ANATOMIA FUNCIONAL DO CÓRTEX - PARTE 2

Anatomy of the Functional Cortex

Overview of Tertiary Association Areas

• The lecture concludes with a focus on tertiary association areas, starting with the prefrontal area located in the non-motor part of the frontal lobe.

• The prefrontal area includes Brodmann areas 9, 10, 11, and 46, connecting to various brain structures such as the brainstem and thalamus.

• This area integrates inputs from multiple regions including the basal nuclei, cerebellum, reticular formation, hypothalamus, hippocampus, and unimodal areas.

Functions of the Prefrontal Area

• The prefrontal cortex is crucial for judgment, decision-making, inhibition of socially inappropriate behaviors, creativity, and motivation.

• Specifically highlighted is the dorsolateral prefrontal area (Brodmann areas indicated in blue), which plays a role in planning and executing behavioral strategies based on social contexts.

Orbital Prefrontal Area

• The orbitofrontal area is located medially on the frontal lobe's surface and is involved in emotional processing and attention maintenance.

• It connects with basal nuclei circuits and contributes to suppressing undesirable behaviors while maintaining focus.

Posterior Parietal Area

• Transitioning to posterior parietal areas (Brodmann areas 39 and 40), this region encompasses parts of the inferior parietal lobe including supramarginal gyrus.

• Its primary function involves integrating sensory information from auditory and visual modalities to form complete mental images of objects.

Importance of Body Awareness

• The posterior parietal area aids in spatial perception and body schema awareness—how individuals perceive their own bodies within space.

Understanding Electrical Stimulation and Muscle Contraction

Overview of Muscle Contraction and Electrical Stimulation

• The discussion begins with the concept of electrical current and its role in muscle polarization, leading to muscle contraction.

• The presentation includes a focus on pelvic floor muscles, highlighting the connection between these muscles and patient exercises aimed at enhancing contraction.

• Data is presented comparing pre- and post-intervention measurements, showing significant changes in pressure readings across different groups (G1, G2, G3).

• Group 1 exhibited a notable reduction in pressure from 34 cm to 26.14 cm after interventions, indicating a relative decrease of 71%.

• The study suggests that using anatomical figures alongside electrical stimulation can improve body awareness and benefit patients with urinary incontinence or other pelvic dysfunctions.

Implications for Patient Treatment

• Patients experiencing issues such as urinary incontinence or anal continence may find relief through targeted strategies involving electrical stimulation.

• The findings indicate an important increase in muscle strength and performance following the interventions discussed.

Neuroscience Insights: Anterior Insular Cortex Functions

Anatomy and Functionality of the Anterior Insular Cortex

• Transitioning to neuroanatomy, the anterior insular cortex's location is described along with its structural classification as isocortex homotypic.

• Key functions include empathy, self-awareness regarding one's own physiology compared to others, emotional perception, and subjective experiences related to emotions.

Limbic System Connections

• Discussion expands on limbic structures involved with emotional processing; this includes deep temporal lobe structures like the hippocampus.

Language Processing Areas: Broca's and Wernicke's Areas

Broca’s Area: Language Expression

• Broca’s area is identified as crucial for language expression—both spoken and written—located within the opercular and triangular parts of the inferior frontal gyrus.

• Damage to this area results in motor aphasia where individuals understand language but struggle to express themselves verbally.

Wernicke’s Area: Language Comprehension

• Wernicke’s area plays a vital role in language comprehension; it processes auditory information related to speech.

• This area connects semantically with Broca’s area for effective communication; understanding precedes response formulation.

Understanding the Role of Brain Structures in Language Processing

The Fasciculus Longitudinalis Superior and Its Importance

• The discussion begins with the Fasciculus Longitudinalis Superior, a crucial fiber bundle in the brain that connects various language-related areas.

• Lesions in this fasciculus or specific language areas can lead to significant disturbances, impacting both sensory and motor aspects of language.

Types of Aphasia: Broca's and Wernicke's Areas

• Broca's Area lesions result in motor aphasia, characterized by difficulties in speech production, leading to expressive aphasia.

• In contrast, damage to Wernicke's Area leads to sensory aphasia, where individuals may produce fluent but nonsensical speech, indicating a lack of comprehension.

Characteristics of Sensory and Motor Aphasia

• Individuals with sensory aphasia can speak but fail to understand questions, often responding with irrelevant statements.

• Conversely, those with motor aphasia understand questions but struggle to express their thoughts verbally due to impaired output mechanisms.

Neural Pathways Involved in Language Processing

• Information from visual stimuli (via photoreceptors) and auditory stimuli (via cochlear nerve) is processed through distinct pathways leading to the thalamus.

• The thalamus acts as a relay center for both auditory and visual information before projecting it to the primary sensory cortex.

Integration of Sensory Information into Language Production

• The primary sensory cortex is linked with secondary unimodal areas responsible for interpreting detailed information from sensory inputs.

• These secondary areas project information to Wernicke’s area for processing before being relayed to Broca’s area for speech production.

Influence of Basal Ganglia on Speech Production

• Broca’s area receives input from basal ganglia which influences its function; however, it does not directly connect with lower motor neurons responsible for speech articulation.

Understanding Cortical Function Asymmetry

Primary Motor Areas and Projections

• The primary motor area in the cortex projects to the brainstem via the corticobulbar tract and to the spinal cord through the corticospinal tract, influencing lower motor neurons.

• These lower motor neurons connect with effector organs, specifically muscles, illustrating a simplified diagram of how responses are linked.

Hemispheric Structure and Communication

• The brain consists of two hemispheres: the right and left cerebral hemispheres, separated by a significant fissure known as the longitudinal fissure.

• Interhemispheric communication occurs through commissural fibers, primarily the corpus callosum, along with other structures like the anterior commissure and fornix.

Dominance of Cortical Functions

• There are asymmetries in cortical functions indicating that one hemisphere may dominate certain tasks; for most individuals, this is typically the left hemisphere.

• Key areas such as Broca's area (speech production) and Wernicke's area (language comprehension) are predominantly located in the dominant hemisphere.

Implications of Hemispheric Dominance

• Damage to specific areas in the dominant hemisphere can lead to conditions like aphasia or motor dysfunction due to their localized functions.

• For instance, an infarction in the left middle cerebral artery can result in expressive language deficits if it affects Broca’s area.

Characteristics of Left vs. Right Hemisphere

• The left hemisphere is associated with logical reasoning, analytical thinking, and language skills—often described as practical and structured.

• In contrast, the right hemisphere is linked to creativity, emotional expression, sensory experiences, and abstract thinking—characterized as imaginative and free-spirited.

Assessing Lateralization Through Dominance Tests

• Lateralization can be observed through activities such as writing or sports; individuals tend to use their dominant hand or foot for these tasks.

Dominance and Lateralidade in Neurodevelopment

Understanding Manual Skills and Dominance

• The speaker discusses the relevance of testing in understanding manual skills, emphasizing its interesting nature.

• There is a focus on how dominance may manifest throughout neurodevelopment, particularly through the expression of lateralidade (laterality).

• The speaker indicates that these observations are significant for understanding developmental processes.