PSY 223: Exam 1 Study Guide
PSY 223: Exam 1 Study Guide psy 223
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This 13 page Study Guide was uploaded by Emily.nicole on Sunday November 1, 2015. The Study Guide belongs to psy 223 at Syracuse University taught by C. White in Summer 2015. Since its upload, it has received 61 views. For similar materials see intro to cognitive Neuroscience in Psychlogy at Syracuse University.
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Date Created: 11/01/15
Topics 4. Methods ● How do they work? ● What do they measure? ● Pros/Cons ● Which should be used?ical (b/w) Cognition: higher mental processes such as thinking, perceiving, deciding, and using memory - domain of psychology and behavior (mental) Neuroscience: study of the nervous system - domain of biology and chemistry (physical) 1. Neuron structure and function - electrical ( w/n) vs chemical (b/w) Structure of the Brain: A. Neuron ● Dendrite: branching structures that receive input from other neurons ● Cell body (soma): nucleus, genetic material ● Axon: transmits action potential, produces output to other neurons ○ Myelin sheath: fatty insulation that speeds signal transfer B. Terms for Orientation/Navigation 1. Neural Processing and Communication ● Action potential: electrical signal that propagates down the axon to release neurotransmitters (chemical) ● Synapse: gap between neurons (where axon meets dendrite) ● Neural integration: when transmitters bind to receptors it can change the electrical polarity (charge) of the soma ○ if enough depolarization occurs, an action potent is generated in the next neuron 2. Neural communication and coding ● Communication through neurons: ○ Input: Receive neurotransmitters from other neurons through dendrites ○ Calculation: add inputs from all dendrites ■ if sufficient amount of depolarization, generate action potential ○ Output: Propagate electrical signal down the axon ■ release neurotransmitters across synapse ● Coding information: carried through the rate and/or timing of neural spikes ○ the action potentials are the spikes, represent the ratehow quickly they fire, or the timing how quickly they actually occur Anatomy of the Brain*** “City Analogy” 1. Outside layer→ “Buildings and offices” ● Grey matter: Location of neural processing. ○ Where input becomes ○ representation ( light → abstract) ● Cortical surface- ○ contains cell bodies (soma): integrate info from other neurons 2. Inner layer → “Roads and plumbing” ● White matter: Involved in transmitting information ● Subsurface: Contains ○ myelinated axons 2. Brain structure ● Lobes, directions, regions Navigating the Brain “language to show orientation” Lateral ← → vs. Medial → ← Sagital Cornal Horizontal Anatomy Terms: ● Cortex-wrinkly 1. Gyrus- “mountains” 2. Sulcus- “valleys” ○ raised surface dips or folds 4 lobes: ● anatomical reasons central sulcus separates frontal from parietal ○ junctions are where lobes meet ● Functions: ○ temporal learning, object perception ○ frontal executive control ○ occipitalvision ○ parietalprocessing sensory information regarding the location of parts of the body as well as interpreting visual information and processing language and mathematics ● inferior temporal gyrus: involved in representation of objects, independent of view, lighting etc Cerebral Cortex: ● if we know the direction and lobe we can identify the GYRI! → corpus callosum connects the two hemispheres white area 3. Brain Function ● Role of main structures Subcortex: Basal Ganglia ● Basal Ganglia: regulating motor activity and starting/stopping action (purple area)--> involved in Parkinson’s Disease- lack of DA causes tremors ***** ot in Basal Gangli Subcortex: Limbic System Involved in memory and emotional processing ● Amygdala: processing emotion and threat & negative emotions- fight or flight response → phobias ○ adrenaline ● Cingulate gyrus: detecting “conflict” ○ decision making ● Hippocampus: binding items and events in memory ● “remember name and face” ● Olfactory bulb: processing smell ○ right above the nasal cavity ○ sent tied w/ emotions Subcortex: Thalamic Bodies Involved in sensory processing and regulating bodily processes ● Thalamus: sensory relay for all senses except smell ○ “Central Station” ● Hypothalamus: body regulation (homeostasis) ○ releases hormones affecting hunger, breathing, temp etc Midbrain: ● The midbrain is OLD in evoluterms. Provides a fast (unprocessedroute for sensory information ○ e.g., attention grabbing flash or bang -animal instinct ● Superior Colliculi: integrate information from most of our senses- vision, heaand touch ● Inferior Colliculi: speciauditory processing only Hindbrain: ● Cerebellum: needed for movement coordination and motor control ○ Integrates motor plans with sensory information about the external world ● Pons: link between Cerebrum and Cerebellum (see above) ● Medulla (oblongata): connpons and spinal cord. ○ Crucial regulating breathing, heart rate, etc. Electrophysiology: → Recording electrical signals from the brain 1) Single cell recordings- probe to show one neuron’s functioning 2) EEG and broad recordings- cap on skull to see where electrical signals are coming from within the brain Relate to cognitive process 1) record response times in different conditions Neural coding of information: 2 Types 1. Rate coding: the number/rate of spikes reflects the coded information (not the size of spike) → Neuron that codes for “blue”: the size is the same, but different rates light blue medium blue dark blue 2. Temporal coding: the timing/coherence of spikes reflects the coded information Distributed vs Sparse Coding ● Sparse Coding: one neuron fires in response to “blue” ○ only one blue neuron expressed ○ “grandmother cell” ○ if the blue neuron dies you can never represent blue ● Sparse Distributed: a smaller pattern of neurons in response to the blue ○ blue pattern ( in colored region) ○ can still represent b/c only one neuron dies ● Fully distributed coding: all neurons in a region fire in response to “blue” ○ entire region blue ○ can still represent b/c only death to one neuron → Distributed Representation: ● most robust to cell death Representing complex information ● Different features of item are distributed across different systems, and at different levels → Representation of a blue heart ● Early visual neurons: pattern of activation to reflect ○ “curved lines” ○ “top-middle of screen” ○ “light blue” ○ “not moving” ● Higher level visual/object neurons: pattern to reflect ○ “closed blue object” ● Higher level semantic/emotional/memorial neurons: pattern to reflect ○ “blue heart” ○ “love” Neural firing and coding for information ● So we know that neurons “code” for information with their spikes ■ either the number (rate) or timing (temporal) of the spikes ● And we know that these spikes are electrical ● So one way to find out what the brain is doing is to try and record the electrical ○ signals it produces ○ starts at low level of processing ○ goes to higher level How do we explore these representations? 1. Single Cell Recordings: Basic procedure: insert probe into brain and locate cell ● Very direct way to record neural activity ● Do some physical or psychological task (show a ● invasive methodology verticalline) - can do research on ● See if firing rate changes as a function of the patients if they are already stimulus doing a surgery that is invasive Procedure INVASIVE [literally stick a probe into the brain] can now be ○ Typically done in animals (e.g. primates, extended rodents) to multiple ● But can be done on humans, for example cell recordings when they are undergoing brain surgery -array of many electrodes inserted to record from multiple neurons at once 2. Electroencephalography (EEG) If representations are distributed across space, then recording from a single neuron might not give us much information (lose the forest for the trees) EEG: Based on electrical signal from postsynaptic currents recorded from scalp NON INVASIVE, whole brain coverage → Instead of counting spike rate, measures overall electrical signal → Does the charge become more positive or negative at different times/locations? EEG signal is affected by a lot of different things, not just the experiment -- eye blinks, spikes from other neurons that aren’t task related ● Consequently, the signal-to-noise ratio is very low - hard to find an effect from just one trial 3. Event Related Potential (ERP) So we run the same type of trial repeatedly - and then average the EEG signal (potential) tharelatedto that stimulusor “event” → ERP: repeat trials to get a better signal-noise ratio “Endogeneous vs Exogeneous” 1. Exogenous components: due to external factors (e.g., the stimulus on the screen) ● Generally affect early ERP components (the input) 2. Endogenous components: due to internal factors, like how you process that stimulus ● generally affect late ERP components (the processing and output) Pros and Cons of EEG Pros: Cons: ● noninvasive ● only works for cortex (no signal from ● relatively cheap subcortical regions) ● great temporal resolution *** ● awful spatial resolution *** ● can detect distinct events at the ● Can’t really tell where the signal millisecond level originated in the brain ● EEG is really good at telling us WHEN ● really bad at telling us WHERE in the the brain was active brain the activity occurs Pros and Cons of Single/Multi Cell Recording Pros: Cons: ● Very direct measurement of neuronal ○ Invasive, Invasive, Invasive activity ○ Only information about a specific ● Very good temporal and spatial area (no whole brain coverage) resolution ● always know when and where it’s happening 4. Mental Chronometry So we can record brain signals from single neurons, or from the whole scalp, but how do we relate these to psychological processes? → Timing is everything ● A big chunk of psychological research is concerned with response/reaction times ● harder or more complex tasks take longer to do ● Read about additive factors method and stages of processing: - ex. Sternberg and Donder’s work - Increasing the complexity of one of these stages leads to an increase in response times encoding → comparison → decision → response Pro Con MRI → record magnetic field - great spatial - expensive produced by issue/bood, resolution - availability send ratio pulse to disturb - safe, noninvasive - metal field and see how long it - can distinguish diff. - claustrophobia takes to return to normal type of tissue - expensive - detects changes in blood flow TMS → “virtual lesion” turn - clear and not messy - can cause discomfort parts of brain off and they (focal lesion) - small area (no brain will eventually come back on! - precise timing coverage) - can check diff. areas in same area Functional MRI: fMRI → The brain needs blood to deliver oxygen (and glucose) ○ When part of the brain is active and uses oxygen, ■ bloodflow increases to that region to replenish the fuel ■ fMRI is sensitive to the amount of oxygen in the blood ● BOLD signal: blood oxygen level dependent signal-amount in blood that triggers signal ● Indirect measure of neural activity -E.g., You want to know how hard different players work in a practice 1. Indirect vs Direct ● Direct measure (EEG): measure amount of sweat or heart rate ● Indirect (fMRI): measure how much Gatorade they drank after 2. fMRI (BOLD) contrast ● The brain is always active, and always using oxygen (neurons are always firing!!!) -So looking for where oxygen is being consumed is futile Answer = “everywhere” 3. Subtraction Approach ● Instead we use a baseline condition to contrast with ○ use a baseline (constant measurement) to compare the changes in activity ***keep comparison consistent ● commonly used in cog. psychology ● Reading a word vs deciding if you remember the word → ex. is the hippocampus activation -----Where in the brain do we see greater BOLD for memory? Limitations to the Subtraction Approach → 2 conditions might differ in more than one way Pure insertion:adding the memory component could affect the other components ● does NOT take account for 3rd variable effects -Maybe the memory component is hard, so it also leads to greater effort. - Carryover Effects ● refined baseline: be as similar as possible and eliminate other variables ● make as similar as possible & be SPECIFIC 4. Parametric design: ● Look for BOLD signal that shows a relationship with each cognitive construct ● Observe relationship between BOLD activity and cognitive constructs 1) Change the size/number of the dots on each trial ● Para = across a range ● Metric = a value for something we can measure (e.g., number of dots) 2) Look for regions in the brain where the BOLD activity tracks the value of that metric Neuroimaging and brain mapping:2 Types 1. Structural Imagingbased on the fact that different types of t have different magnetic properties ● Static high resolution mapdetect tumor or fracture in bone 2.Functional imaging:changes in neural activity in response to a task ● Dynamic map: detect changes in oxygenated blood flow -when certain parts of the brain are being activated -6 min. “video” snap-shots of what is moving Activation vs Integration: the WHERE! Activationdoes this region show more BOLD in one condition? Integratio: does activation in one region relate to activation in another? ● they are in a network- work together (do the same thing/ regions up or down regulate at the same time) ● Functional connectivityDoes a change in X lead to a change in Y? ○ Are these regions talking to each other? yes, but can NOT identify direction/relationship: which is the response or stimulus→ can’t determine CAUSALITY -Temporal Patients vs Animals Types of Patient Study 1. Group study → E.g., compare 20 Parkinson’s patient with 20 matched controls ---Very important to match participants on every factor you can 2. Case study: → Focus on one individual with damage ○fractionation: damage affects only one system ○transparency: brain does not compensate for damage ○universality: our brains are similar enough that the same would happen to me Transcranial Magnetic Stimulation (TMS) ● Induce focused magnetic energy current in neurons to deactivate brain region - Induce temporary lesion NOT permanent → focused magnetic pulse fired through head to turn on and off neurons “make them fire” ● can simulate brain damage effects on a normal functioning patient ● small area (~ 1 cm) → repetitive stimulation disrupts their regular function Control conditio****will be on test → will show WHERE & WHEN Yes: pulse at different times, different locations, different task No: sham pulse (aimed away from head) ex. from picture→ stimulated the inferior frontal Gyrus → put magnet on motor cortex→ put on part of brain that will allow thumb to twitch → can’t do permanent damage b/c Ethical purposes Advantages: ● No time for brain reorganization (transparency assumption) ○ pulse goes into brain- cortex outer layer stimulation, not inner brain or basal ganglia ( 1-3 cm deep) ● Precise timing ○ early or late in the decision ● Focal lesion (not messy like real lesion) ○ target specific region of brain → relates to real problems ● Can check different areas in samerson Weird Situation: → “turn off” neural system, and performance improves → Could mean that the system competes with system needed for performance Animal Model → Create cognitive task for rodents or primates (solve maze) ● lesion part of the brain to assess its effects ● can cause permanent damage, however ethical issues → used in Behavioral neuroscience ● Train animal to perform some task ● meant to mimic a cognitive process (remember a maze route) Limitations to Animal Models: ● Brains might not be just a “weaker version” of ours ● Less of a problem with primates than it is with rodents ● Can’t have animal do complex task → Ethics and safety ● Is this acceptable? ● PETA break ins Dissociating Impairments ● What can patient populations do? What can’t they do? ● Compare Patients to Controls ○ Patients CAN make simple decisions ○ But CAN NOT make memory decisions → Conclusion: lesioned region in responsible for memory processing ● Sometimes it is useful to look at behavior from people who have damage 1. Pre-existing damage: Case or group studies many limitations 2. Induced damage: animal models or TMS any limitations
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