Neuroanatomy & Physiology of Speech

Central Nervous System

Composed of:

• Brain

• Spinal cord

Contains:

• Relays neurons (interneurons)

Peripheral Nervous System

Composed of:

• Cranial nerves

• Spinal nerves

• Peripheral nerves

Contains:

• Sensory neurons

• Motor neurons

Neuron Anatomy

Parts

• Soma

• Dendrites

• Axon

• Myelin Sheath

• Synapse

Neural Transmission

Describes action potential and synaptic transmission

Frontal Lobe

• Motor control

• Broca’s area (speech production)

• Executive functions

Parietal Lobe

• Somatosensory input

• Spatial Processing

Temporal Lobe

• Auditory Processing

• Wernicke’s Area here (Language comprehension and speech production)

Occipital

Vision

Limbic

• Emotion

• Memory

• Includes hippocampus

White Matter Tracts

• Association tracts (Within hemisphere)

• Projection fibers (cortex to lower brain/spinal cord)

• Commissural fibers (between hemispheres)

Basal Ganglia

Role: Movement of coordination, initiation of motor programs

Dysfunction: Stuttering, speech timing issues

Brainstem

Connects brain and body

Dysarthria

Speech disorder caused by muscle weakness (Problems with execution)

Symptoms:

• Slurred speech

• Speaking slowly

• Talking too fast

• Difficulty moving tongue, lips, jaw

• Voice changes

Apraxia

Difficulty with motor planning and programming

Symptoms:

• Groping

• Inconsistent errors

• Difficulty initiating articulatory sequences (disrupted fluency)