The Brain and Behavior
The Basic Structure of the Nervous System • The Neuron Dendrites Cell Body Axon Hillock Axon Nodes of Ranvier Myelin Sheath Axon Terminals Synaptic Vesicles Synapse • Glial Cells Myelination
The Glial Cells • Functions of Glial Cells There are 9-times more glial cells than neurons in the brain.They communicate with neurons and each other about the messages traveling among neurons. They can alter signals at the synapse and influence where synapses are formed. They may be critical in forming memories and repairing nerve damage and play a major role in diseases like Alzheimer’s and Parkinson’s.
The Neural Impulse • The direction of the Action Potential is always left to right. When the neuron is not firing it is in Resting Potential. • Neurons have either excitatory or inhibitory influence on each other.
The Synapse Electrical Synapse Chemical Synapse
Biochemistry • Neurotansmitters • Neurohormones • Neuromodulators • Neuropeptides • The Lock & Key Theory • The Classical Biochemicals Acetylcholine GABA Dopamine Glutamate Serotonin (5-HT) The Endorphins Epinephrine Norepinephrine
Biochemical Effects Nervous System Chemicals & Their Effects Type Function Effects Where Produced Examples Neurotrans- Enable neurons to Diverse, depend- Brain, spinal cord, Serotonin, mitters excite or inhibit ing on which peripheral nerves, Dopamine, each other circuits are act- certain glands Norepinepherine ivated or sup- pressed Endorphins Usually modulate Reduce pain, pro- Brain, spinal cord (Several varieties) the effects of mote pleasure; of neurotrans- also linked to mitters learning, memory & other functions Hormones Affect function- Dozens, ranging Primarily in the Epinephrine, nor- ing of target from promotion endocrine glands epinephrine, organs & tissues of digestion to estrogens, regulation of androgens metabolism
Biochemical Interactions Pleasure Drive Appetite, Sex, Aggression Motivation Cognitive Function, Mood, Emotion Fight – or - Flight Health Functions, Growth & Well-Being, Homeostasis Anxiety, Irritability
The Effects of Drugs • Drugs increase or decrease the action of the neurotrans-mitters at the synapse Some (e.g. cocaine) stop reuptake, others take the place of specific neurotransmitters.
Nervous System Organization of the
The Brain The Brain contains between 100 Billion & 1 Trillion Neurons with more than 1000 Synapses per Neuron.
Brain Scan The Brain Processes About 400 BILLION Bits of Information At A Time. We're Aware of Only About 2000 Bits.
Left Hemisphere The Analytic Hemisphere. Dominant in most people. Interprets actions, moods, & thought processes. Constructs theories about actions & feelings, & tries to bring order & unity to our conscious lives. It is specialized for language in 95% of right-handed & 75% of left-handed. Makes causal inferences. Solves problems via established methods & well-ordered plans. Right Hemisphere The Synthetic Hemisphere. Specialized in facial recognition. Has its own consciousness. Perceives melodies, patterns, & analyzes nonverbal patterns. Judges grammatical correctness of a sentence. It is holistic and has limited language skills. Has a larger volume of an “association cortex” for complex information pro- cessing. It makes leaps of insight. Beginning at the Top
Corpus Callosum • The fibers connecting the left and right hemispheres of the brain. • Contralateral Control The left hemisphere controls the right side of the body and the right hemisphere controls the left side of the body. What purpose does Contralateral Control serve?
The Central Core • The Hindbrain Consists of: The Medulla, the Pons, and the Cerebellum • The Midbrain Consists of: The Thalamus, the Hypothalamus, and the Reticular Formation
The Limbic System • Considered the “Seat of the Emotions” • Consists of: Thalamus Hypothalamus Hippocampus Olfactory Bulb Amygdala
Receives Sensory Input from the Joints, Muscles, Bones, Skin, Touch, Pressure, Pain, & Internal Organs The Cerebral Cortex Encodes, Stores, & Recalls Sequences; Processes Serial Order Information Within the Context of a Motor Task; Recognizes & Remembers Sequence of Events in Time. Word Production & Grammatical Processing; Semantic Analysis; Motor Patterns for Speech Production Attention to Details; Visual & Auditory Words; Discriminates Familiar & Un- familiar Stimuli; STM for Abstract Symbols; Sentence Memory; Visual Orienting; Concentration; Shifting of Attention The Cerebral Cortex is the outer "Gray Matter" & the "Association Areas." Working Memory; Word & Speech Perception (Left); Visual & Auditory Words; Associates Words; Analysis & Meanings of Items; Self-Analysis; Object Identity; Recognizes Facial Features; Action Plans Organizes Visual Information; Activates &Processes Color, Shape, &Motion; Creates Visual Images; Maps & Analyzes Visual Information; Processes Visual Words Listening to Words; Working Memory; Processes Words Visually & Auditorially; Visual Computation & Motion; Primary Auditory Cortex; Monitors Speech; Generates Verbs; Speech Output Understanding & Expression of Language; Listening to Words; Semantic Analysis & Interpretation
The Computer Operates Sequentially. Has Open and Closed Gates. Processes information very quickly. Components of the computer are reliable but removing 1 or 2 can disrupt processing. Each gate receives a single input and sends that input on. Recognizes only precise input. The Brain Operates sequentially and in parallel. Has Open, Closed, and Almost Gates. Processes information slowly. Neurons are somewhat unreliable, but deletion of quite a few is not likely to make a major difference in behavior. Neurons receive input from thousands of other neurons and connects to thousands of other neurons. Recognizes patterns. The Brain/Computer Connection
The Endocrine System • The Major Glands Called “the glands of personality” in the early 20th century. Thyroid Gland Parathyroid Glands Pineal Gland Pancreas Pituitary Gland Posterior & Anterior Gonads Adrenal Glands
Pineal Gland • Secretion: Melatonin Functions: Reproduction & Sleep-Wake Cycles Low Melatonin: Insomnia High Melatonin: Decreased Motor Activity, Fatigue, & Lower Body Temperature
Pituitary Gland • Secretions: Posterior Lobe: Oxytocin, Vasopressin, & Antidiuretic Hormone Anterior Lobe: Hormones Include Thyroid-stimulating Hormone, ACTH, FSH, & Prolactin Affects growth and the other glands
Thyroid Gland • Secretions: Thyroxin & Triiodothyronine Regulates Metabolism
Parathyroid Gland • Secretion: Parathyroid Hormone Controls Calcium Levels High Calcium Levels: Low Energy Lack of Concentration Depression Irritability Forgetfulness Decreased Sex Drive
Adrenal Glands • Secretions: Epinephrine & Norepinephrine Regulates Energy Levels & Electrolite & Fluid Balance, Kidney & Sexual Function High Epinephrine: Headaches Excess Sweating Tachychardia Anxiety & Nervous Shaking Nausea Weight Loss
Pancreas • Secretions: Insulin, Glucagon, & Somatostatin Controls Blood Sugar & Glucose Metabolism & Digestive Secretions
Reproductive Glands • Ovaries Secretions: Estrogen, Progestrone, & Androstenedione Function: Oogenesis • Testes Secretions: Testosterone & Other Androgens Function: Spermatogenesis Low Testosterone: Decreases Sex Drive High Testosterone: Heightened Bisexuality