Neuro Lecture 4

• Fractionated hand movement
• Symbolic thought
• Personality
• Conscience
• Self-awareness

Individual sensory modalities that are considered to be the functional unit of the cortex.

• Achicortex
• Paleocortex
• Neocortex

• Oldest
• 2 cell layers
• Hippocampus

• Old
• 3 cell layers
• olfactory cortex

• New
• 6 cell layers
• Most of frontal, parietal, temporal, and occipital cortex

Input and Output

• Specialized areas
• Association areas

Form the control centers for specific functional systems (primary projection regions)

Responsible for integrating input from specialized areas

• Interhemispheric
• Intrahemispheric
• Projection

• Commissural Fibers
• Connect functionally related areas from two hemispheres
• Largest fiber bundle in the nervous system
• Includes: Corpus Callosum, Anterior and Posterior Commissures

• Association Fibers
• Project anterior-posteriorly connecting functionally relates areas within the same hemisphere
• -External capsule
• -Extreme capsule

• Corticopetal (fibers from outside into the cerebral cortex)
• Corticofugal (cortex to downstream targets)
• Internal Capsule

• Verbal
• Sequential
• Analytical
• Detail
• Rational

• Nonverbal
• Spatial
• Perceptive
• Holistic
• Emotional

Disorder of language

Difficulty performing learned skilled movements

Inability to know (recognize) familiar objects/sounds

• Stroke
• Seizure disorder
• Alzheimer's Disease
• Psychiatric disorders (e.g. Schizophrenia)

Impairment in the execution of speech and often occurs without a disorder of language (lesion of craial nerves or other motor areas)

Language development in left hemisphere

Nonfluent, motor, productive, expressive or anterior aphasia

Pattern for sounds and for the structure of language are not passed on to the motor cortex

• Comprehension preserved
• Speech is not fluent
• Language production ranges from nearly complete muteness to slowed, deliberate speech
• Use only key words
• Generally aware of errors
• Reading and writing (like speech) is abnormal
• Almost always with Right hemiparesis and homonymous hemianopsia (due to anatomy)

Fluent, sensory, receptive, or posterior aphasia

Words reacing the auditory cortex fail to activate Wernicke's area and are not comprehended.

• Deficit in comprehension
• Speech is fluent
• Language is normal in rate, rhythm, and melody
• May use wrong words
• Add additional syllables to words or words with phrases
• Neologisms (made up words)
• Press of speech (excessive language)
• "Empty speech"
• Generally unaware of impairment
• Inabillity to repeat words/phrases
• Severe reading and writing disabilities

Arcuate Fasciculus

Combination of both productive and receptive aphasia with a complete loss of the ability to comprehend spoken or written language, as well as express language verbally or orthographically

• Damage to arcuate fasciculus
• Fluent with many paraphasic errors
• Comprehension is good
• Impaired ability to repeat
• Naming impaired
• Reading aloud impaired but silent reading is good
• Poor spelling
• Other aphasias

Inability to perform previously learned movements in the absence of weakness, sensory loss, or impairment of language comprehension

• Ideomotor apraxia
• Ideational apraxia
• Kintec (Motor) apraxia

• Inability to perform complex motor tasks despite awareness of the intended task
• Can perform many complex tasks automatically but cannot carryout the same tasks on command

Inability to carry out sequences of acts, althought individual movements can be made correctly

Due to a lesion of the supramarginal gyrus in the dominant hemisphere

Due to lesion of the parietal lobe in the dominant hemisphere or the corpus callosum

Inability to perform fine learned movements in the absence of weakness or sensory loss.

Due to bilateral lesion (disease) of the frontal lobes

Process of knowing or comprehension involving comparison of current sensory data with past experience

Failure to recognize stimuli when appropriate sensory systems function properly

• Visual agnosia
• Tactile agnosia
• Auditory agnosia

Failure to recognize objects visually in the absence of impairment of visual acuity or cognition

Due to bilateral lesion of temporal aspect of visual unimodal association areas

Agnosia of familiar faces

Inability to recognize objects by touch when tactile and proprioceptive sensations remain intact

Due to lesion of supramarginal gyrus

Failure to recognize specific sounds, including speech, music, and familiar noises with intact hearing

Due tobilateral lesions of osterior part of the superior temporal gyrus

disruption of abillity to read (acquired and congenital, respectively)

Inability to write

• Usually caused by a lesion of the parietal lobe in the non-dominant (spatial) hemisphere (right)
• Can be associated with hemianopsia

Produced by the failure of surround inhibition leading to synchronized discharge of a group of cortical columns

Produced by the synchronized discharge of a "small" number of cortical columns.

Produceed by the synchronized discharge of both hemispheres

Some patients exhibit enlarged lateral ventricles, enlarged third ventricles and widening of sulci