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SYRACUSE / Psychology / PSY 223 / What are the four lobes of the brain?

What are the four lobes of the brain?

What are the four lobes of the brain?

Description

School: Syracuse University
Department: Psychology
Course: Intro to Cognitive Neuroscience
Professor: C. white
Term: Summer 2015
Tags:
Cost: 50
Name: PSY 223: Exam 1 Study Guide
Description: All material covered for exam 1. This includes key topics, terms, and definitions, as well as all lecture notes up til the exam.
Uploaded: 11/02/2015
13 Pages 61 Views 2 Unlocks
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Topics 


What are the four lobes of the brain?



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 


What are the pros and cons of electroencephalography (eeg)?



● Dendrite: branching structures that receive input from other neurons ● Cell body (soma): nucleus, genetic material We also discuss several other topics like Why do we feel anger? guilt?
Don't forget about the age old question of What are the sex-linked disorders?

● Axon: transmits action potential, produces output to other neurons ○ Myelin sheath: fatty insulation that speeds signal transferWe also discuss several other topics like What is the difference between pop control and fertility control?

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


What is the branching structures that receive input from other neurons?



If you want to learn more check out Why technological process is a source of sustained growth in gdp?

○ if enough depolarization occurs, an action potential 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 If you want to learn more check out Why technological change is more than a constant increase, such as 10 more units. rather, it is exponential in that the rate of increase is approximately constant, such as 10%?

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*** Don't forget about the age old question of In what year did frederick griffith discover the "transformation factor"?

“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

***** not 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 evolutionary terms. Provides a fast

(unprocessed) route for sensory information

○ e.g., attention grabbing flash or bang -animal

instinct

● Superior Colliculi: integrate information from most of our

senses- vision, hearing, and touch

● Inferior Colliculi: specialized for auditory 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): connects pons and spinal cord.

○ Crucial for 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

Distributed vs Sparse Coding 

of spikes reflects the coded information

● 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: 

● Very direct way to record

neural activity

● invasive methodology

- can do research on

patients if they are already

doing a surgery that is invasive

INVASIVE [literally stick a probe into the brain] ○ Typically done in animals (e.g. primates, rodents)

● But can be done on humans, for example when they are undergoing brain surgery

Basic procedure: insert probe into brain and locate cell

● Do some physical or psychological task (show a verticalline)

● See if firing rate changes as a function of the stimulus

Procedure

can now be

extended

to multiple

cell recordings

-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) that is related to

that stimulus or “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:

● noninvasive

● relatively cheap

● great temporal resolution ***

● can detect distinct events at the

millisecond level

● EEG is really good at telling us WHEN the brain was active

Cons:

● only works for cortex (no signal from subcortical regions)

● awful spatial resolution ***

● Can’t really tell where the signal

originated in the brain

● really bad at telling us WHERE in the brain the activity occurs

Pros and Cons of Single/Multi Cell Recording 

Pros:

● Very direct measurement of neuronal activity

● Very good temporal and spatial

resolution

● always know when and where it’s

happening

Cons:

○ Invasive, Invasive, Invasive

○ Only information about a specific area (no whole brain coverage)

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 produced by issue/bood, send ratio pulse to disturb field and see how long it takes to return to normal

- great spatial

resolution

- safe, noninvasive

- can distinguish diff.

type of tissue

- detects changes in

blood flow

- expensive

- availability

- metal

- claustrophobia

- expensive

TMS → “virtual lesion” turn parts of brain off and they will eventually come back on!

- clear and not messy

(focal lesion)

- precise timing

- can check diff. areas in same area

- can cause discomfort - small area (no brain

coverage)

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 Imaging: based on the fact that different types of tissue have different magnetic properties

● Static high resolution map:​detect 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! 

Activation: does this region show more BOLD in one condition?

Integration: 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 connectivity: Does 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 condition: ****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 same person

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 many limitations

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