements but not affect phoneme, word, logic, or grammar production or understanding.
Left inferior parietal region {left inferior parietal} damage affects color-perception achromatopsia in fusiform gyrus, motion-perception akinetopsia in mediotemporal region, face perception in prosopagnosia, and feelings that there are imposters in Capgras syndrome [Nordby, 1990] [Perrett et al., 1992] [Scalaidhe et al., 1997] [Tranel and Damasio, 1985].
Association area {left inferoparietal} damage can cause various language problems.
Association area {left parieto-occipital} damage can cause various language problems.
Speech area damage {left posterior parietal lobe} can interfere with language acquisition and harm paradigmatically-organized speech production and understanding, but not affect syntax and organized speech.
Posterior area V4 and V4A regions {lunate sulcus} can analyze color and color constancy.
Human parietal-lobe regions {motor cortex}| {area M1} {Brodmann area 4} {precentral gyrus} {pre-central gyrus} {motor strip} can have two or three million motor neurons, control purpose, initiate voluntary movements, activate habits, cause automatic movements, and specify muscle positions needed at movement completion. Pre-central gyrus contains most corticospinal motor tract neurons.
output
Motor-cortex pyramidal neurons send to extrapyramidal-motor-system alpha and gamma motor neurons, to coordinate and initiate fast and precise movements. Motor neurons excite spinal cord neurons, which excite special muscle fibers in muscle spindles. Primary motor cortex connects to basal ganglia, thalamus, and other cerebral cortex [Bullock et al., 1977].
processing
Muscles move to reach specified muscle positions, as registered by muscle sensors. Motor cortex programs movements by controlling lower-level reflexes. Once started, motor program cannot stop, only change. Motor cortex neurons align by movement direction. Neurons signal particular limb-movement direction. Actual movement is sum of vectors. Primary motor cortex M1 activity shifts with intended-arm-movement coordinates [Amirikian and Georgopoulos, 2003] [Bullock, 2003] [Dean and Cruse, 2003] [Evarts, 1968] [Miall, 2003].
In isotonic movement, motor cortex and red nucleus neurons give intense burst, at frequency corresponding to movement velocity and duration corresponding to movement duration. In isotonic movement, Purkinje cells give bursts or pauses, to inhibit positive feedback to antagonists or allow positive feedback to agonists. In isometric movement, motor cortex and red nucleus neurons give intense burst, at frequency corresponding to force and duration corresponding to force rate. Motor cortex and red nucleus neurons can also have tonic output.
Sense information selects motor-program parameters to initiate program, to define movement endpoint through proprioception, and to guide subsequent adaptive process that mediates motor learning. Sense feedback shapes motor map, and vice versa.
Y cells maintain activity after moving object crosses receptive field, using cortico-thalamic feedback.
Muscle activity initiation always begins unconsciously in cerebrum. Conscious control can affect final motor nerve signals.
damage
Damage to motor cortex does not change learned mammal behavior patterns.
voluntary movement
Mammals have voluntary behavior and move bodies and appendages to specific space points {voluntary movement}.
voluntary movement
The two million motor neurons of human parietal-lobe motor-cortex area M1 initiate voluntary movements and specify muscle positions needed after movements. Muscles move to reach specific muscle positions, as registered by muscle sensors. Motor-cortex pyramidal neurons send to spinal-cord lateral corticospinal tract, which controls voluntary muscles by controlling reflexes.
vectors
Motor-cortex neurons contract specific muscle fibers, which move in relative direction from zero length change up to maximum length change. Fiber movements have magnitude and direction and so are vectors.
vector sums
Individual cortical cells have few connections to nearby neurons, so individual-neuron activation cannot provide enough signal strength to start or maintain movements {motor act}. Motor acts require multiple neuron pathways to achieve precise movement timing. Motor acts generate large precisely coordinated temporal-signal sequences to activate muscles. In contralateral superior colliculus, average neuron vector directs eye movement, or eye and head movement, to target object, using body-centered coordinates.
Neurons for attention to target control motor neurons. Brains control movements using few independent parameters. Motor acts require coordinated temporal motor-neuron activation and inhibition. To move limbs or body parts in specific directions, motor-cortex neurons contribute fiber movement. Total limb or body-part movement is sum of vectors and moves limb or body part from starting position to final position, using body-centered coordinates. Motor cortex accounts for starting position, finds vector sum, and moves to intended final position. Proprioceptive sense information defines starting and ending positions [Amirikian and Georgopoulos, 2003] [Bullock, 2003] [Dean and Cruse, 2003] [Miall, 2003].
input
Input from attention, planning, and drive neurons goes to all motor neurons.
movement-control parameters
Movement control uses several independent parameters. For isotonic movements with constant force, motor-cortex neurons fire for duration corresponding to movement duration, at rate corresponding to movement velocity. For isometric movements with no motion, motor-cortex neurons fire for duration corresponding to force duration, at rate corresponding to force.
In primates, parietal regions {area MT} {MT area} can analyze small object and large background motions and orientation. Adjacent neurons detect slightly different orientations in one direction and opposite orientations in perpendicular direction. MT also participates in recognition memory.
Parietal-lobe anterior-edge regions {post-central gyrus} can be tactile and kinesthetic sense areas. Its SI topographic map has Penfield homunculus.
Parietal lobe has posterior region {posterior parietal lobe} (PP) [Andersen, 1995] [Batista and Andersen, 2001] [Bisley and Goldberg, 2003] [Bruce et al., 1986] [Colby and Goldberg, 1999] [Glickstein, 2000] [Gross and Graziano, 1995] [Snyder et al., 2000].
input
Posterior parietal lobe receives from visual, auditory, and proprioceptive cortex.
output
Posterior parietal lobe sends to inferior-temporal-lobe superior temporal sulcus superior boundary, spinal cord, brainstem, prefrontal lobe, and frontal lobe.
functions
Posterior parietal lobe detects sense location, size, orientation, and motion direction. It represents attended object locations. It is for attention, shape transformations, category and spatial coordinate interactions, spatiotopic mapping, and spatial relations. In humans, it is about spatial cognition, in right hemisphere, and language understanding, in left hemisphere. It registers movement consequences, such as current eye position. Eye position multiplies receptive-field event [Zipser and Andersen, 1988]. It plans and initiates limb movements in primates. Map in cortical area 6 computes locations in nearby space, using body-based coordinates, and can guide orienting responses, like tectofugal pathway. Cortical area 7b has map of nearby space for motor control. Neurons respond to both receptive field changes and eye or head position [Andersen et al., 1985] [Andersen et al., 1997] [Pouget and Sejnowski, 1997] [Salinas and Abbott, 1995].
Parietal regions {suprasylvian visual area} can send to superior colliculi.
In primates, left-inferior parietal-lobe association regions {Wernicke's area} {Wernicke area} can be in left-superior temporal lobe below lateral fissure, next to primary auditory cortex, at vision, audition, and somaesthetic cortical junction. Wernicke's area has no connections to limbic system. Broca's area and Wernicke's area connect through arcuate fasciculus.
damage
Wernicke's area damage causes alexia, agnosia, tactile aphasia, and word deafness but does not affect writing or hearing. Disconnecting Wernicke's area from motor centers causes apraxia. Wernicke's aphasia causes bad semantics, paraphasia, imprecise words, circumlocutions, and neologisms, but speech is fluent, rapid, articulated, and grammatical.
4-Zoology-Organ-Nerve-Brain-Cerebrum
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Date Modified: 2022.0225