Physiological Psychology 2200 Study Guide for Test 1, "Fundamentals of the Brain" Test 1 to be held Tues Sept 22, 2015 *********************************************************************** Anatomy Identify and define parts of neuron –axon, axonal bouton, dendrite, dendritic spines, synapse, synaptic cleft. Know the NS (nervous system) is divided into neurons (transmission) and glia (support). Know the primary types of glia – astrocyte (structural/metabolic support), oligodendrocyte/myelin (insulation). Note, an oligodendrocyte in peripheral NS is called “schwann cell.” Myelin sheath (produced by oligodendrocye and schwann cell) surrounds axons, insulation increases transmission speed of action potential. Node of Ranvier – opening in myelin sheath, allows ion flux and AP transmission Define white matter/grey matter Define pre-­‐synapatic/post-­‐synaptic neuron (with respect to a specific synapse) Define central NS (CNS; brain, spinal cord) versus peripheral NS (PNS; cranial nerves, spinal nerves, autonomic NS). Define blood-­‐brain barrier. Define the 12 cranial nerves by name/function and S or M; know the 4 classes of spinal nerves (based on vertebral sections) – cervical, thoracic, lumbar, sacral. 1
Know the vertebral cross-­‐section of the spine -­‐-­‐ ventral “roots” (axon bundles going out) = motor, dorsal roots (axon bundles going in) = sensory. The “horns” (ventral and dorsal) are where the spinal nerves synapse inside the spinal cord. The dorsal root ganglia holds the cell bodies for unipolar somatosensory neurons bringing info in from the skin. Know 3 Parts of Autonomic Nervous System – 1) sympathetic system (know major functions and anatomical features (nerve regions, ganglia location)); 2) parasympathetic system (again know major functions and anatomical features); 3) enteric system (enervates gut). Know developmental subdivisions of brain – hindbrain/midbrain/forebrain – that emerge in embryonic development from neural tube. Which anatomic structures does each subdivision become (i.e., developmental origins)? 2
Identify planes of section (horizontal, coronal, saggital) Be able to locate in sagittal midline (mid-­‐saggital) view of human brain: Medulla Pons Cerebellum Thalamus Hypothalamus Corpus callosum Neocortex or cerebral cortex Have a basic (general) understanding of ascending functions associated with ascending structures (i.e.brainstem = breathing, heart, movement; cortex = higher thought). Be able to locate in external view of brain and know function for: Occipital lobe (visual cortex) Temporal lobe (auditory cortex including Wernicke’s area) Parietal lobe (somatosensory cortex) Frontal lobe (motor cortex at central sulcus (including Broca’s speech area), higher executive function/decision making towards front /frontal cortex) Know structures of the basal ganglia and limbic system. 3
Fiber tract = bundle of axons (usually myelinated) Know that cerebrospinal fluid (CSF) is in the ventricles of the brain, and spinal CSF is in sub-­‐
arachnoid space of spinal column. These are continuous (connected). Describe language areas of human cortex (i.e., Wernicke’s, Broca’s). Define laterality, e.g., for speech and language. Understand crossed (contra-­‐lateral) sensory pathways. Understand implications of the “split brain” condition and why items presented to one visual field, or one hand, are processed only by the contralateral hemisphere. Be able to assess whether a split brain individual can or cannot verbalize information presented as described (i.e., blindfolded and object held in left hand...). ************************* Development and Evolution Define phylogeny Describe relative measures of brain evolution – total brain weight; brain/body ratio; cortex/hindbrain ratio; index of cerebral enfolding. Understand the phrase “ontogeny recapitulates phylogeny.” Describe neurogenesis -­‐-­‐ ventricular zone is where neural progenitors are “born” and start their migration (derived from stem cells). At core of neural tube, bordering CSF. Also know terms and rough timeline for neuronal migration/differentiation, synaptogenesis, myelination, pruning. 4
Neuroblastoma -­‐-­‐ a form of cancer seen mainly in infants and children, because neurons proliferate prenatally, and cancer is a disorder of cell division (run-­‐away mitosis). Adult neurons no longer divide and replace themselves. Most adult brain cancers are gliomas (glial cells continue to divide in adults) or meningiomas (cancer of the meninges). Radial glia – a developmental form of glia (transient) used by migrating neurons for guidance. Distinguish stem cells (can become anything) from neural progenitors (can only become neurons or glia, but are still “plastic”) from fully differentiated (less plastic) neurons and glia. Understand “neuronal differentiation” and “neuronal plasticity.” Define lamination (layering, e.g. in cerebral cortex) Define neurotrophic factors (promote neural growth), apoptosis (programmed cell death), necrosis (injury-­‐induced call death). Understand sequential processes of: 1) neurogenesis (neuronal proliferation), 2) neuronal migration, 3) neuronal differentiation, 4) synaptogenesis, 5) myelination, 6) pruning. Know relative order of these events. Describe critical aspects of the frontal cortex (part of frontal lobe, which also contains motor cortex) – e.g., most evolved, last to develop, control executive functions and higher-­‐order decision making. Not fully developed in teens (still pruning). ********************** Neurons, Synapses & Transmission Know additional parts of neuron – axon hillock, synaptic vesicles, synaptic cleft, apical dendrite, basilar dendrite. Define excitatory (EPSP) versus inhibitory (IPSP) post-­‐synaptic potential. Glutamate is an “excitatory” neurotransmitter, GABA is an “inhibitory” neurotransmitter. Distinguish projecting neurons (long axons, connect across regions and/or structures, usually myelinated) from inter-­‐neurons (shorter axons, local modulation of other neuronal activity, usually not myelinated). Define membrane diffusion, permeability, transport. Distinguish passive ion channel from transport pump. Which uses ATP (cellular energy)? 5
Describe resting potential in typical neuron -­‐-­‐ where are K+ and Na+ (predominantly)? Cation -­‐-­‐ positively charged ion (like Na+ or K+). Anion -­‐ negatively charged ion (like Cl-­‐). Action potential -­‐-­‐ the all or none depolarization/repolarization that traverses the axon. What is meant by "all or none?" Describe the graded potential changes that can alter the resting potential at the axon hillock: EPSP – causes cations (e.g., Na+) to flow in and post-­‐synaptic neuron becomes more positive (depolarized) – thus MORE likely to fire an AP (action potential). IPSP -­‐-­‐ causes cations (e.g., K+) to flow out and post-­‐synaptic neuron becomes more negative (hyper-­‐polarization) OR anions (e.g., Cl-­‐) can flow in, post-­‐synaptic neuron also becomes more negative (hyper-­‐polarization)) – in either case, LESS likely to fire an AP. Know the typical resting potential (-­‐60mV) and the typical threshold to trigger an AP (about -­‐40 mV). Know the use for the “Nernst/Goldman” equations. These are used to calculate the “differential charge inside versus outside the neuron.” This difference is the “neuron potential,” and is normally quite negative (see Resting Potential). Describe the 5 phases of the action potential: •RESTING potential around -­‐60mV (more or less); •Resting potential hits threshold due to GRADED changes from EPSPs; •Na+ rushes in to rapidly DEPOLARIZE (rising); •K+ rushes out to RE-­‐POLARIZE (falling), with a slight over-­‐shoot (hyper-­‐polarize) •The Na+/K+ pump works to get all the Na+ and K+ back in RESTING state balance. 6
Follow an AP from one neuron to the next – Neuron 1 gets a few EPSPs and depolarizes to threshold (-­‐40mV), thus fires an AP. AP travels down the Neuron 1 axon in a wave of ion flux (Na+ in/K+ out) that jumps the nodes of ranvier, and results in the release of synaptic vesicle(s) from the pre-­‐synaptic (Neuron 1) membrane into the synaptic cleft, BETWEEN Neurons 1 and 2. The transmitter binds to the post-­‐synaptic membrane of Neuron 2, and causes an EPSP or IPSP (depending whether the transmitter is inhibitory or excitatory), by affecting post-­‐synaptic ion channels, and altering post-­‐synaptic ion balance. This changes the likelihood that Neuron 2 will fire its own AP (EPSP, more likely; IPSP, less likely). ****************************************************************** Neuroimaging and Experimental Methods Distinguish case study versus experimental study. Define independent variable, dependent variable, significant difference Define MRI, CAT, MEG, PET, fMRI and TMS methods with full name (what does the abbreviation stand for), and basic descriptions. Know what each of the imaging methods measures: MRI – atomic resonance/energy release CAT – tissue density by X-­‐ray MEG – electromagnetic fields at surface of skull resulting from neural (ionic flux) activity PET – radioactive glucose consumption fMRI – atomic resonance plus BOLD signal (oxygenation) Understand the differences between methods that provide good structural versus functional resolution, and when each method might be appropriate (e.g., clinical or experimental scenarios). Explain what is meant by “subtracting baseline activity” (using control task), in functional neuroimaging (fMRI). Distinguish coma, vegetative state, and locked-­‐in syndrome by presence or absence of awareness (consciousness) and motor arousal (sleep, eyes open, movement). Note the difference between voluntary (conscious; "squeeze my hand") and involuntary (automatic) movements. 7