Functional neuroanatomy of language and its disorders A

Functional neuroanatomy of language and its disorders A Concise Overview By: Shimon Neuman

Terminology Superior Anterior Inferior Posterior

Terminology Parietal Lobe Frontal Lobe Occipital Lobe Temporal Lobe

Broca’s Area Wernicke’s Area

Planning the message Preparing the phonology Motor Planning Accessing the semantic properties of the words Grammar Articulation Accessing the phonologic properties of the words Accessing the sensory and motor properties of the words (Rohrer et al. , 2007)

Planning the message • Occurs in the prefrontal cortex. What can go wrong? • Dynamic Aphasia: inability to plan a message. In its pure form no other area of language production or comprehension is impaired. (Robinson, Blair, & Cipolotti, 1998)

Accessing the concepts • Occurs in the middle and inferior temporal gyri. What can go wrong? • Semantic Dementia: inability to access semantic data. (Semantic memory loss) • Transcortical sensory aphasia: compromised naming and comprehension skills. (Hickok, 2009; Rohrer et al. , 2007)

Accessing the phonologic properties of the words • Occurs posterior superior temporal sulcus and middle temporal gyrus. What can go wrong? • Transcortical sensory aphasia: Naming and auditory comprehension is compromised (Gow, 2012)

Accessing the sensory and motor properties of the words • Occurs in the inferior parietal region including the supramarginal gyrus. What can go wrong? • Wernicke's aphasia: Difficulty understanding and producing meaningful language (Gow, 2012; Rohrer et el, . 2007)

Transferring to the Frontal Lobe The arcuate fasciculus (red What can go wrong? and green in MRI image top and schematic Anomic Aphasia: Difficulty bottom) connects the temporal retrieving words. In its pure lobe to the frontal lobe. form no other aspect of language is compromised. (Rilling & Glasser, 2008) (Fridriksson, Kjartansson, Morgan, Hjaltason, & Magnusdottir, 2010)

Accessing the correct grammar • Occurs in the inferior posterior frontal gyrus (Broca’s area. ) What can go wrong? • Non fluent aphasia: Inability to produce fluent speech. (Broca, 1861)

Preparing and organizing the phonology • Occurs in the inferior posterior frontal gyrus (Broca’s area. ) What can go wrong? • Non fluent aphasia: Inability to produce fluent speech. (Broca, 1861)

Motor planning • Occurs in: • Broca’s area • Left insula • Subcortical Regions What can go wrong? • Non fluent aphasia: Inability to produce fluent speech. (Ogar, Slama, Dronkers, Amici, & Gorno-Tempini, 2005; Beal, 2005)

Executing the articulation • Involves the motor neuron tract. What can go wrong? • Ataxic dysarthria • Hyperkinetic dysarthria • Hypokinetic dysarthria • Spastic dysarthria • Flaccid dysarthria (Mc. Caffrey, 1999)

Ataxic dysarthria Effects the cerebellar Symptoms: Responsible for: • Fine Movement Coordination • Muscle Tone Articulation: • Prosody: Irregular articulatory • breakdowns. Excess and equal stress • Irregular speech Excess loudness alternating motion rate variations (AMR). • Distorted vowels (Mc. Caffrey, 1999; "Mixed Dysarthria, " n. d. )

Hyperkinetic dysarthria Effects the Extrapyramidal tract, specifically the basal ganglia Responsible for: • involuntary reflexes and movement Symptoms: Respiration: • Phonation: Audible inspiration • • Sudden forced inspiration Harsh voice Articulation: • • Voice tremor Distorted vowels Resonance: • • Shortness of breath Irregular articulatory • Prosody: Intermittent hypernasality breakdowns • Inappropriate silences • Slow/irregular AMRs • Excessive loudness variations • variable patterns of stress and rate (Mc. Caffrey, 1999; "Mixed Dysarthria, " n. d. )

Hypokinetic dysarthria Effects the Substantia nigra Symptoms: Responsible for: • Control of voluntary Movement Respiration: • Phonation: Decreased vital capacity • Articulation: Shallow breathing Harsh & breathy voice Uncoordinated • Resonance: Periods of dysphonia Distorted & incorrect chest/diaphragm production of phonemes • Prosody: Minimal hypernasality • • Incorrect consonant Monopitch • blending Monoloudness • • Palilalia Reduced stress • • Replacing stops with Inappropriate silences • fricatives Variable rate (Mc. Caffrey, 1999; "Mixed Dysarthria, " n. d. )

Spastic dysarthria Effects the pyramidal tract Symptoms: Responsible for: • Transmission of voluntary Movement Phonation: • Articulation: Breathy voice • • Resonance: Strained-strangled vocal Imprecise consonants quality • • Prosody: Slow rate Hypernasality • • Low pitch • • Short phrases Reduced, excess, & • Harshness Distorted vowels • equal stress Pitch breaks • Monoloudness • Monopitch (Mc. Caffrey, 1999; "Mixed Dysarthria, " n. d. )

Flaccid dysarthria Effects motor units of cranial or spinal nerves Symptoms: Phonation: • Articulation: Breathy & harsh voice • • Resonance: Audible inspiration Imprecise consonants • • Short phrases Hypernasality Prosody: • Monoloudness • Monopitch Responsible for: • Transmission of voluntary Movement (Mc. Caffrey, 1999; "Mixed Dysarthria, " n. d. )

References Beal, J. A. (2005, November 30). Frontal (Coronal) section of the brain [Photograph]. Retrieved from http: //upload. wikimedia. org/wikipedia/commons/5/59/Human_brain_fron tal_%28 coronal%29_section_description_2. JPG Broca, P. P. (1861). Loss of speech, chronic softening and partial destruction of the anterior left lobe of the brain. Bulletin de la Société Anthropologique, 2, 235 -238. Fridriksson, J. , Kjartansson, O. , Morgan, P. S. , Hjaltason, H. , & Magnusdottir, S. (2010). Impaired speech repetition and left parietal lobe damage. The Journal of Neuroscience, 30(33), 11057 -11061. Gow, D. W. , Jr. (2012). The cortical organization of lexical knowledge: A dual lexicon model of spoken language processing. Brain Language, 121(3), 273 -288. http: //dx. doi. org/doi: 10. 1016/j. bandl. 2012. 03. 005

References Hickok, G. (2009). The functional neuroanatomy of language. Physics of Life Reviews, 6(3), 121 -143. http: //dx. doi. org/10. 1016/j. plrev. 2009. 06. 001 Mc. Caffrey, P. (1999). Dysarthria at a glance [Fact sheet]. Retrieved June 10, 2013, from http: //www. csuchico. edu/~pmccaffrey//CMSD 642 Study. Guide. pdf Mixed dysarthria. (n. d. ). Retrieved June 10, 2013, from http: //mixeddysarthria. wix. com/mixeddysarthria#! Ogar, J. , Slama, H. , Dronkers, N. , Amici, S. , & Gorno-Tempini, M. L. (2005). Apraxia of speech: An overview. Neurocase, 11, 427 -432. http: //dx. doi. org/10. 1080/13554790500263529 Rilling, J. , & Glasser, M. (2008, March 24). Wired for language. Retrieved June 10, 2013, from http: //news. sciencemag. org/sciencenow/2008/03/24 -02. html

References Robinson, G. , Blair, J. , & Cipolotti, L. (1998). Dynamic aphasia: an inability to select between competing verbal responses? Brain, 121(1), 77 -89. http: //dx. doi. org/10. 1093/brain/121. 1. 77 Rohrer, J. D. , Knight, W. D. , Warren, J. E. , Fox, N. C. , Rossor, M. N. , & Warren, J. D. (2007). Word-finding difficulty: a clinical analysis of the progressive aphasias. Brain, 131(1), 8 -38. http: //dx. doi. org/10. 1093/brain/awm 251 Stem Cell Treatment. (n. d. ). Motor neuron tract [Photograph]. Retrieved from http: //stemcelltreatments. org/wp-content/uploads/2012/01/als-stem -cell-treatment-300 x 237. jpg

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