SLH/LIN 350: Language and the Brain

Vocabulary flashcards generated from the SLH/LIN 350 Language and the Brain lecture notes covering neuroanatomy, neurophysiology, speech genetics, neural oscillations, language networks, and hemispheric lateralization.

Broca's Area

A brain region located in the inferior frontal gyrus responsible for motor speech production and articulation, identified by Paul Broca through his patient Louis Victor Leborgne ('Tan').

Wernicke's Area

A brain region located in the posterior temporal lobe (posterior STG) responsible for language comprehension and processing word meaning, identified by Carl Wernicke.

Gestural-Origin Hypothesis

The theory positing that early humans communicated through physical gestures to express emotions, actions, and ideas before developing spoken language.

Vocal-Origin Hypothesis

The theory proposing that human language emerged directly from vocalizations such as grunts, cries, iconic sound imitations, or mother-infant soothing sounds.

FOXP2 Gene

A gene responsible for producing a transcription factor protein active in language-related brain regions (Broca's area, basal ganglia, and cerebellum), essential for verbal motor control.

KE Family

A large three-generation British family exhibiting a dominant FOXP2 mutation, studied because approximately 50% of its members inherited severe developmental verbal dyspraxia.

Genome-Wide Association Studies (GWAS)

Large-sample statistical studies that scan whole genomes across thousands of participants to discover multiple genetic variants associated with specific traits or disorders.

Microtubules

Parallel protein bundles arranged in axons and dendrites that maintain structural strength and act as tracks for long-distance transport within the neuron.

Pyramidal Neurons

The dominant type of multipolar neuron in the cerebral cortex, including language areas, characterized by triangular somas and prominent apical/basal dendrites.

Neural Oscillations

Rhythmic, repetitive electrical activity generated by synchronized action potential firing across populations of neurons.

Cortical Tracking

The phase-locking of neural oscillations to the temporal acoustic envelope of continuous spoken language.

Delta Oscillations

Neural frequency band ($0.5\text{--}4\,Hz$) that phase-locks to speech at the temporal rate of words, phrases, and syntactic structures.

Theta Oscillations

Neural frequency band ($4\text{--}8\,Hz$) that phase-locks to speech at the temporal rate of syllable production.

Gamma Oscillations

High-frequency neural band ($30\text{--}50\,Hz$) involved in lower-level acoustic encoding of rapid subphonemic and phonetic details.

Cochlear Nucleus

The first central auditory brainstem structure where the auditory nerve from the cochlea enters the brain, preserving sound timing and frequency.

Superior Olivary Complex

A brainstem auditory structure that receives bilateral inputs from cochlear nuclei and processes binaural timing and intensity cues for sound localization.

Inferior Colliculus

A midbrain auditory center that integrates spatial, pitch, and temporal information from both ears before projecting to the thalamus.

Medial Geniculate Body

The auditory nucleus of the thalamus that shapes and relays processed subcortical auditory information to the primary auditory cortex.

Basal Ganglia

A set of subcortical nuclei (caudate, putamen, globus pallidus) involved in coordinating motor movement, procedural learning, and reward-driven behavior.

Limbic System

A group of subcortical structures (including the amygdala, hippocampus, and cingulate cortex) responsible for emotion, memory, motivation, and spatial navigation.

Heschl's Gyrus

The anatomical gyrus located inside the lateral sulcus of the temporal lobe that houses the primary auditory cortex.

Superior Temporal Gyrus (STG)

A key temporal lobe gyrus responsible for sound processing and language comprehension, containing Wernicke's area in its posterior portion.

Key Cortical Language Areas

Major anatomical gyri in the left cerebral cortex that support language, including the Inferior Frontal Gyrus, Supramarginal Gyrus, Angular Gyrus, Superior Temporal Gyrus, and Middle Temporal Gyrus.

Arcuate Fasciculus

A major white matter pathway connecting posterior temporal language areas (Wernicke's) directly to frontal motor speech areas (Broca's).

Frontal Aslant Tract

A white matter tract connecting the supplementary motor area (SMA) to Broca's area, involved in speech initiation and fluency.

Dual-Stream Model

The prevailing model of speech processing proposing two parallel streams: a ventral stream for mapping sound to meaning and a dorsal stream for mapping sound to articulation.

Ventral Stream

The bilateral pathway in the dual-stream model that translates acoustic speech signals into conceptual, lexical, and semantic representations.

White matter tracts: uncinate fasciculus, inferior fronto-occipital fasciculus, inferior longitudinal fasciculus

Dorsal Stream

The left-dominant pathway in the dual-stream model that maps auditory speech representations onto motor articulatory speech networks.

White matter tracts: arcuate fasciculus, superior longitudinal fasciculus

Dichotic Listening

A noninvasive behavioral technique presenting different auditory stimuli to both ears simultaneously to assess hemispheric language dominance.

Right Ear Advantage

The superior performance in dichotic listening for speech sounds presented to the right ear, due to direct contralateral connections to the left language-dominant hemisphere.

Wada Procedure

A surgical mapping procedure where an anesthetic (such as sodium amytal) is injected into a carotid artery to temporarily selectively paralyze one brain hemisphere to determine language dominance.

Split-Brain Patients

Individuals who have undergone surgical transection of the corpus callosum (corpus callosotomy), preventing direct interhemispheric communication.

Medulla Oblangata

Controls heart rate and breathing.

Contains nuclei for hearing, balance/eye movement (vestibular nuclei), and consciousness/arousal (reticular formation).

Pons

Forms a bridge from the cerebellum to the rest of the brain.

Auditory and vestibular nerves exit from the boundary between pons and medulla.

Nuclei for hearing and balance overlap with medulla+pons.

Cerebellum

Important for fine motor control.

Supports reading fluency, language processing. Lesions can affect speech and language: Dysarthria (slurring of speech) and may affect auditory working memory.

Cerebellar disfunction is implicated in developmental dyslexia.

Anterior midbrain

Movement initiation regions (red nucleus + substantia nigra)

Middle midbrain

Pain modulation (PAG)

Posterior midbrain

Sensory regions:
Inferior colliculus (auditory)
Superior colliculus (visual)

Basal ganglia

Coordinates and controls movements.

Implicated in reward learning.

Involved in Parkinson Disease and Tourette Syndrome/motor tics.

Supramarginal Gyrus

Sits above the lateral sulcus and superior temporal gyrus (STG).

Left supramarginalgyrus processes spoken and written words, makes phonological choices, and supports verbal working memory.

The supramarginal gyrus is lateralized (right functions differently).

Angular Gyrus

Helps turn written words into meaning by passing visual information to language processing centers.

Damage here creates issues with reading/writing.

Arches over the superior temporal sulcus.

Middle Temporal Gyrus

Assists with sound recognition and retrieving meaning from memory.

Supports language processing, reading comprehension, and understanding word meanings.

Located just below the superior temporal gyrus.

Wernicke-Geschwind model

1. To hear, speech is sent through auditory pathway to Heschl’s gyrus, then to Wernicke’s area where word meaning is extracted.

2. To speak, word meanings are sent from Wernicke’s area to Broca’s area. The model proposed Broca held representation of words. That information is sent to the motor cortex, then to the facial motor neurons in the brainstem to move facial muscles.

3. To read, written text is sent from the occipital lobe to the angular gyrus, then to Wernicke’s area (for silent reading) and then to Broca’s (for reading aloud).

Frontal aslant tract

Implicated in speech initiation and fluency.

Damage to frontal aslant tract is studied in relation to stuttering.

Combinatorial network

Individual words combine to form larger semantic phrases and syntactic structures.

Anterior middle temporal gyrus (aMTG), anterior inferior temporal sulcus (aITS)

Lexical interface

Links phonological and semantic information.

Posterior middle temporal gyrus (pMTG), posterior inferior temporal sulcus (pITG).

Articulatory network

Maps speech sounds to motor movements for articulation.

Posterior inferior frontal gyrus (pIFG), premotor cortex, anterior insula