AP Psychology - 1.4

Neuroplasticity

the brain’s ability to change, build, and reorganize after damage or experience; easier for kids than adults

Neurogenesis

the process of forming new neurons

Lesioning

the removal or destruction of part of the brain (usually for behavior modification or medical treatment, not experiments)

How does lesioning help scientists learn about the brain?

Any time brain tissue is removed, researchers can examine behavior changes and try to infer the function of that part of the brain

Techniques for Researching the Brain

• Electroencephalogram (EEG)

• Magnetoencephalogram (MEG)

• Computed Tomography (CT)/Computerized Axial Tomography (CAT)

• Positron Emission Tomography (PET)

• Magnetic Resonance Imaging (MRI)

• Functional Magnetic Resonance Imaging (fMRI)

Electroencephalogram (EEG)

detects brain waves by placing electrodes on the scalp to measure electrical activity in neurons

Example of how an EEG is used

Researchers can examine what type of waves the brain produces during different stages of consciousness and use this information to generalize about brain function.

CAT/CT

X-ray cameras rotate around the brain and combine all the pictures into a detailed three-dimensional picture of the brain’s structure. Only shows the structure of the brain, not the function

Example of CT/CAT usage

help look for tumors in the brain or brain damage, which helps predict impairments in intelligence and memory processing

→ you wouldn’t get information about how active different parts of the brain are

PET

tracks where a temporarily radioactive form of a chemical (e.g., glucose) goes while the brain of the person given it performs a given task and measures how much of it parts of the brain are using. helps researchers identify which areas of the brain are most active during certain tasks

MRI

uses magnetic fields and radio waves to measure the density and location of brain material, providing a map of brain structure. doesn’t give information on the function of the brain

fMRI

measures blood flow to brain regions by comparing continuous MRI scans, tying brain structure to brain activity during cognitive tasks

Major categories or section of brain when studying neuroanatomy (from oldest to newest)

1. Hindbrain

2. Midbrain

3. Forebrain

Hindbrain

• located on top of the spinal cord

• body’s life support system

• controls basic biological functions that keep us alive

What structures are part of the hindbrain?

• pons

• medulla

• cerebellum

What is the oldest part of the brain

Brain stem

Brain stem

• found at the base of the skull above the spinal cord

• responsible for automatic survival functions

• includes: pons, medulla, and midbrain

Medulla

• base of the brainstem, above spinal cord

• controls bp, heart rate, and breathing

What would happen if the medulla was damaged?

die or be on life support

Pons

• located on the bottom rear of the brain

• connects hindbrain with midbrain and forebrain

• controls facial expressions, REM sleep, and breathing

• connects cerebrum to cerebellum, allowing for coordinated motor control

Cerebellum

• located on the bottom rear of the brain

• coordinates voluntary movement and balance

• processes sensory input & judgment of time

• enables nonverbal learning and memory

• coordinates some habitual muscle movements, such as tracking a target with our eyes or moving fingers when playing an instrument

Why do people stagger and struggle to react quickly when drunk?

Because the cerebellum is one of the first parts of the brain impacted by alcohol

Midbrain

• integrates some types of sensory information and muscle movements (coordinates simple movements with sensory information)

• connects hindbrain to forebrain

While reading a text, Alicia moves her head sideways yet is still able to read. How is that possible?

Her midbrain coordinates with muscle movements in her eyes to keep them focused on the text.

Reticular formation

• a nerve network that travels through the brainstem

• controls general body arousal and the ability to focus our attention

What would happen if the reticular formation was damaged?

be in a state of permanent sleep (coma) or wakefulness

Forebrain

• largest and most complex brain section

• involved in:

  • memory

  • emotion

  • reasoning

  • personality

  • communication

  • complex thought

  • other cognitive functions

Parts of the forebrain

• thalamus

• hypothalamus

• hippocampus

• amygdala

• cerebrum

Thalamus

• located at the top of the brainstem

• directs messages from spinal cord to sensory-receiving areas in the cortex and transmits replies to the cerebellum and medulla

What kinds of sensory information does the thalamus receive?

sensory information from all senses EXCEPT smell

Limbic System

• neural system located below the cerebral hemispheres

• associated with emotions, drives, and memory
  

What parts of the brain are part of the limbic system?

• amygdala

• hippocampus

• hypothalamus

Amygdala

• structures near the end of each hippocampal arm

• vital to our experiences of emotion

• responsible for survival emotions of fear and aggression

Hippocampus

• two armlike structures surrounding the thalamus

• responsible for:

  • processing memories

  • converting short-term to long-term memory

  • temporarily storing explicit memories

  • forming explicit memories

Hypothalamus

• below the thalamus

• controls several metabolic functions & maintenance behaviors such as:

  • eating

  • drinking

  • maintaining optimal body temp.

  • the endocrine system (via the pituitary gland)

  • sexual arousal (libido)

  • biological rhythms

• linked to emotion and reward

Pituitary Gland

• controlled by the hypothalamus

• responsible for the release of hormones throughout the body by controlling all endocrine glands

Pineal Gland

produces melatonin, regulating the body’s sleep cycle

Cerebral Cortex

• the outer layer of the brain that is made of densely packed, interconnected neurons covering the cerebral hemispheres

• body’s ultimate control and information-processing center

• plays a key role in:

  • memory

  • attention

  • perceptual awareness

  • thinking

  • speaking

  • consciousness

• organized into lobes based on functions

What are the four lobes of the cerebral cortex?

• frontal

• parietal

• temporal

• occipital

How does the cerebral cortex change as we learn and develop?

When we are born, our cerebral cortex is full of neurons that are not yet well-connected. As we develop and learn, the dendrites of the neurons grow and connect with other neurons

Fissures

the wrinkles of the cerebral cortex that increase the surface area of the brain

Frontal Lobe

• largest lobe

• located at the top front part of the brain behind the eyes

Prefrontal Cortex

• anterior or front of the frontal lobe

• the brain’s central executive (responsible for high-order cognitive processes)

• responsible for:

  • directing thought processes

  • predicting consequences

  • pursuing goals

  • maintaining emotional control

  • abstract thought

  • making judgements

  • planning & decision-making

  • personality

Broca’s Area

• found in left hemisphere of frontal lobe

• controls muscles that produce speech

Broca’s Aphasia

a condition resulting from damage to Broca’s area characterized by difficulty in producing language, but relatively preserved comprehension

Motor Cortex

• thin vertical strip at the back of the frontal lobe (farthest from the eyes)

• sends signals to our muscles, controlling voluntary muscle movements

• the top of the body is controlled by the neurons at the bottom of this cortex (by the ears), progressing down the body as you go up the cortex (so, top of the motor cortex controls feet and toes of the body)

Parietal Lobe

• located behind the frontal lobe but still on the top of the brain

• receives sensory input for touch sensations (pain, pressure, & temperature) and body position

• contains somatosensory cortex

Angular Gyrus

region in the parietal lobe responsible for:

• written language

• number processing

• spatial recognition

• elements of memory

Somatosensory Cortex

• located right behind the motor cortex

• thin vertical strip that receives incoming touch sensations from the rest of the body

• the top of the sensory cortex receives sensations from the bottom of the body, progressing down the cortex to the bottom, which processes signals from our face and head

Occipital Lobe

• at the very back of the brain, farthest from the eyes, above the cerebellum

• receives and interprets messages from our eyes in our visual cortex

  • Light entering the left half of each eye's retina (which receives light from the right visual field) travels to the left side of the brain.

  • Light entering the right half of each eye's retina (which receives light from the left visual field) travels to the right side of the brain

Temporal Lobe

• above the ears

• receives, processes, and interprets sound sensed by our ears in the auditory cortices

  • auditory cortices receive auditory signals from both ears, but primarily process information from the opposite ear

• contains Wernicke’s Area

Wernicke’s Area

region in the temporal lobe that is responsible for linguistic processing via both written and spoken speech

Wernicke’s Aphasia

a condition resulting from damage to Wernicke’s area characterized by difficulty in understanding language and in using grammar and syntax correctly for meaningful communication

Why would hitting someone at the back of the head make them “see stars” or temporarily blur their vision?

Because the occipital lobe is located there

Case Study: Phineas Gage

• In the mid-1800s, the railway worker Phineas Gage survived a major brain injury that damaged the front part of his brain.

• It caused several changes to his personality, behavior, and performance. For example, he became highly emotional and impulsive.

• This confirmed that different brain regions are responsible for different functions and that the parts of the brain damaged in the accident are involved in emotional control

Association Areas

• any area of the cerebral cortex not associated with receiving sensory information or controlling muscle movements

• involved in higher-mental functions, such as:

  • judgment

  • humor

  • learning

  • remembering

  • abstract thinking

  • language & speaking

• enable us to:

  • produce a meaningful perceptual experience of the world

  • interact effectively

Corpus Callosum

bundle of nerve fibers that connects the two hemispheres, allowing communication between them

Split-Brain Procedure

• a treatment done to patients with severe epileptic seizures, in which their corpus callosum was cut/severed

• it eliminated their seizures but caused some difficulty in basic tasks as the two hemispheres couldn’t communicate with each other

Example of Split-Brain Side Effects

• A word is flashed to the right visual field of a person, which is transmitted to the left hemisphere. When asked what they saw, the person is able to say the word they saw out loud (since the spoken language centers of the brain are usually located in the left hemisphere)

• The same word is flashed to the left visual field of a person, which is transmitted to the right hemisphere. When asked about what they saw, the person was unable to SAY the word because the right hemisphere couldn’t communicate with the left hemisphere (aka, the language center didn’t receive any orders to verbally say the word) but he was able to draw it

Brain Laterization/Hemispheric Organization

• the tendency for some neural functions or cognitive processes to be specialized to one side of the brain or the other.

• for example, the left hemisphere may be more active during logic and sequential tasks while the right hemisphere may be more active during spatial and creative tasks

Contralateral Hemispheric Organization

the idea that each side of the brain controls the opposite side of the body

Consciousness

subjective awareness of ourselves and our environment that helps us cope with new situations, read amotions of others, and follow through on long-term goals

Cognitive Neuroscience

the study of the brain activity linked with cognition, including language, perception, memory, and thinking

Levels of Consciousness

1. Conscious level

2. Nonconscious level

3. Preconscious level

4. Subconscious level

5. Unconscious level

Conscious Level

the information about yourself and your environment you are currently aware of

Nonconscious Level

bodily processes controlled by your mind that we are not usually (or ever) aware of

Preconscious Level

information about yourself or your environment that you are not currently thinking about but could be.

→ for example, if I asked you to remember your favorite toy as a child, you could bring that preconscious memory to your conscious level.

Subconscious Level

information that we are not consciously aware of, but we know must exist due to behavior

→ for example, behaviors demonstrated in the mere-exposure effect suggest that some information is accessible to our subconscious level but not our conscious level

Unconscious Level

some events and feelings are unacceptable to our conscious mind and are repressed into the unconscious mind

Dual Processing

the concept that the brain processes information consciously and coconsciously

→ example: when seeing a bird, you’ll be consciously aware of which type of bird it is but unconsciously be taking in information about its color, size, movement, etc.

Parallel Processing

the ability to simultaneously process multiple pieces of information or stimuli at the same time

Sequential Processing

the processing of one aspect of a problem at a time; it is used for processing new information or solving difficult problems

Blindsight

the ability to respond to visual information without consciously seeing it; it explains how blind people can sense objects in their environment

Circadian Rhythm

our biological clock that regulates our mood, temperature, and arousal through a 24-hour cycle

Describe the changes the circadian rhythm causes to our body during a 24-hour period

As morning approaches, our body temperatures rise and we begin to wake up. Our temperature and arousal peak around midday, then start to dip as we approach dusk

Why do most people prefer to sleep in colder temperatures?

Because our circadian rhythm causes our temperatures to decrease at night, colder temperatures help with that process, signaling it’s time to sleep and thus promoting faster and deeper sleep.

Other Biological Rhythms

• 90-minute sleep cycle

• 28-day menstrual cycle

• annual hibernation/migration

• mating seasons

Stages of Sleep

1. NREM Stage 1 (NREM-1)

2. NREM Stage 2 (NREM-2)

3. NREM Stage 3 (NREM-3)

4. NREM-2

5. REM

Sleep Onset

• process of transitioning from wakefulness into sleep

• a person might experience mild hallucinations during this stage

• hypnagogic sensations can be experienced in late sleep onset

NREM-1

• light sleep, easily woken

• EEG shows theta waves with high-frequency and low-amplitude

• can experience hallucinations and hypnagogic sensations

Hypnagogic Sensations

bizarre experiences such as jerking with a sensation of falling

NREM-2

• fully asleep, but still light sleep (but deeper than NREM-1)

• EEG shows theta waves with sleep spindles and K-complexes

• theta waves are a bit slower (low frequency) and higher in amplitude compared to NREM-1

Sleep Spindles

random short bursts of rapid brain waves

K-complexes

random tall bursts of activity

NREM-3

• deep sleep

• also called delta sleep (or deep or slow-wave sleep)

• EEG shows delta waves (lowest frequency and highest amplitude)

• a person in NREM-3 is hard to wake up and is very disoriented and groggy if awakened

• slower wave (lower frequency) → deeper sleep → less aware a person is of environment

Purpose of NREM-3

very important in:

• releasing growth hormones in children

• fortifying immunity

• restoration of resources used while we are awake and active

How does increasing exercise affect our sleep and why?

Increasing exercise will increase the amount of time we spend in NREM sleep in order to replenish the resources used.

Predict what would happen to a person deprived of delta sleep

they would be more susceptible to illness and will feel physically tired

REM

• also known as paradoxical sleep since brain waves appear as active and intense as they do when we are awake

• a period of intense activity, in which eyes dart back and forth and many of our muscles may twitch repeatedly

• dreams (especially vivid dreams) are more likely to occur in this sleep stage

• becomes longer & more frequent as night progresses

• EEG shows beta waves

What affects how much time a person spends in REM sleep?

• Age: as we age, the amount of time spent in REM sleep decreases

• Stress: more stress → longer periods of REM sleep

• REM Deprivation: leads to REM Rebound

REM Rebound

the tendency for REM sleep-deprived individuals to experience more and longer periods of REM sleep the next time they are allowed to sleep normally

What affects our sleeping?

• Age: as we age, our total need for sleep decreases

• Genetics

• Environment

• Exposure to light

• Brain:

  • Pineal gland: adjust melatonin levels

  • Reticular Formation: monitors sleep and wake cycle

  • Suprachiasmatic Nucleus (SCN)

Suprachiasmatic Nucleus

a pair of cell clusters in the hypothalamus that control circadian rhythm

What happens to our sleep as we get closer to morning (or whenever we naturally wake up)?

we spend more time in NREM stages 1 and 2 and in REM sleep and less in NREM stage 3

Insomnia

persistent problems falling or staying asleep

Insomnia Treatment

• reducing intake of caffeine or other stimulants

• exercising at appropriate times (not before bedtime) during the day