Brain Anatomy and Function

Parietal Lobes The parietal lobes can be divided into two functional regions. One involves sensation and perception and the other is concerned with integrating sensory input, primarily with the visual system. The first function integrates sensory information to form a single perception (cognition). The second function constructs a spatial coordinate system to represent the world around us. Individuals with damage to the parietal lobes often show striking deficits, such as abnormalities in body image and spatial relations (Kandel, Schwartz & Jessel, 1991). Functions: Location for visual attention. Location for touch perception. Goal directed voluntary movements. Manipulation of objects. Integration of different senses that allows for understanding a single concept. Observed Problems: Inability to attend to more than one object at a time. Inability to name an object (Anomia). Inability to locate the words for writing (Agraphia). Problems with reading (Alexia). Difficulty with drawing objects. Difficulty in distinguishing left from right. Difficulty with doing mathematics (Dyscalculia). Lack of awareness of certain body parts and/or surrounding space (Apraxia) that leads to difficulties in self-care. Inability to focus visual attention. Difficulties with eye and hand coordination. Temporal Lobes Kolb & Wishaw (1990) have identified eight principle symptoms of temporal lobe damage: 1) disturbance of auditory sensation and perception, 2) disturbance of selective attention of auditory and visual input, 3) disorders of visual perception, 4) impaired organization and categorization of verbal material, 5) disturbance of language comprehension, 6) impaired long-term memory, 7) altered personality and affective behavior, 8) altered sexual behavior. Functions: Hearing ability Memory aquisition Some visual perceptions Catagorization of objects. Observed Problems: Difficulty in recognizing faces (Prosopagnosia). Difficulty in understanding spoken words (Wernicke's Aphasia). Disturbance with selective attention to what we see and hear. Difficulty with identification of, and verbalization about objects. Short-term memory loss. Interference with long-term memory Increased or decreased interest in sexual behavior. Inability to catagorize objects (Catagorization). Right lobe damage can cause persistant talking. Increased aggressive behavior. Occipital Lobes The occipital lobes are the center of our visual perception system. They are not particularly vulnerable to injury because of their location at the back of the brain, although any significant trauma to the brain could produce subtle changes to our visual-perceptual system, such as visual field defects and scotomas. Functions: Vision Observed Problems: Defects in vision (Visual Field Cuts). Difficulty with locating objects in environment. Difficulty with identifying colors (Color Agnosia). Production of hallucinations Visual illusions - inaccurately seeing objects. Word blindness - inability to recognize words. Difficulty in recognizing drawn objects. Inability to recognize the movement of an object (Movement Agnosia). Difficulties with reading and writing. Cerebellum The cerebellum is involved in the coordination of voluntary motor movement, balance and equilibrium and muscle tone. It is located just above the brain stem and toward the back of the brain. It is relatively well protected from trauma compared to the frontal and temporal lobes and brain stem. Functions: Coordination of voluntary movement Balance and equilibrium Some memory for reflex motor acts. Observed Problems: Loss of ability to coordinate fine movements. Loss of ability to walk. Inability to reach out and grab objects. Tremors. Dizziness (Vertigo). Slurred Speech (Scanning Speech). Inability to make rapid movements. Brain Stem The brain stem plays a vital role in basic attention, arousal, and consciousness. All information to and from our body passes through the brain stem on the way to or from the brain. Like the frontal and temporal lobes, the brain stem is located in an area near bony protrusions making it vulnerable to damage during trauma. Functions: Breathing Heart Rate Swallowing Reflexes to seeing and hearing (Startle Response). Controls sweating, blood pressure, digestion, temperature (Autonomic Nervous System). Affects level of alertness. Ability to sleep. Sense of balance (Vestibular Function). Observed Problems: Decreased vital capacity in breathing, important for speech. Swallowing food and water (Dysphagia). Difficulty with organization/perception of the environment. Problems with balance and movement. Dizziness and nausea (Vertigo). Sleeping difficulties (Insomnia, sleep apnea).