NDT Exam 2 LO 31-38 ( 4th slideshow)

What are the gyri?

• Ridges

what are the sulci?

grooves inbetween

what purpose do the gyri and sulcus serve

increase surface area

what is the function of the longitudinal fissure

separate the cerebral hemispheres

what is the purpose of the corpus callosum

the tracts of white matter that connect cerebral hemispheres

What are the four main fissures/sulci

1. longitudinal: separates cerebral hemispheres

2. central sulcus: separates frontal + parietal lobes

3. lateral sulcus: separates the frontal/parietal lobes from the temporal lobe

4. parieto-occipital sulcus: between parietal + occipital lobes

what three TBI are there

• coup

• contrecoup

• coup-contrecoup

what happens during a coup

injury on the brain directly below site of impact

what happens during a contrecoup

• force of impact causes the brain to strike the opposite side of the skull

  • affects opposite side of brain

what happens during a coup-contrecoup

• both sides are impacted

  • often associated with permanent brain damage

what is neuron migration

forms all brain structures including layers of cerebral cortex

what is the proces for neuron migration

* neuronal/glial cells = radial glia

• cells divide

  • one remains as radial glia

  • other differentiates into neuroblasts

• radial glia send processes from the ventricular zone toward the surface

• neurons use process as guide to migrate + form layer known as cortical plate

• neurons that formed the original cortical plate differentiate to become sub plate

• new layer of neurons arrives to form a new cortical plate

  • differentiate to become critical layer VI

Process repeats until all layers of the cortex have differentiated

• then subplate neurons disappear

What are the lobes of the cerebral cortex

• Frontal

• Parietal

• Occipital

• Temporal

• Insula

Where is the frontal lobe located and what are the functions

• Located: under the frontal bone

• Function: voluntary motor control (premotor cortex)

• Executive Functions:

  • planning

  • mood

  • motivation

  • personality

  • socially appropriate behavior

  • emotional controls

• (prefrontal cortex)

What can damage to the frontal lobe cause (clinical applications)

• Motor apraxia

  • damage to pre motor cortex

  • inability to perform learned movements on command

what are the functions of the parietal lobe

• somatosensory processing (general senses)

• gustatory (taste) center

what could happen if the parietal lobe was damages (clinical applications)

• Gerstmann syndrome: loss of four specific functions

  • inability to distinguish R/L

  • can’t identify fingers

  • writing (dysgraphia)

  • math (acalculia)

• Astereognosis:

  • inability to identify objects by touch (without other sensory input)

• Sensory apraxia

  • loss of the ability to make proper use of an object

    • lack of perception of its use/purpose

• Neglect syndrome

  • damage to an entire side

  • inability to perceive + process stimuli from one side of the body

  • contralateral

What is the function of the occipital lobe

visual processing

what happens if there is damage to the occipital lobe (clinical applications)

• Contralateral hemianopsia: loss of visual field

  • damage to the right occipital lobe = loss of left visual field

  • damage to the left occipital lobe = loss of right visual field

* affects both eyes

what are the functions of the temporal lobe

• auditory processing center

• olfactory processing center

• memory function

what happens if there is damage to the temporal lobe (clinical application)

• Prosopagnosia:

  • inability to recognize the faces of familiar people

What is the location and function of the insula

• hidden by other regions

• deep to the lateral/sylvian fissure

• Function: taste, ANS, etc.

• not well understood

What are the functions of the cerebrum

• higher cognitive functions

  • executive functions/learning

• consciousness

• memory

• perception of sensation

• control of skeletal muscles

  • premotor cortex + basal nuclei

what are the 3 types of cerebral tracts made of white matter

1. Projection: unite the cerebral cortex with the lower parts of the brain + spinal cord (vertical)

2. Commissural: connect two hemispheres of the cerebrum (corpus callosum)

3. Association: connect cortical areas (gyri) within the same hemispheres

what is the lateralization of cerebral hemispheres

Brain hemispheres specialize in different functions

what does the left hemisphere specialize in

• Language

• Logic

• Analytical tasks

what does the right hemisphere specialize in

• Spatial awareness

• Emotional interpretation

• Creativity

what is the location and function of the precentral gyri

• Primary motor cortex

• Contains upper motor neurons

• Controls voluntary movement

• Motor homunculus shows body mapping

• fine motor control = small motor units

what is the location and function of the postcentral gyri

• Primary somatosensory cortex

• Receives touch, pain, temperature, proprioception

• Sensory homunculus:

  • Larger cortical area = higher sensitivity

what is the function of wernicke’s area in language

• permits recognition of spoken and written language and creates plan of speech

• formulates phases according to learned rules of grammar

• transmits plan of speech to broca area

what is the function of broca’s area in language

• generates motor program for the muscles of the larynx, tongue, cheeks, and lips

• transmits program to the primary motor cortex for commands to the lower motor neurons that supply relevant muscles

what is aphasia

inability to understand or express speech

what are the three types of aphasia

• Nonfluent (Broca) aphasia

• fluent (Wernicke) aphasia

• anomic aphasia

what happens in nonfluent aphasia

• can’t understand speech

• struggle to get words out/use words

what happens in fluent aphasia

• speak in normal-sounding grammatically correct sentences

• words are not correct/have no meaning

• cannot comprehend speech but can comprehend written words

what happens in anomic aphasia

• can comprehend

• can’t find right words to express what they want to say

• common outcome following stroke