Psychology Chapter 3 and 5.pdf

Chapter 3: Biology and Neuroscience ➔ Neurons are cells specialized for communication ➔ Dendrites receive messages and initiate electrical activity ➔ Axons conduct electrical activity and release ➔ The myelin sheath speeds up electrical activity Neurons can be classified by their function ● Sens...

Chapter 3: Biology and Neuroscience ➔ Neurons are cells specialized for communication ➔ Dendrites receive messages and initiate electrical activity ➔ Axons conduct electrical activity and release ➔ The myelin sheath speeds up electrical activity Neurons can be classified by their function ● Sensory neurons carry information to the brain. ● Motor neurons carry information from the brain to the muscles. ● Interneurons convey the signals around the nervous system. Neurons can be classified by their shape ● Multipolar neurons have many dendrites ● Bipolar neurons have one dendrite and one axons ● Monopolar neurons have only one projection from the some, which branches to form the axon and the dendrite ● End of axon terminals are terminal buttons. ● Synaptic vesicles are bubbles containing neurotransmitters (green dots) ● Synaptic cleft or synapse is fluid-filled space between neurons. ● 321 NoKiA for 3 Na out, 2 K in, 1 ATP used How neurons transmit messages: More detail on the Action Potential 1. Na+ ions enter through Na+ channels (influx) and depolarize cell to threshold voltage 2. Voltage sensitive Na+ channels open = lots more Na+ 3. Massive positive ion (K+) efflux a. Leaving cell through K+ channels How Neurotransmitters and Receptors Work Excitatory (exciting) (causing positive (+)) ● Increases probability of neuron becoming active 1. 2. 3. 4. Acetylcholine (Ach) Glutamate Serotonin Dopamine Inhibitory (inhibiting) → Hyperpolarization ● Decreases probability of neuron becoming active 1. Gamma-aminobutyric acid (GABA) 2. Glycine 3. Dopamine Your Brain on Drugs A. Agonist: drug replicates receptor action B. Antagonist: drug prevents receptor action C. Direct: drug binds at same site D. Indirect: drug binds at different site Glial Cells ➔ Glial cells provide physical and metabolic support to neurons, including neuronal insulation and communication, and nutrient and waste transport - Oligodendrocytes are the myelinating cells of the central nervous system (CNS). - They are the end product of a cell lineage which has to undergo a complex and precisely timed program of proliferation, migration, differentiation, and myelination to finally produce the insulating sheath of axons Nervous System Brain Anatomy: How to Build a Sophisticated Network - Neural networks are how dendrites and axons of neurons connect: Central nervous system (CNS) Peripheral nervous system (PNS) → Efferents are axons that carry electrical impulses from CNS to PNS → Afferents are axons that carry electrical impulses from PNS to CNS Central versus Peripheral Nervous System 2 Major Divisions 1. Central Nervous System (CNS) a. Brain b. Spinal cord 2. Peripheral Nervous System (PNS) a. Ganglion: a collection of neuronalbodies found in the voluntary and autonomic branches of the peripheral nervous system (PNS) b. Nerve ● Nerves facilitate communication with/control of the body ○ Efferents and afferents ● Command center with information superhighway ➔ Somatic nervous system controls voluntary movement ➔ Autonomic nervous system controls involuntary functions Somatic Nervous System: Voluntary Movement Includes nerves that connect to muscles and joints in: 1. Neck 2. Arms 3. Legs 4. Torso The Autonomic Nervous System: Automatic Movement Human Nervous System Sections of the Brain: The Central Command Center 4 major lobes of the brain in the central nervous system 1. 2. 3. 4. Frontal lobe Parietal lobe Temporal lobe Occipital lobe ➔ Each lobe performs specific set of functions ➔ Myelinated axons connect ◆ Different brain areas ◆ Brain to body ➔ Brain receives input from body Reticular Activating System (RAS) ➔ Reticular Activating System (RAS) → The RAS connects to the spinal cord and cortical circuits (inhibitory and excitatory ◆ Helps to regulate awareness and attention ◆ Coordinates several brain areas ➔ People process many stimuli ◆ Need this system to focus on what is important! The Coordinators ➔ Limbic system neurons help store emotional memories ➔ If we remove amygdala of a rat, then rat no longer shows fear responses to threats ➔ Amygdala involved in fear Coordinating Movement ➔ The cerebellum communicates with different brain areas to coordinate movement and thought Thalamus: The Relay Station ➔ Clusters of neurons in the thalamus relay sensory information Neocortex (New brain): Higher-level processing - 1 Your cortex is layered ➔ Neocortex is an intricate network of networks ➔ Cortical neurons from each layer have axons that connect designated areas ➔ Association cortices are parts of neocortex ◆ Helps us use sensory information in a meaningful way Three features of the neocortex 1. Gyri (ridges) 2. Sulci (valley) 3. Fissures (spaces between lobes) Frontal Lobes: Executive Decisions ➔ Frontal lobes make decisions and movement ➔ Prefrontal cortex decides when, why, and how to complete actions (connected with frontal lobe) ➔ Motor cortex performs voluntary movement (muscles) Neocortex (New brain): Higher-Level Processing - 2 ➔ Parietal lobes process numbers and perform calculations ➔ Corpus callosum connects two hemispheres of brain and shares information ➔ Occipital lobes process visual information Temporal Lobes: Listen to the Memories Temporal lobes coordinate the formation of new memories Neurons in these lobes process: a. Auditory (hearing) information b. Olfactory (smell) information The Endocrine System ➔ The hypothalamus regulates pituitary (growth and development), temperature, and reproduction ➔ The nervous system helps to control the endocrine system (glands and hormones) ➔ Hypothalamic-Pituitary-Adrenal (HPA) Axis: ◆ Activated in time of stress ◆ How the brain affects immune system Research Methods in Neuroscience Functional Magnetic Resonance Imaging (fMRI) ➔ Uses magnetic fields to image alignments of hydrogen ions ➔ Can measure brain region activation during a task or following stimulation Positron Emission Tomography (PET) ➔ Uses an ingested radioactive compound to track molecular changes ➔ Can visualize the activity of specific neurotransmitters Summary 1. The primary function of the nervous system is to create behavior, and these behaviors are shaped in response to the environment 2. Neurons are the basic building blocks of the nervous system; they send, receive, and relay messages to and from various parts of the body using electrical and chemical processes, which is why we say the language of the brain is “electrochemical". 3. Neurons are made up of many parts, with the most important for neural transmission being the dendrites, the some, the axon, and the terminal buttons. a. Dendrites receive excitatory and inhibitory messages from other cells, and in concert with the soma determine how frequently a cell “fires” an action potential. 4. Action potentials travel along the length of a neuron, allowing for electrical to be sent quickly; myelin speeds this transmission along. a. When an action potential reaches the terminal buttons, neurotransmitters are released into the synaptic cleft and act on the postsynaptic cell. 5. Despite neurons’ critical role in communication a. Glial support cells like astrocytes, microglia, and oligodendrocytes are every bit as important to the function of the nervous system. 6. Neurons control the flow of electrical activity and produce action potential by regulating the presence of ions on either side of the cell membrane; this is accomplished through the use of ion channels 7. Neurotransmitters are the chemical component of the electrochemical ‘language of the brain’; they play important roles in regulating mood, pleasure, movement, memory, and more. (excitatory or inhibitory → psychoactive drugs modulate effectiveness of neurotransmitters) 8. Chapter 5: Sensation & Perception How we understand our environment - Sensations - Features of environment used to create understanding of the world - Perception - Combination of sensations arriving from sensory system and prior knowledge Transduction - Process where sensations are translated to electrochemical transmission of the brain “Typoglycemia (a portmanteau of typo and hypoglycemia) is a neologism for a purported discovery about the cognitive processes involved in reading text. The principle is that readers can comprehend text despite spelling errors and misplaced letters in the words.” - Bottom-up processing - Processing physical messages to delivered to senses - Sensory information - Typoglycemia - Top-down processing - Integrating beliefs, memories, and expectations into sensory experiences to create perception. The Principles of Gestalt Fundamental organization of information - Principle of figure-ground Principle of proximity Principle of similarity Principle of closure Principle of good continuation Principle of common fate