Our Incredible Nervous System Module 4 Our Incredible Nervous System

Development and Functioning What influences our brains? Evolution Birth defects Brain Damage Genetic defects

Study of the Living Brain MRI (magnetic resonance) highlights different areas of the brain fMRI (functional MRI) highlights the active neurons as the brain thinks PET (positron emmission tomography) These allow us to understand what parts of the brains have different functions, and where damage has occured

Organization of the nervous system Central Nervous System: Brain and spinal cord Carries information between the brain and the body Peripheral Nervous System: Nerves that extend from the spinal cord to carry messages to and from the muscles, glands and sense organs

Subdivisions of the Peripheral nervous system Somatic Nervous System: Nerves connected to sensory receptors or voluntary muscles (ie neck, back, limbs) Afferent (sensory): nerve fibers carry information to the spinal cord/brain from sensory receptors Efferent (motor): nerve fibers carry information from the brain/spinal cord to the muscles

Subdivisions of the Peripheral nervous system (con’t) Autonomic Nervous System: Regulates heart, breathing, blood pressure, digestion, mostly involuntary actions 2 parts: Sympathetic and Parasympathetic

Subdivisions of the Peripheral nervous system (con’t) Sympathetic Nervous System Triggered by threatening/challenging stimuli, increases physiological arousal and prepares body for action Parasympathetic Nervous System Returns body to calmer, relaxed state and is involved with digestion Homeostasis means these two systems work together to keep arousal balanced for optimal functioning

Comparing the Systems Sympathetic Parasympathetic Pupils dilated/dry Eyes Dry Mouth Goosebumps Skin Sweaty Palms Increased rate heart Pupils constricted/moist Salivation Smooth Dry Decreased rate

Igor - where is my brain???? Get into your head …

Major parts of the brain Forebrain - hemispheres involved in thinking,learning,memory, spoeech and language, emotions,sensations, voluntary movement, planning and decisions Midbrain - reward/pleasure centre stimulatedby food, sex, money, music, attractive faces and drugs: visual and auditory reflaxes, and reticular formation to process sensory information Hindbrain - Pons, Medulla and Cerebellum

Major brain stuff, continued Pons: bridge for messages from the spinal cord to brain, also makes sleep chemicals Medulla: controls vital reflexes such as breathing, heart rate and blood pressure Cerebellum: coordinates motor movements (but does not initiate them), timed motor movements, and reflexive learning

The Cortex and 4 Lobes of the brain

The Cortex Wrinkled surface of the brain Majority of neurons found here Wrinkled to fit many many cells into a small space (paper analogy) Has four different functional lobes

Frontal Lobe Huge area of cortex Interprets and performs emotional behaviour, dictates social behaviour,basis of personality,makes decisions, plans and pays attention to environment Contains motor cortex, which controls voluntary movements Executive control: like boss of a company

Parietal Lobe Processes sensory information from body parts: touch, location of body in space,temperature sensing and pain, and cognitive functions such as attention to and perception of objects. Also involved in language abilities Includes somatosensory cortex, which processes sensory information from the body: found next to the motor cortex

Temporal Lobe - 4 parts Involved in hearing, speaking coherently, understanding verbal and written material Primary Auditory Cortex transforms info from ears into sound sensations Auditory Association Area takes those sensations and makes them recognizable (ie words/music) Broca’s Area combines sound into words and arranges them meaningfully (actually in frontal lobe) Wernicke’s Area is necessary from speaking coherent sentences and understanding speech

Occipital Lobe processes visual information including seeing colour and perceiving and recognizing animals, people and objects Primary Visual Cortex is at the very back, receives electrcal signals from receptors in the eye and changes them to basic visual sensation (ie light, shadow, texture) Visual Association Cortex interprets the basic sensations into complete meaningful perceptions such as people, objects or animals

- Broca’s Asphasia Wernicke’s Asphasia Visual Agnosia Neglect Syndrome

The Limbic System (old!) Core of the forebrain Regulates motivational behaviour such as obtaining food drink and sex; stores memories; also organizes emotional behaviours such as fear, anger and aggression

Endocrine System

Endocrine System This system is made up of many glands throughout the body, which secrete various chemicals called hormones which affect organs, muscles, and other glands. The Hypothalamus controls much of this system by regulating the pituitary gland

Are Men and Women Really Different? men & women Problem Solving Emotional Memories Movement and Coordination

Parts of Limbic System Hypothalamus: regulates motivational behaviour, emotional behaviour and secretion of hormones Amygdala: evaluates emotional significance of stimuli and facial expression Thalamus:receives sensory information and relays it to different areas of the cortex Hippocampus: puts fleeting memories into permanent storage in different areas of the brain

Functions of Hemispheres Verbal – left Mathematical – left Analytic – left Self recognition – left Nonverbal – right Spatial – right Holistic – right Other recognition - right