N2T15: Functional cortical centers

what are the motor areas?

primary somatomotor cortex (br.4)

premotor + supplementary motor cortex (br.6)

frontal eye field (br.8)

brocca's area, motor-speech center (br.44/45)

where is the primary somatomotor cortex located?

precentral gyrus

what do the internal pyramidal layer of the precentral gyrus contain?

giant pyramidal cells of Betz

what do the axons of the giant pyramidal cells of betz in the precentral gyrus form?

the corticonuclear and corticospinal tracts

where do the axons of the primary efferents of the br.4 go from and to?

5th layer to subcortical areas

where do the axons of the secondary efferents of the br.4 go from and to?

3rd layer to other cortical areas

where do the axons of the primary afferents of the br. 4 go from and to?

from subcortical areas to 4th layer

where do the axons of the secondary afferent of the br. 4 go from and to?

association and commiccural fibers from other cortical areas to 2nd layer

what do stimulation of the primary somatomotor cortex result in?

contralateral movement of voluntary muscles, especially distal muscles of the limb

what can lesion of the precentral gyrus lead to?

contralateral upper motor neuron lesion → hemiparesis or hemiphlegia on the contralat. side

where is the premotor + supplementary motor cortex (br.6) located?

anterior to precentral gyrus, consist mostly of the superior (and middle) frontal gyri

function of br.6?

planning and programming of movements executed in the primary motor cortex

from where does the br.6 receive connections?

sensory cortex, thalamus and basal ganglia

which system is br.6 considered a part of?

extrapyramidal system

where does br.6 project fibers to?

primary motor area, basal ganglia, cerebellum, red nucleus and reticular formation

what can lesion in the dominant hemisphere in the premotor cortex cause?

sympathetic apraxia

what can lesions in the premotor area lead to ?

the inability to execute complex movements, ideomotor apraxia

where is the frontal eye field (br. 8) located?

middle (and superior) frontal gyri

function of frontal eye field

controls voluntary + reflex eye movements

which structures do the frontal eye field receive afferents from?

primary and secondary visual centers and thalamus

where does the frontal eye field project fibers to?

via corticotectobulbar tract to the contralateral gaze center of the pons.

to tectum of the midbrain

pretectal areas

through reticular formation of CN III, IV and VI

cerebellum

Where is Brocca's area located?

located in the posterior part of the inferior frontal gyrus

middle (triangular) part br. 45

posterior (opercular) part. br. 44

how is brocca's area connected to wernicke's area?

by arculate fasciculus

Brocca's area function?

speech production

what can lesion of the brocca's area cause?

total or partial paralysis of speech → motor aphasisa

what are the sensory areas?

wernicke's area (br. 22, 39 and 40)

primary somatosensory areas (br. 3,1,2)

secondary somatosensory cortex

sensory assoication areas (br. 5 and 7)

primary visual cortex (br.17)

secondary and tertiary visual centers (br.18,19)

visual association cortex (br.39)

primary auditory cortex (br.41,42)

auditory association cortex (br.22)

gustatory cortex (br.43)

olfactory area (br.28)

vestibular cortex (br.2)

where is the restricted wernicke's located?

posterior part of the superior temporal gyrus

where is the extended wernicke's located

supramarginal and angular gyrus

supramarginal gyrus (extended wernicke's) function?

connects somatosensory, auditory and visual inputs together

Wernicke's area function?

language comprehension

Lesion to Wernicke's area

total or partial sensory aphasia

where is the primary somatosensory cortex located?

postcentral gyrus of the parietal lobe

primary somatosensory cortex function?

registers and processes sensory information from receptors in the body

from where does the primary somatosensory cortex receive afferents?

VPM/VPL of thalamus and from association nuclei

where does the primary somatosensory cortex project fibers to?

primary motor area

secondary SS area

association areas

lower replay stations: medulla oblongata, thalamus and the spinal cord

primary somatosensory cortex, contralat. or ipsilat. info?

mostly contralateral, but from the oral region it goes to the same side, and from pharynx, larynx and perineum it goes to both sides

in which layer do the afferent fibers for the sensory cortex mostly terminate?

4th layer

secondary SS cortex location?

ventral to the primary SS area along the superior bank of the lateral sulcus

sensory association areas (br.5 and 7)location?

located in the superior and inferior parietal lobules

from where does the sensory assoication areas receive input?

from areas 3, 1 and 2

br.7 also from area 19

sensory association areas function?

orientation, memory of places, sensory/visual/auditory recognition

destruction of sensory association areas?

contralateral losses of tactile discriminarion

stereognosis: ability to perceive and recognize forms

statognosis: ability to recognize the position of body parts in space

on one side: neglect syndrome

lesion of supramarginal gyrus in dominant hemisphere?

ideomotor apraxia

sensory apraxia

facial apraxia

conduction aphasia

ideomotor apraxia?

the inability to carry out a simple motor activity in response to a verbal command

sensory apraxia?

inability to formulate the ideational plan for executing the several components of a complex multistep task

facial apraxia?

Inability to perform facial

oral movements on command

conduction aphasia?

Poor repitition of spoken language

primary visual cortex (br.17) location?

around the calcarine sulcus (cuneus and lingual gyri)

from where does the primary visual cortex receive input?

lateral geniculate body, via optic radiation

where does the primary visual cortex send radiations?

to secondary and tertiary visual centers

destruction of primary visual cortex symptoms?

visual field deficits

secondary and tertiary visual centers (br.18 and 19) location?

surrounds the primary visual center

secondary visual cortex function?

Concerned with perception of depth.Analysis of the visual fields and objects

tertiary visual cortex function?

Concerned with color perception and puts everything together

from where does the secondary and the tertiary visual center receive input?

primary visual cortex

where does the secondary and tertiary visual centers project efferents to?

pretectal area, premotor cortex and frontal eye field

lesion of secondary and tertiary visual centers?

visual hallucinations

visual association cortex (br. 39) location?

angular gyrus(part of extended wernickes)

from where does the visual association cortex receive input?

br. 18 and 19

destruction of the underlying visual radiation?

contralateral homonymous hemianopia or lower quadrantanopia

destruction of visual association cortex in the dominant hemisphere?

Gestmann syndrome

primary auditory cortex (br.41,42) location?

transverse temporal gyri of heschl, located in the superior temporal gyrus

from where does primary auditory cortex receive input?

medial geniculate body, via acoustic radiation

where does the primary auditory cortex project fibers to?

auditory association cortex

primary auditory cortex function?

ant. part: reception of sounds w. low freq.

post. part: reception of sounds w. high freq.

unilateral destruction of primary auditory cortex?

partial deafness

auditory association cortex (br.22) location?

located in the posterior part of the superior temporal gyrus

from where does auditory association cortex receive input?

from the primary auditory cortex and MGB

where does auditory association cortex project fibers to?

to speech areas and association areas

lesion in auditory association cortex (dominant hemisphere)?

sensory aphasia

lesion in auditory association cortex (non-dominant hemisphere)?

sensory disprosody

auditory association areas function?

distinguishing, analyzing and perceiving complex sounds, tones and voices

gustatory cortex (br.43) location?

located in the parietal operculum and the parainsular cortex

from where does the gustatory cortex receive input?

nuclei of solitary tract via VPM nucleus of thalamus

gustatory cortex function?

perception of taste

olfactory area (br.28) location?

located in the parahippocampal gyrus

afferents to olfactory area?

from olfactory bulb and lateral olfactory stria

which cortex has reciprocal connection with the olfactory area?

orbitofrontal association cortex

olfactory area function?

perception and distinguishing olfactory stimuli

vestibular cortex (br.2) location?

small region of the postcentral gyrus, next to lateral sulcus

afferents to vestibular cortex?

from VPM nucleus of thalamus

vestibular cortex function?

perception of head position and movement in respect to the rest of the body

what are the multifunctional areas?

the insular areas (br.13-16)

insular areas (br.13-16) location?

insular lobe

insular areas afferents?

from VPM and VPL and intralaminar nuclei of the thalamus

insular areas efferents?

frontal, parietal and temporal lobes

amygdaloid body

entorhinal and paraamygdalar areas of olfactory cortex

insular areas function?

ventral part: VS, perception of gustatory stimuli, integration w. olfactory perception and regulation of the immune system

middle part: Motor, influences respiratory movements and activity of breathing muscles

dorsal part: Vestibular, perception of head position and movements

what are the association areas?

prefrontal cortex (br.9-12, 46 and 47)

parietal association areas (br. 5 ,7, 39 and 40)

temporal association areas (br. 20-22, 37-38)

occipital association areas (br.18,19)

prefrontal cortex function?

cortical center of emotions, behavior, planning, ego and personality, creative thinking and complex memory circuits

Phineas Gage syndrome?

lesion of prefrontal cortex.inappropriate social behavior, difficulty in adaptation, loss of iniative and sucking, groping and grasping reflexes

parietal association areas?

br. 5,7, 39 and 40

parietal association areas location?

located in the superior and inferior parietal lobules

parietal association areas function?

complex perception of stimuli and integration of sensory inputs. participate in the creation of a 3D-map of surrounding, and its activity is important for spatial orientation and fine motor timing

temporal association areas?

br. 20,21,22,37 and 38

temporal association areas location?

in the temporal lobe and occipitotemporal gyrus

temporal association areas function?

distinguishing familiar and unfamiliar faces, objects and animals

occipital association areas?

br. 18 and 19

function of occipital association area?

detailed analysis and synthesis of visual stimuli

visual agnosia

primary visual center is intact, but there are problems related to the secondary, tertiary and association centers

tactile agnoisa?

patient can't feel and recognize objects by touch