MU

Neuro lecture 3- 9/3/25

Scheduling, Interviews, and Assessment Logistics

  • In the next 2 weeks there are two main items to watch for via email:
    • Audiology program is hiring for a faculty member.
    • Two faculty members will be on campus for on-campus interviews (on different days: Thursday/Friday for one, Monday/Tuesday for the other).
  • On-campus interviews involve meeting many people and giving a presentation; it is exhausting and you’re expected to be “on” for two days.
  • You’ll interact with people whose decision-making power on your application you may not fully know.
  • It’s important to attend these events because you get a real chance to provide feedback on the instructors, and your feedback is taken incredibly seriously.
    • Feedback forms are provided after meetings and presentations; they are read very carefully.
  • If you have conflicts with the interview schedules, communicate early so you can attend the sessions that affect your experience as a student and potential teacher.
  • Practical takeaway: this is your chance to influence your learning environment for the next two years (at least). Attend and provide constructive feedback.

Quiz and Exam Schedule; Prep Strategy

  • Quiz due Friday; it covers substantial material, including book content.
  • Study tip: read the book and consider tabbing it to locate sections quickly; there is a lot of content.
  • Quiz format: you have 70 seconds for each question (some questions are matching).
  • The quiz design mirrors preparation for the Praxis case (case-style questions).
  • If you have a major meltdown or struggle with questions:
    • Talk to the instructor; this is practice one.
    • If you can’t understand the questions or can’t locate material, bring those concerns up.
  • Next week: start labeling practice; the exam one will include labeling on the material.
  • Week after next: another quiz.
  • The following week: the exam.
  • Instructor commitment: you will be told exactly what is on the exams; if you forget, you should remind the instructor.
  • Administrative notes: attendance sheet and related paperwork; instructor will send vocal tract exercises and stroboscopy materials; take a few minutes to scan those materials.

Core Concepts: Cerebral Cortex and Lateralization

  • The class revisits the brain’s structure and function; emphasis on understanding how things can go wrong and how that affects assessment.
  • Right hemisphere vs left hemisphere functions:
    • Right hemisphere: melody and prosody support production of speech; prosody helps the left hemisphere move words out.
    • Therapy implications: debatable, with some emphasis on personality vs. structural reasons for deficits.
  • The brain is organized into gyri (ridges) and sulci (valleys). The bumpy surface underlies functional specialization.
  • Gyri/sulci and their responsibilities differ by region; we will discuss lobes and specific gyri within them.
  • Central sulcus (Rolandic fissure): separates motor cortex (anterior) from sensory cortex (posterior).
  • Primary motor cortex and somatosensory cortex are key landmarks for motor and sensory representation.

Frontal Lobe: Executive Functions, Language, and Development

  • Frontal lobe roles include higher-level cognition and executive functions: reasoning, planning, and other complex cognition.
  • Prefrontal cortex (the most frontal part) is the last to develop; development continues into the mid-20s for many individuals.
  • Neuroplasticity: not about replacing functions but refining neural networks; the brain remains plastic during adulthood.
  • Practical implication: injuries to the frontal lobe can impair executive functions, impulse control, planning, and social behavior.
  • Personal anecdote: a patient with frontal lobe injury (Christmas Eve case) showed initial impulsivity and difficulty with executive tasks; over days, family and coworkers observed changes in behavior and decision-making.
  • Expressive language in the frontal lobe: involvement in language production and fluency; apraxia of speech may arise from premotor cortex involvement and often co-occurs with other motor speech disorders.
  • Clinical takeaway: when assessing patients with frontal injuries, consider both motor planning and higher-order cognitive impacts on communication and safety.

Language and Aphasia: Expressive vs. Receptive Language and Case Examples

  • Expressive language and motor planning vs. comprehension:
    • Grace’s video transcript shows pauses, repetition, and limited information processing – illustrating expressive and prosodic features.
    • Grace’s transcript demonstrates how prosody and fluency can be impacted by lateralized speech networks.
  • Sarah’s expressive aphasia example:
    • Post-stroke, Sarah could produce some words but had limited fluency and still-choppy output; she used rote/automatized language and stayed on-topic when possible.
    • Her ability to stay on topic and respond to questions depended on task demands and cueing; some responses were on-topic but limited in content.
    • In cases of temporal lobe involvement, comprehension is affected; a lesion in the temporal lobe can disrupt language comprehension and word meaning integration.
  • Global aphasia concept:
    • If a lesion extends across both frontal and temporal lobes, a severe language impairment occurs (global aphasia): both production and comprehension are profoundly affected.
    • When assessing, clinicians may rely on nonverbal cues or alternative communication methods (e.g., pointing to pictures) to evaluate understanding.
  • Wernicke's area and auditory processing:
    • Wernicke’s area (temporal lobe, near the auditory cortex, sometimes referred to in older literature with various spellings) is critical for language comprehension.
    • The term for the auditory cortex is often associated with Heschl’s gyrus; in the transcript it’s referred to as Heckel’s gyrus (note: standard term is Heschl’s gyrus).
    • The nondominant hemisphere also contributes to processing nonverbal and prosodic aspects of language.
  • Acquired language disorders terminology:
    • Alexia: difficulty reading; Agraphia: difficulty writing.
    • Acalculia: difficulty with numerical calculation; related to parietal-temporal regions and higher-order numerical processing.
    • Dyslexia as a developmental term is sometimes debated in clinical contexts; the lecture emphasizes acquired forms (alexia, agraphia) as opposed to developmental dyslexia.
  • Receptive language vs. expressive language in aphasia:
    • Receptive deficits involve understanding language (comprehension) and can be present even when fluent speech remains, depending on lesion location.
    • Expressive deficits involve producing language (word finding, fluency, and articulation) and can occur with relatively preserved comprehension in some cases.
  • Case vignette cues and testing challenges:
    • When testing, consider that some patients rely more on visual supports (pictures) or nonverbal cues to communicate.
    • In rehab settings, clinicians must adapt testing to sensory capabilities (e.g., lighting, ability to move hands) to complete assessments.
  • Nonverbal perception deficits (non-language deficits) may accompany language disorders, especially with right-hemisphere involvement.

Temporal Lobe: Language Comprehension and Auditory Processing

  • Temporal lobe responsibilities include expressive language features tied to word meaning and concept labeling; language comprehension is a core function.
  • Wernicke’s area is located in the temporal lobe near the auditory association areas and is essential for understanding language; damage results in comprehension deficits.
  • Auditory processing and phoneme discrimination are critical early steps in language understanding; lesions can impair phoneme discrimination and comprehension of spoken language.
  • Non-dominant hemisphere contributions:
    • Auditory processing and processing of nonverbal aspects of language (prosody, intonation) have a significant right-hemisphere component.
  • Atypical language presentations can occur with temporal lobe damage; e.g., a patient might hear sounds but fail to extract meaningful language from them due to comprehension impairment.
  • Clinical nuance: language comprehension relies on integrating sounds with culturally learned labels and concepts; comprehension is not just “hearing sounds” but mapping sounds to meaning.
  • Visual and cross-modal input:
    • When comprehension is severely impaired, clinicians may rely on visual supports and picture-based tasks to assess understanding.
    • The integration of visual processing with auditory language supports can be necessary for some patients with global aphasia or predominant receptive deficits.
  • Heschl’s gyrus and auditory cortex proximity:
    • Language comprehension depends on auditory processing areas in the temporal lobe, including the region around Heschl’s gyrus.

Parietal Lobe: Space, Sensation, and Higher-Order Skills

  • Parietal lobe functions include determining where the body is in space and where objects are in relation to the body.
  • Sensory cortex (somatosensory) sits posterior to the central sulcus; the sensory strip encodes sensation from the body, including tactile information.
  • Tactile agnosia:
    • The inability to identify objects by touch alone despite intact sensation, often requiring integration with other senses to identify items.
  • Higher-order language functions like reading and writing (orthographic processing) also involve the parietal region; this includes laterality and language integration for orthographic tasks.
  • Alexia and agraphia may involve parietal-lobe processes, especially when combined with temporal lobe damage; acalculia ties to numerical processing regions rather than purely language areas.
  • Visual-spatial and visuomotor integration:
    • The parietal lobe helps coordinate movement in space and object interactions; it contributes to how we reach for and manipulate objects (e.g., hitting or avoiding objects).
  • Reading and writing (orthographic processing):
    • The parietal lobe supports higher-level literacy functions, including decoding and recognition of written symbols.

Occipital Lobe: Visual Processing and Related Deficits

  • Occipital lobe is primarily responsible for processing visual information; visual processing supports reading and balance, among other functions.
  • Calcarine sulcus is a key landmark in the occipital lobe; it helps define primary visual cortex boundaries.
  • Visual field deficits:
    • Hemianopsia (hemianopia) is loss of half of the visual field in both eyes; visual processing damage can also lead to visual agnosias where recognition relies more on touch or other senses.
  • Visual agnosia:
    • Inability to recognize objects visually despite intact vision; may rely on touch or other cues to identify objects.
  • Cortical blindness and processing disorders:
    • Cortical blindness occurs when the brain cannot process visual information even though the eyes are functional.
  • The occipital lobe’s role in reading and balance ties into broader neurological and rehabilitative considerations.

Insula and Medial Surface Structures

  • Insula: a deeply located, less-understood region with diverse proposed roles; ongoing research continues to reveal its functions.
  • Medial surface view highlights important structures such as the cingulate gyrus and corpus callosum; this view is critical for understanding inter-lobe communication and integration.
  • Corpus callosum: the major commissural tract connecting left and right hemispheres; movement of information across hemispheres is essential for coordinated function.
  • Medial view illustrates how lobes are connected; understanding this view helps interpret clinical deficits across multiple regions.

Basal Ganglia and Motor Control; Thalamus-Cortex Interactions

  • Basal ganglia play a crucial role in stabilizing movement and coordinating motor plans; it interacts closely with the thalamus and cortex.
  • Pathway overview: Cortex initiates a motor plan → sends signals to the thalamus and basal ganglia → basal ganglia modulates signals (excitatory vs. inhibitory input) → thalamus relays refined motor plan back to cortex → execution of movement.
  • Parkinson’s disease example: lesions in the basal ganglia (notably substantia nigra) impair movement inhibition, leading to bradykinesia and tremor features; the cortex normally sends an instruction, but inhibition is compromised.
  • Essential tremor vs. Parkinsonian symptoms: essential tremor can involve basal ganglia circuits but is not exclusively linked to Parkinson’s disease; both involve motor control pathways.
  • Conceptual takeaway: basal ganglia help regulate how much effort and how long a movement lasts; dysfunction can cause chorea or unwanted movements; movement may be under- or over-controlled or poorly timed.
  • Teaching stance: big-picture understanding first (major structures) before delving into fine details; emphasize big principles over memorizing every minutia.
  • Clinical implication: many conditions in rehab involve complex, multi-lobe involvement; assessments must consider cross-lobe interactions and compensatory strategies.

Landmarks, Imaging, and Visual Aids for Neuroanatomy

  • Important landmarks to identify on diagrams and scans:
    • Sagittal sulcus (longitudinal fissure)
    • Central sulcus (fissure of Rolando)
    • Lateral sulcus (Sylvian fissure)
  • Acceptable synonyms: you may see either term for each landmark; know which terms pair together.
  • Insula: deeper structure with still-emerging understanding; not always visible on surface views.
  • Medial surface slices reveal the corpus callosum, cingulate gyrus, and other midline structures; these views help connect across lobes.
  • Imaging example: functional MRI (fMRI) can illustrate active brain areas during tasks; a bonus slide shows a visible corpus callosum region and surrounding gyri with activation patterns.
  • Practical note: when identifying landmarks in real patients or imaging, be mindful of individual anatomical variation.

Clinical Vignettes and Illustrative Points

  • Grace and Sarah vignettes illustrate real-world manifestations of aphasia and language disorders:
    • Grace: pauses and repetitions indicating prosodic and language retrieval aspects.
    • Sarah: expressive aphasia with some word-finding deficits; attempts at staying on topic and linking responses to questions; reliance on context and cueing.
  • Global aphasia vignette: breakdown of comprehension and expression when damage spans frontal and temporal regions; emphasizes the need for alternate communication strategies.
  • Right-hemisphere nonverbal perception: a rehab patient reported auditory misperceptions (e.g., interpreting environmental sounds as something else) due to right-hemisphere processing.
  • Practical clinical takeaway: when assessing communication disorders after CNS injury, you must consider motor planning, language comprehension, prosody, nonverbal cues, and cross-modal processing.

Practical Implications, Ethics, and Real-World Connections

  • Ethical/practical implications: student feedback on instructors is valued; participating in hiring processes and giving constructive feedback informs future teaching quality.
  • Real-world relevance: concussions and neurodegenerative conditions commonly involve frontal and temporal regions; knowledge of these networks informs diagnosis and rehabilitation planning.
  • Neurodevelopmental considerations: frontal lobe development continues into the mid-20s; neuroplasticity can refine functions but not necessarily replace lost ones.
  • Case-based learning emphasis: use a mix of clinical anecdotes and anatomical knowledge to reinforce understanding and to prepare for exams that combine structure with function.
  • Exam and study strategy across topics:
    • Focus on big-picture concepts first (lobes, major gyri/sulci, major pathways).
    • Understand how deficits arise from lesion locations and how this informs assessment and rehab.
    • Use visuals (diagrams, MRI images) to anchor anatomical knowledge and to practice identifying landmarks.

Quick Reference: Key Terms to Memorize (in Brief)

  • Gyri and sulci: brain ridges and grooves; functional localization varies by region.
  • Central sulcus: separates primary motor cortex (anterior) from primary somatosensory cortex (posterior).
  • Sylvian fissure (lateral sulcus): separates temporal lobe from frontal and parietal lobes.
  • Calcarine sulcus: landmark in the occipital lobe for primary visual cortex.
  • Wernicke’s area: language comprehension (temporal lobe region near auditory cortex).
  • Broca’s area: language production (frontal lobe region).
  • Alexia/agraphia: acquired reading/writing deficits.
  • Acalculia: arithmetic calculation deficit.
  • Hemianopsia/visual field deficits: loss of vision in half the visual field.
  • Global aphasia: severe impairment in both language production and comprehension due to extensive left-hemisphere damage.
  • Apraxia of speech: motor speech disorder where the brain has difficulty coordinating the articulators despite having the intention and physical ability to speak.
  • Basal ganglia: motor control, initiation, and inhibition; linked to Parkinsonian symptoms when damaged.
  • Thalamus: relay and integration hub for motor and sensory information toward the cortex.
  • Corpus callosum: major interhemispheric connection allowing cross-talk between hemispheres.
  • Insula: deep brain region with evolving understanding of its functions.
  • Heschl’s gyrus: primary auditory cortex adjacent to auditory processing areas (temporal lobe).
  • Midsagittal views: medial brain structures (e.g., corpus callosum, cingulate gyrus) and their role in integration across lobes.