Biological Bases of Behavior

Biological Bases of Behavior Let’s talk about the brain Biology, Behavior, and Mind Humans are biopsychosocial systems: Everything psychological is simultaneously biological Neural Plasticity the ability of neural networks in the brain to change through growth and reorganizatio...

Biological Bases of Behavior Let’s talk about the brain Biology, Behavior, and Mind Humans are biopsychosocial systems: Everything psychological is simultaneously biological Neural Plasticity the ability of neural networks in the brain to change through growth and reorganization Biology + experience = new pathways as the brain changes and adapts a.k.a. the brain you were born with is not the brain you die with makes the human brain unique  The Neuron It all starts with an individual nerve cell called a neuron.  Parts of the Neuron Synapse The space between the sending neuron and the receiving Nucleus neuron Contains cell’s genetic material Dendrites The branch-like structures that RECEIVE the message from other neurons. Like antennae 5 Cell Body/Soma The life-support center for the cell which contains the NUCLEUS ➔ Contains the cell's genetic material 6 Axon Tail-like structure that passes the message away from the cell body to the axon terminals 7 Myelin Sheath Fatty protective layer that insulates axon and helps to speed up the message 8 Axon Terminals End branches of the axon where the message ends up Form junctions with other cells 9 Terminal Buttons Contain vesicles that hold neurotransmitters 10 Synapse The gap between two neurons that a message is sent Synapse across The space between the sending neuron and the receiving neuron 11 12  Types of Neurons/nerve cells Sensory Motor Interneurons Carry incoming Carry outgoing Within the brain and information from information from spinal cord and the sensory the brain and communicate internally receptors to the spinal cord to the and intervene between brain and spinal muscles and the sensory and motor cord glands outputs aid in reflexes  Neural Transmission Action Potential: A brief electrical charge that travels down its axon Threshold: The level of stimulation required to trigger a neural impulse Refractory Period: A brief pause that occurs after a neuron has fired where the neuron cannot fire again  The order a neuron fires 1 2 3 4 5 Message is Message is Message is The message The message received at sent sent down leaves the enters the the the axon that AXON SYNAPSE and through the TERMINALS DENDRITES CELL is wrapped in awaits to enter the MYELIN through BODY TERMINAL receiving cell or SHEATH reuptake BUTTONS Reuptake: the reabsorption of neurotransmitters into the sending neuron  Nature Neurons!  Neural Transmission Review! ➔ Parts of a neuron ➔ Order of transmission ➔ What is action potential? ➔ What is the refractory period? ➔ What is reuptake? 17 Neurotransmitters These are the chemical messengers of the nervous system! Acetylcholine Function: Enables muscle action, learning, and memory Botox interferes with ACh causing paralysis of those muscles 19 Dopamine Function: Influences feelings of pleasure (reward), mood, movement, motivation. People will repeat behaviors that lead to dopamine release (addiction) Serotonin Function: Affects mood, hunger, sleep, and arousal What we eat, sunlight exposure, and exercise all impacts our levels of serotonin Norepinephrine Function: Helps control alertness and arousal. Involved in fight or flight response. Common ADHD medications affect norepinephrine levels at the neurons synapse GABA Function: A major inhibitory neurotransmitter; calms firing nerves in the nervous system Meditation and mindfulness can increase GABA levels Glutamate Function: A major excitatory neurotransmitter; involved in learning memory. Tomatoes, cheese, mushrooms, and meat can increase levels of glutamate Endorphins Function: Influences perception of pain or pleasure; body’s natural pain killer Released during exercise and excitement; producing well-being and euphoria  How Do Drugs Alter Neurotransmission? The brain may stop naturally producing neurotransmitters Drugs and other chemicals affect brain chemistry at their synapses. Drugs will either amplify or block neurotransmitter activity  Agonist An agonist mimics a neurotransmitters effect on neuron. AGONISTS Morphine, for instance, mimics the action of endorphins by stimulating receptors in the brain areas involved in mood and pain sensation.  ANTAGONISTS An antagonist blocks a neurotransmitters effect on a neuron For example: ○ Black widow bites paralyze a person by blocking Ach receptors involved in muscle movement. ○ Naloxone blocks the effects of opioids and is used when people overdose on opioids  The Nervous System Nervous System Consists of all the nerve cells. It is the body’s “speedy” electrochemical communication system.  Two Parts Central Nervous System Peripheral Nervous System The brain and spinal cord The sensory and motor neurons that connect the central nervous system to the rest of the body Peripheral Nervous System Somatic Nervous System Autonomic Nervous System  Somatic Nervous System Responsible for controlling voluntary activities (eating a hamburger) After the brain processes the info, the somatic neurons respond, and you take action  Autonomic Nervous System Responsible for controlling involuntary activities (heartbeat, digestion, etc.) Has two divisions: Sympathetic Parasympathetic  The Endocrine System Endocrine System: A set of glands that secrete hormones into the bloodstream The body’s “slow” communication system Hormones: Chemical messengers manufactured in the endocrine glands Affect brain and different tissues Testing effect! 1. When a neuron fires an action potential, the information travels through the axon, the axon terminals, the dendrites, and the cell body, but not in that order. Place the structures in order. Dendrites → cell body → axon → axon terminals Testing effect! 2. Serotonin, dopamine, and endorphins are chemical messengers called ____________________. Neurotransmitters Testing effect! 3. ___________neurons carry incoming information from the sensory receptors to the brain and spinal cord Sensory Testing effect! 4.The brain’s ability to change and reorganize after damage or by building new pathways. Neural Plasticity Testing effect! 5. Which system is the “speedy” communication system? Nervous System Testing effect! 6. What are the three types of neurons? 1. Motor neurons 2. Sensory neurons 3. Interneurons Testing effect! 7. What are the two main divisions of the nervous system? 1. CNS 2. PNS  Brain Structure BRAINSTEM The oldest part of the brain Begins where the spinal cord swells and enters the skull Responsible for automatic survival functions (breathing, heartbeat, etc.) BRAINSTEM THE LIMBIC SYSTEM The Limbic System is a doughnut shaped system of structures in the temporal lobe. It’s associated with emotions such as fear, aggression, and drives for food, sleep, and sex. It includes the hippocampus, amygdala, and hypothalamus THE AMYGDALA The Amygdala consists of two lima bean sized neural clusters linked to the emotions of fear and aggression. “Fight or Flight” THE HYPOTHALAMUS Controls HOMEOSTASIS Directs several maintenance activities like hunger, thirst, body temperature, and control of emotions. Helps govern the endocrine system via the pituitary gland. Emotion & reward THE HIPPOCAMPUS Processes conscious, explicit memories & learning Short & Long term Memory Without this you would be unable to develop new memories Testing effect! 1. The three parts of the limbic system are the amygdala, hypothalamus and the A. cerebral hemispheres B. hippocampus C. Frontal lobe D. pituitary gland B Testing effect! -Multiple Choice 2. Which part of the limbic system has to do with fear and aggression? A. Amygdala B. Hippocampus C. Hypothalamus D. Thalamus A Testing effect! 3. The neural structure that most directly regulates eating, drinking, and body temperature is the A. endocrine system B. hypothalamus C. hippocampus D. amygdala B Testing effect! - Multiple Choice 4. Which part of the limbic system has to do with processing conscious, explicit memories? a. Amygdala b. Hippocampus c. Hypothalamus d. Thalamus B Testing effect! 5. The tiny space between the axon of one neuron and the dendrite or cell body of another is called the A. axon terminal B. branching fiber C. synaptic gap D. threshold C  BRAIN DIVISION Cerebrum: ○ Largest part of the brain ○ Contains: cerebral cortex and cerebral hemispheres Cerebellum: ○ known as the “little brain” and is attached to the rear of the brainstem. ○ It helps coordinate voluntary movements and balance. ○ Processes procedural memories.  THE CEREBRAL CORTEX Cerebral Cortex: The layer of interconnected neurons that cover the cerebral hemispheres. Ultimate control and information-processing center of body 20–23 billion neurons and 300 trillion synaptic connections Divided into 4 lobes Cerebral Hemispheres- left & right 61  OUR BRAIN DIVIDED The left hemisphere The right hemisphere processes language, processes imagination, analysis, mathematics, artistic awareness, and comprehension creativity, facial skills recognition, and insight  STRUCTURE OF THE CEREBRAL CORTEX Each brain hemisphere is divided into four lobes that are separated by prominent fissures ○ Frontal Lobe: Forehead ○ Parietal Lobe: Top of head ○ Occipital Lobe: Back of head ○ Temporal Lobe: Side of head  FRONTAL LOBE Controls important cognitive skills: ○ Emotional control ○ Personality ○ Problem solving ○ Reasoning ○ Judgement ○ Memory ○ Speech (Broca’s Area)  PARIETAL LOBE Processes sensory information: ○ Touch ○ Taste ○ Temperature Associated with movement and orientation/position  OCCIPITAL LOBE Visual processing center Distance & Depth Perception Object & Facial Recognition Color Determination Contains Visual Cortex  TEMPORAL LOBE Associated with: Perception and recognition of auditory stimuli Encoding of memory Speech (Wernicke’ Area) Phineas Gage Phineas Gage  Brain Cortex Types The Prefrontal Cortex is the area at the front of the frontal lobe that is known as the “personality center” of the brain. Assists in decision making. Last section to mature (around 25 years old)  Brain Cortex Types The Motor Cortex is the area at the back of the frontal lobe that controls voluntary movements. The (Somato)sensory Cortex receives and processes sensory information including touch, temperature, pain, pressure, position or vibration Homunculus 72  LANGUAGE AREAS Two areas, both in the left hemisphere ○ Broca’s Area: responsible for the production of speech ○ Wernicke’s Area: important for language development and the comprehension of speech  INJURIES TO LANGUAGE AREAS Aphasia: is an impairment of language, usually caused by left hemisphere damage BROCA’S APHASIA BROCA’S APHASIA WERNICKE’S APHASIA  CORPUS CALLOSUM CONNECTS THE LEFT AND RIGHT CEREBRAL HEMISPHERES CORPUS CALLOSUM SPLIT-BRAIN PATIENTS When the corpus callosum is removed or unattached, you have a split-brain patient  SPLIT BRAIN PATIENTS With the corpus callosum severed, objects (apple) presented in the right visual field can be named. Objects (pencil) in the left visual field cannot JOE Testing effect! 1. What four lobes make up the cerebral cortex? Frontal lobe Parietal lobe Occipital lobe Temporal lobe Testing effect! 2. Which brain hemisphere is more analytical. Left Hemisphere Testing effect! -Multiple Choice 3. If a neurosurgeon stimulated your right motor cortex, you would most likely... A. see light B. hear a sound C. feel a touch on the right arm D. move your left leg D Testing effect! -Multiple Choice 4. Studies of people with split brain and brain scans of those with brain damage indicate that the left hemisphere excels in A. processing language B. visual perceptions C. making inferences D. neurogenesis A Testing effect! -Multiple Choice 5. What are the messengers for 1. the nervous system 2. the endocrine system 1. Neurotransmitters 2. Hormones BRAIN PLASTICITY- Jill Bolte Taylor