Neuro

Brain Structure and Function Overview

Hemispheres and Lobes

  • The brain consists of two hemispheres divided by the corpus callosum.

  • Each hemisphere has four lobes:

    • Frontal Lobe:

    • Responsible for:

      • Motor cortex

      • Speech formation

      • Personality traits

      • Short-term memory

      • Decision-making and problem-solving abilities

      • Judgment processes.

    • Full development typically occurs in young adulthood, influencing behavior and decision-making.

    • Example of frontal lobe injury effects:

      • Chronic Traumatic Encephalopathy (CTE) is linked to decision-making issues seen in football players.

    • Parietal Lobe:

    • Involved in cross-sensory processing and tactile sensations.

    • Key functions include:

      • Pain and temperature sensation

      • Recognition of body parts.

      • Proprioception (awareness of body position in space).

    • Development observed in infants as they gain awareness of their own hands.

    • Temporal Lobe:

    • Primarily located over ears; functions include:

      • Processing auditory information

      • Understanding tastes and smells

      • Maintaining balance

      • Behavioral response and understanding speech and written language.

      • Long-term memory functions differ from those of the frontal lobe.

    • Occipital Lobe:

    • Main function is related to visual processing.

Other Brain Structures

  • Cerebellum:

    • Coordinates muscle tone, balance, and posture.

  • Diencephalon:

    • Location of cranial nerves I and II.

    • Structures include the thalamus and hypothalamus:

    • Thalamus: processes sensory and motor information; regulates awareness.

    • Hypothalamus: oversees autonomic nervous system functions and temperature regulation.

    • Example of autonomic dysregulation: "storming" during brain injuries can result in elevated temperatures without fever.

  • Brain Stem:

    • Divided into multiple sections:

    • Midbrain: contains cranial nerves III and IV; responsible for auditory and visual reflexes.

    • Pons: involves cranial nerves V through VIII, including pupillary reflex.

    • Medulla: governs cranial nerves IX through XII and the respiratory center.

  • Spinal Cord:

    • Extends from the base of the skull to the first lumbar vertebra; does not extend to the end of the spine.

    • Functions:

    • Receives sensory information from skin, joints, and muscles (contains motor neurons).

    • Categorizes nerve pathways:

      • Descending Tracts: convey messages from brain to muscles (e.g., moving from point A to B).

      • Ascending Tracts: relay sensory information back to the brain (e.g., responses to physical stimuli).

Dermatomes and Reflexes

  • Dermatomes:

    • Areas of skin connected to specific spinal nerve fibers; crucial for sensory perception.

    • Example: Shingles can manifest along a dermatome due to nerve inflammation.

  • Deep Tendon Reflexes:

    • Involuntary responses indicating intact nervous system function.

    • Require adequate nerve function and healthy muscles.

Development Through Life Stages

Infants

  • Significant brain development occurs in the first year;

  • Motor activity assessment at birth is vital to monitor reflexes:

    • Key reflexes include:

    • Rooting

    • Moro (startle) reflex.

    • Infants develop motor control from the head downward.

    • Assessment through play is beneficial due to lack of responsiveness to commands.

    • Critical Period: 90% of brain development occurs before age 5; potential impacts from concussions necessitate preventative measures.

  • Typical milestone: walking by the age of one, with some variance up to fifteen months.

Pregnant Individuals

  • Experience of headaches is common, particularly tension headaches during the third trimester due to physical changes and pressure on the spine.

  • Potential for nerve-related pain, such as sciatica during pregnancy.

Older Adults

  • Age-related changes:

    • Decrease in cerebral neurons by approximately 1% per year after age 50; impacting response times but not overall intelligence.

    • Common challenges include fatigue and changes in gait due to spinal compression events.

Neurological Issues and Assessments

Common Reasons for Neurological Consultations

  • Seizure occurrences (triggered by fever, trauma, or increased ICP).

  • Pain, gait issues, signs of weakness, and confusion/disorientation.

  • Mental health concerns, including depression, affect assessments and diagnoses.

  • Historical data of past neurological events: concussions, traumatic brain injuries, strokes, meningitis.

  • Evaluating risk factors: hereditary disorders (e.g., neurofibromatosis, Huntington’s) and developmental disabilities.

  • Environmental hazards (e.g., lead exposure) significantly affect children's neurological development:

    • Lead from sources like paint and plumbing can lead to cognitive issues.

  • Special attention on elderly patient care to include questions on their Activities of Daily Living (ADLs), assistive devices, sleep patterns, substance use, and vaccinations (e.g., meningitis vaccination).