Biosci 1 Revision PDF

Iden fy the cerebellum, medulla oblongata, and frontal lobe in a brain image and recall the func on of the brain area. Func ons:  Frontal lobe responsible for execu ve func on; Func ons to help you plan, organize, manage me, avoid saying or doing the wrong thing...

Iden fy the cerebellum, medulla oblongata, and frontal lobe in a brain image and recall the func on of the brain area. Func ons:  Frontal lobe responsible for execu ve func on; Func ons to help you plan, organize, manage me, avoid saying or doing the wrong thing  medulla oblongata is to help a person breathe.  Cerebellum: controls coordina on, balance and posture. Helps with cogni ve func ons like a en on, language and fear memory.  Parietal Lobe: helps with a en on, language, interpre ng sensory informa on like pain and touch. Helps iden fy special rela onships.  Occipital Lobe: vision, including recognizing shapes and colors  Temporal Lobe: helps with hearing, language, reading, short term memory and smell recogni on  Cerebrum: controls conscious and unconscious behaviors, feelings, intelligence and memory.  Thalamus: Relay center for the sensory systems Apply principles of deducing brain func on from loss-of-func on lesion studies to iden fy the func on of a new brain area. If a part is removed, what func on is lost? Recall the brain connec on disrupted in lobotomies and deduce the behavioral effect of lobotomies. Lobotomies sever the connec on between the en re frontal lobe to the thalamus. Lobotomies were:  Quick Severed the thalamus from the frontal lobe Widely given to stop psychosis and children’s temper tantrums Some mes calmed psychosis but also made pa ent mentally dull Shameful part of neuroscience history Dis nguish Broca’s area from Wernicke’s area. Broca’s area contains neurons involved in speech func on. This area of the brain acts as a command center, orchestra ng the complex muscle movements necessary for ar cula ng spoken words. To form words and sentences, Broca's area must relay signals to coordinate the muscles of the lips, tongue, and throat. Wernicke’s area func ons in language comprehension and our ability to understand the words. Propose a behavioral test to determine whether Broca’s area or Wernicke’s area was affected. Remember: IT’S NOT JUST ABOUT THE REGIONS BUT THE CONNECTIONS HOW BRAIN REGIONS ARE CONNECTED REFLECT THE BRAIN REGION’S FUNCTION. OVERARCHING PRINCIPLE: A STRUCTURE'S PHYSICAL CHARACTERISTICS INFLUENCE ITS INTERACTIONS WITH OTHER STRUCTURES, AND THEREFORE ITS FUNCTION. STRUCTURE → FUNCTION Provide example of how brain imaging or recordings of brain ac vity can predict responsiveness to an depressants. Currently, brain imaging is not reliable for diagnosis. However, brain ac vity can predict responsiveness to an depressants. Increased rostral anterior cingulate cortex (rACC) theta ac vity linked to be er an depressant (sertraline) outcome. (Rostral is the part closest to the nostril.) Describe how selec ve serotonin reuptake inhibitors (SSRI), serotonin norepinephrine reuptake inhibitors, and monoamine oxidase inhibitors affect neurotransmission and how they are thought to treat depression according to the monoamine hypothesis of depression. SERTALINE (SOLD AS THE TRADE NAME ZOLOFT) INCREASES SEROTONIN IN THE BRAIN - Serotonin is a type of neurotransmi er. Serotonin is released into synapse (the space between two neurons). - Neurotransmi ers are the main type of chemical messenger in the brain. They are released from one neuron to communicate with a second neuron. - Neuropep des are another type of chemical messenger. Pep des are much larger than neurotransmi ers. - Both neuropep des and neurotransmi ers are involved in chemical transmission. This differs from electrical transmission. Monoamine Hypothesis of depression: Predicts that the “underlying pathophysiologic basis of depression is a deple on in the levels of serotonin, norepinephrine, and/or dopamine in the central nervous system.” This theory has been ques oned. Symptoms to diagnose depression:  Depressed mood most of the day, nearly every day.  Markedly diminished interest or pleasure in all, or almost all, ac vi es most of the day, nearly every day.  Significant weight loss when not die ng or weight gain, or decrease or increase in appe te nearly every day.  A slowing down of thought and a reduc on of physical movement (observable by others, not merely subjec ve feelings of restlessness or being slowed down).  Fa gue or loss of energy nearly every day.  Feelings of worthlessness or excessive or inappropriate guilt nearly every day.  Diminished ability to think or concentrate, or indecisiveness, nearly every day.  Recurrent thoughts of death, recurrent suicidal idea on without a specific plan, or a suicide a empt or a specific plan for commi ng suicide Iden fy the axon, axon terminal, cell body, dendrite, and dendri c spines in a cartoon neuron & describe the general func on of each. Dendri c Spines: Typically where neurons receive messages from other neurons Axon Terminals: Typically where neurons send messages to other neurons. The size of an axon depends on the neuron. The longest axon in your body is the scia c nerve. The sensory fibers in the scia c nerve begin at your big toe and ends at the base of your spinal cord. Iden fy the range of axon lengths in the human body. The length of axons in the human body varies greatly depending on the type of neuron and its func on, ranging from a frac on of a millimeter to over a meter. Dis nguish exocytosis and endocytosis. CYTO = CELL ENDO = INTO EXO = EXIT Exocytosis is a cellular process in which substances are released via vesicles. Endocytosis is a cellular process in which substances are brought in via vesicles. Dis nguish the effects of Botox and loss of dynamin, and describe the mechanism of ac on. Botox inhibits vesicles from fusing to the plasma membrane by inhibi ng snare proteins. What does botox do to neural transmission? A) blocks endocytosis b) blocks exocytosis c) enhances endocytosis d) enhances exocytosis Dynamin mutants are missing a protein called dynamin. In these mutants, the vesicles cannot split from the plasma membrane. What happens to synap c transmission? A) blocks endocytosis b) blocks exocytosis c) enhances endocytosis d) enhances exocytosis Dynamin mutants have ____________________. Vesicles can fuse to the plasma membrane, but are stuck at the plasma membrane. Electrophysiology is the branch of science that studies the electrical ac vity of neurons. It is used to measure synapse func on. A er postsynap c receptors are ac vated, reuptake transporters recycle neurotransmi ers. Exocytosis and endocytosis recycle membrane, but reuptake transporters recycle neurotransmi ers. Describe how current is carried in a neuron. AFFERENT VS. EFFERENT Efferent: informa on flows from the brain and spinal cord; motor informa on afferent: informa on flows to the brain and spinal cord; sensory informa on Dis nguish depolariza on from hyperpolariza on. Hyperpolariza on is when the membrane poten al becomes more nega ve at a par cular spot on the neuron’s membrane, while depolariza on is when the membrane poten al becomes less nega ve (more posi ve). Depolariza on and hyperpolariza on occur when ion channels in the membrane open or close, altering the ability of par cular types of ions to enter or exit the cell. Describe the sequen al steps in an ac on poten al and how this affects depolariza on and hyperpolariza on. During an ac on poten al, the opening and closing of V-gated K+ and Na+ channels are well med. DRAW THE SHAPE OF AN ACTION POTENTIAL STEP 1: Na+ channels open STEP 2: K+ channels open STEP 3: a er a delay, Na+ channels inac vate, helping K+ channels to hyperpolarize membrane poten al. Define membrane poten al and determinants of membrane poten al. Electrical impulses going through a neuron are due to differences in ion concentra ons resul ng in a voltage difference, called a “poten al”. The difference in electrical charges inside and outside a cell creates a voltage difference. We call this a: MEMBRANE POTENTIAL. The membrane separates the inside and outside of a cell. Even when a neuron is at rest, there is a voltage difference across the membrane. We call this RESTING MEMBRANE POTENTIAL. When an electrical impulse is traveling down a neuron, we call this the ACTION POTENTIAL. Traveling electrical impulses are called electrical current. Name a drug that affects the ac on poten al. Tetrodotoxin ( x) blocks voltage-gated sodium channels. Botox inhibits vesicles from fusing to the plasma membrane by inhibi ng snare proteins. Provide a neurochemistry examine of how energy and ma er cannot be created or destroyed, but can be changed from one form to another. Provide counterarguments which propose that the monoamine hypothesis of depression is wrong. Iden fy two key components of the mesolimbic pathway of the “reward center.” See Lecture 7 Describe an experiment that shows that dopamine serves as a reward predic on-error signal. Recall Adrian Raine’s findings about the brains of impulsive murderers. He found....a reduc on of gray ma er in the prefrontal cortex. WHITE MATTER: composed of white myelinated axons GRAY MATTER: composed of unmyelinated cell bodies A loss of cell bodies in the prefrontal cortex means: LESS REGULATION of the amygdala (the emo onal control center for the brain). REDUCED ABILITY to regulate emo ons on a moment by moment basis. DIFFICULTY dealing with emo ons DIFFICULTY deciphering when it’s appropriate to express emo ons Describe how the prefrontal cortex modulates anger mediated by the amygdala and hypothalamus. THE PREFRONTAL CORTEX CAN MASK ANGER MEDIATED BY THE AMYGDALA AND LOWER BRAIN REGIONS HYPOTHALAMUS Regulates fear, thirst, sexual drive, sleep and aggression AMYGDALA Influences our mo va on, emo onal control, fear response and interpreta ons of nonverbal emo onal expressions Iden fy the experiments which showed a ack neurons are specific to the ventrolateral hypothalamus and that these neurons are sufficient and necessary for aggression. In 2013, the Skoll World Forum gathered experts to talk about the science and anthropology of aggression. ac va on of these neurons using channelrhodsin is enough to cause aggressive behavior. ( See Lecture 7, slide 24) optogene c ac va on of vmhvl causes this mouse to behave violently. optogene c silencing of vmhvl with halorhodopsin causes this mouse to stop violent behavior HALORHODOPSIN EXPERIMENTS SHOW: ATTACK NEURONS in the VMHvl are necessary to elicit aggression. If a ack neurons are necessary, it means that aggression cannot occur without a ack neurons. SUFFICIENCY VS. NECESSITY If something is SUFFICIENT for a func on, it means it is enough to perform the func on. If something is NECESSARY for a func on, it means without it, you can’t perform the func on. Example: Ea ng is necessary but not sufficient for survival...you also need water, oxygen, etc. To test if something is sufficient, we need to ac vate and To test if something is necessary, we need to inac vate the neuron. Iden fy the experiments which showed social experience, specifically social isola on, increases aggressive behavior. Fly study showed expression of the gene Cyp6a20 had less aggression. SOCIAL EXPERIENCE, ESPECIALLY SOCIAL ISOLATION, INCREASES AGGRESSIVE BEHAVIOR Flies raised in social isola on are very aggressive. Flies raised in groups are rela vely placid. Note: Just because genes are involved in behavior does not mean the behavior is immutable or determinis c. Describe rela ve loca ons of brain regions using the anatomical reference points of: anterior/posterior, dorsal/ventral, lateral/medial, rostral/caudal. Iden fy the amygdala in brain images and as the hub of emo onal processing. AMYGDALA Influences our mo va on, emo onal control, fear response and interpreta ons of nonverbal emo onal expressions. Explicit emo onal processing: Conscious, declara ve evalua on of emo onal states Implicit emo onal processing: Unconscious, automa c processing of emo onal s muli examine brain images from individuals while they are performing the task look for informa on about loca on of brain ac vity & rela ve ac vity at different mes of the task. Define sensory transduc on. SENSORY TRANSDUCTION: Convert various forms of energy located outside of the body (e.g. light rays, sound waves, mechanical forces, or chemicals) into neural signals. Explain how conforma on change in re nal is responsible for light detec on. SENSORY TRANSDUCTION: Convert light rays (specifically photons) located outside of the body into neural signals. THE PHOTORECEPTORS ARE IN THE RETINA ZOOM, REALLY ZOOM INTO THE YELLOW LAYER PICTURED IN THE PREVIOUS SLIDE the photoreceptor is a neuron. two types of photoreceptors rod and cones. Rods are very sensi ve and cones are less sensi ve in dim ligh ng. Rods and cones are unfairly distributed in the re na. Rhodopsin molecules in outer segment of a photoreceptor undergoes conforma onal change when struck by a photon. Classify rhodopsin, transducin, and hyperpolariza on as either G- protein coupled receptor, G-protein, or downstream effect of G- protein cascade. See Lecture 9, slide 22. Provide example of how structure informs func on in the visual system. Describe unequal distribu on of rods and cones on the re na and how different photoreceptor densi es affect vision. Trace how objects in visual space are represented in the re na, a er the op c chiasm and in the visual cortex (V1). Dis nguish the func on of the dorsal stream from the ventral stream. Evaluate which stream is defec ve in akinetopsia, prosopagnosia, or a new medical condi on. Determine which s mulus would best ac vate neurons in the fusiform face area. Dis nguish how the grandmother cell coding scheme differs from the popula on coding scheme in use of neurons, efficiency, and accuracy. (See Lecture 11, slide 3-6) Iden fy what sensory transduc on must be deciphered in the auditory system. Sound waves push hair cells. Mechanoreceptors on hair cells detect the movement and trigger more or less ac on poten als based on the direc on of movement. The cochlea in the inner ear detects sound waves. Sensory Transduc on: All biological sensors must solve the problem of sensory transduc on. It converts various forms of energy located outside of the body (like light rays, sound waves, mechanical forces, or chemicals) into neural signals. Sensory Transduc on: In hearing, it converts sound (specifically pressure waves in the air) located outside the body into neural signals. Provide an example of how structure informs func on in the auditory system. the ac vated part of the cochlea then sends ac on poten als to the primary auditory cortex The spiral configura on of the cochlea allows for differing frequencies to s mulate specific areas along the spiral, which results in a tonotopic map that enables humans to perceive various frequencies of sound. It's filled with fluid that moves in response to sound waves and is split into three tubes by two thin membranes. One of these membranes — the basilar membrane — is like an elas c wall, on top of which sits the organ of Cor. Hair cells in the cochlea are organized as a tonotopic map. A map where the neurons are tuned to the similar sound frequencies that are located adjacent to one another. Describe the tonotopic map in the cochlea and auditory cortex. (See Lecture 11, slide 17) The number refers to sound frequency. A higher number equates to a higher frequency. The ear also houses the ves bular system. It is not part of the hearing system, but it gives you your self of balance. Describe the rela onship between calcium carbonate crystals and ves bular hair cells to ver go. (See Lecture 12, slide 7) A MISFIRING VESTIBULAR SYSTEM IN VERTIGO Calcium carbonate crystals that become stuck will overac vate hair cells. Even when the head is upright and sta onary, the calcium carbonate crystals collide with ves bular hair cells. The brain receives constant neural impulses that the body is upside down or falling when in actuality the body is sta onary. In contrast, the working ves bular system works as follows: Includes 3 semicircular canals filled with gela nous membrane infused with thousands of calcium carbonate crystals. When the head moves, the calcium carbonate crystals collide with ves bular hair cells. This bends the ves bular hair cells, causing the cells to depolarize. Iden fy the five basic tastes and examples of each.  Umami: Japanese for delicious. The flavor of glutamate, the G in MSG. It is savory. Examples are cheese, mushrooms, poultry, pork, beef.) Sweet: Salty: Bi er: Sour: Describe differences, if any, between the expression pa erns of taste buds responsible for different tastes. (See Lecture 14, Slides 3- 6 and Lecture 12, slides 12-20) There are different taste buds expression pa erns. Classify T1R1, T1R2, T1R3, T2R, gustducin, TRP-M5, and TRP-M4 as either G-protein coupled receptor, G-protein, or TRP channel. Recall the order in which they are ac vated in the gustatory system. (See Lecture 14, slides 3-10) T1R1, T1R2, T1R3 and T2R: G-Protein coupled receptors Gustducin: G protein TRP-M5 and TRP-M4: Trip channels Taste receptors: are G protein coupled receptors (CPCRs). The taste receptors ac vate the TRP channels. Gustducin: The name of the G protein coupled to the receptors. At the end of the protein cascade, TRP-M5 or TRP M4 channels are open. gustatory cortex: a hub of mul sensory integra on including connec ons to the reward centers of the brain. Describe characteris cs of TRP channels. (Lecture 14, slide 8-9) TASTE RECEPTORS ACTIVATE TRP CHANNELS. TRP channels = Transient receptor poten al channels (pronounced “trip channels”) When open, it produces a short depolariza on (posi ve poten al) Non-selec ve ca on channels Ac vated through diverse mechanisms! EXAMPLES: chemicals, temperature, light, sound, touch Explain why anosmia is common a er car accidents. Loss of smell (anosmia) is common a er whiplash. Delicate olfactory nerves entering ver cally through the cribriform plate are severed. Analyze pa erns of odorant receptor ac va on involved in odor detec on. (Lecture 14, slide 17-19) HOW DO OLFACTORY NERVES DETECT CHEMICAL ODORANTS? Via the Olfactory bulb (region in the brain). The olfactory bulb is part of the Central Nervous System (CNS). The olfactory nerves detect chemical odorants. Chemical Odorants are ligands. 3. Signals are sent to the olfactory bulb. 2. Olfactory nerves are bundles of neurons (labeled olfactory receptor cells in this picture). 1. Olfactory cells have olfactory receptors (a type of protein). An odor ac vates a specific combina on of receptors. Some odorants only ac vate a combina on of one receptor. Different odorants can ac vate the same receptors. SENSORY TRANSDUCTION (Lecture 14, slide 21) EXTERNAL STIMULI RECEPTOR Vision Rhodopsin (a protein) on photoreceptor (a cell) Sound Hair cell (a cell) Sweet Tastant T#R# heterodimer (2 proteins) on a taste cell Odor Combina on of receptors (proteins) on an olfactory cell Describe the chemotopic map and dis nguish it from the re notopic map, tonotopic map (and homunculcus). CHEMOTOPIC MAP: Structurally similar odorants s mulate overlapping but dis nct domains in the olfactory bulb. See Lecture 14, slide 25 Capsaicin: the ac ve ingredient in chili peppers. Hydrocarbon chains make this chemical compound nonpolar. Nonpolar molecules do not dissolve well in polar solu ons like water. Polar and nonpolar molecules separate from each other. It is the ac ve ingredient in pepper spray. Nocicep on: ability to feel pain, caused by s mula on of a nociceptor Capsaicin binds TRPV1 A type of transient receptor poten al ion channels TRPV1 receptors respond to heat and produce burning pain sensa ons TRP channels are gated by temperature and various chemical ligands agonist: drug that mimics endogenous ligand and ac vates receptor (lecture 14, slide 34) antagonist: drug that blocks endogenous ligand or agonists from ac va ng receptor