Brain and Behavior: Biological Psychology

Studying the Brain and Behavior

• Biological psychologists/neuroscientists study the brain and its relationship to behavior
• The brain consists of ~1.4kg of protein, fat, and fluid
• The brain contains ~100 billion neurons (nerve cells) communicating in a complex system
• Synaptic pruning occurs in early years, eliminating unused neurons

Old Methods in Biological Psychology

• Phrenology explored size and protrusions of the cranium
• Franz Gall (1758-1828) is considered the "father" of phrenology
• Phrenology wrongly assumed the brain was the sole organ of the mind, character and intelligence are inherited, and structural brain differences cause differences between people
• Though misguided, phrenology was a precursor to neuroscience

Electrical Stimulation Studies

• Neurosurgery patients were electrically stimulated to investigate brain function
• This technique helped prove neural communication is electrical
• Wilder Penfield developed and expanded electrical stimulation, creating the "Penfield map" of motor and sensory cortex

Deep Brain Stimulation (DBS)

• Deep Brain Stimulation (DBS) involves implanting battery-powered electrodes to electrically stimulate specific brain areas
• DBS treats neuropsychological conditions and assess brain activity
• DBS is invasive, carrying risks such as infection, hemorrhage, and requiring battery replacement
• Researchers lack control over electrode placement and implantation is necessary for medical reasons

Electrical Recording: EEG

• Electroencephalography (EEG) records the brain’s electrical activity from the skull's surface
• EEG is non-invasive with relatively low cost and high temporal resolution
• EEG disadvantages include not revealing individual cell activity and low spatial resolution
• Event Related Potential (ERP) studies use EEG data, usually through case studies or group studies

Lesion Studies

• Lesion studies assess psychological functioning by studying individuals with brain lesions and deficits
• In animal models, lesions clarify the function of specific brain areas

Structural Imaging

• Computed Tomography (CT) uses multiple X-rays for a 3D brain reconstruction
• CT advantage: good for detecting lesions and skull fractures, inexpensive
• CT disadvantages: images in one direction, lower resolution, doesn't show brain activity over time, exposes patient to low-dose radiation
• Structural MRI uses powerful magnetic fields to create high-resolution brain images
• MRI advantage: better for detecting soft tissue and higher spatial resolution than CT scans
• MRI disadvantages: more expensive, cannot have metal in body, risk of motion artifacts and claustrophobia

Functional Imaging

• Functional Imaging using PET scans employs trace amounts of short-lived radioactively labeled oxygen or glucose to map functional processes
• PET advantage: Enable radioactive isotopes to attach to drugs to see where they are used
• PET disadvantage: invasive with poor temporal resolution (30-60 sec)

Functional Imaging: fMRI

• Functional Magnetic Resonance Imaging (fMRI) detects blood oxygenation changes related to neural activity
• Commonly used for brain-imaging research
• fMRI advantage: Excellent spatial resolution
• fMRI disadvantages: Poor temporal resolution (better than PET), same restrictions as structural MRI

Functional Imaging: MEG

• Magnetoencephalography (MEG) measures brain activity by detecting tiny magnetic fields from electrical signals
• MEG advantages: Excellent temporal resolution and reasonable spatial resolution
• MEG disadvantages: not ideal for detecting activity deep in the brain, expensive

Transcranial Magnetic Stimulation (TMS)

• Transcranial Magnetic Stimulation (TMS) applies magnetic fields to the skull's surface to enhance or interrupt brain function
• TMS advantage: can influence neural function transiently (causality), good temporal resolution
• TMS Disadvantages: limited to outer brain layers (cortex), may cause seizures if not careful

Localization of Function

• Localization of function means specific brain areas are particularly active while doing specific psychological tasks
• These claims require strong evidence and caution
• Most brain areas work together uniquely depending on the task
• Broca's area is an example, helping with speech comprehension

Neural Communication

• Neuron components: cell body (soma), dendrites, axon, axon terminals (buttons), synapse
• Electrical signals send information within a cell, but chemicals send signals between cells
• Chemical information is transferred in the synapse
• Glial cells: support for neurons and neuronal functioning via regulating environment, form blood-brain barrier and synapses, and are involved in multiple sclerosis (MS)

Action Potential Terms

• Action potentials are electrical signals that enable neuron communication
• Resting potential equals -70
• Action potential (AP) is when a neuron fires
• Threshold equals -55
• Absolute refractory period is 1-2ms during AP initiation when another AP is impossible
• Relative refractory period: 2-4ms after AP, requires more stimulation for another AP
• All or none law: action potential either fires or not
• Stronger signals don't cause stronger action potentials
• Rate law: stronger signals lead to more action potentials and a higher firing rate

Chemical Communication

• Chemical communication occurs between neurons using neurotransmitters released from the presynaptic neuron
• Excitatory neurotransmitters create positive stimulation that excites neurons
• Inhibitory neurotransmitters add negative stimulation that blocks cell function
• Neurotransmitters bind on postsynaptic neuron dendrites and deactivate through reuptake

Neurotransmitters and their Functions

• Glutamate: main excitatory NT, involved in sensory processes and learning
• GABA: main inhibitory NT helps anti-anxiety
• Norepinephrine: crucial for cortical arousal
• Acetylcholine: involves arousal, selective attention, memory, muscle contraction
• Dopamine: motor function, reward via L-dopa for Parkinson's, antipsychotics
• Serotonin: mood regulation, aggression, sleep-wake cycle, temperature via antidepressants
• Endorphins: pain killers
• Anandamide: also pain killers and increases appetite
• Psychoactive drugs impact nervous system via agonists and antagonists

Psychoactive Drug Functions

• Agonist: drug that enhances activity at the receptor site by binding to the site or blocking reuptake
• Antagonist: drug that decreases activity at the receptor site and blocks neurotransmitters

Neural Plasticity and its Aspects

• Neural plasticity means neurons can change over time
• Plasticity over development: neuron networks change via growth, synaptogenesis, pruning, myelination during development
• Plasticity and learning: brains undergo change when learning
• New synapses creation (synaptogenesis) with Hebb's rule: neurons that fire together, wire together
• Structural plasticity refers to neuron structure changes

Plasticity Following Injury

• Brain regeneration is limited after serious damage
• Neural connections or brain regions can compensate damage
• Sometimes the brain can repair damage via neurogenesis
• Stem cells can differentiate into nearly any cell type in the body
• Implanted stem cells in nervous system may differentiate and repair damage

Central Nervous System: Cortex

• Frontal lobe handles executive functions that coordinate other brain areas, motor planning, language, and decision making
• Parietal lobe processes touch information and integrates senses
• Temporal lobe handles auditory information, language, long-term memory
• Occipital lobe processes visual information

Central Nervous System: Basal Ganglia and Limbic System

• Basal ganglia control movement, motor planning, and skill/habit learning
• Thalamus conveys and integrates sensory information to the cortex
• Hypothalamus oversees hormone release and autonomic nervous system
• Amygdala modulates emotional learning/memory, including fear/aggression
• Hippocampus forms new long-term conscious memories, spatial navigation

Central Nervous System: Cerebellum, Brain Stem, Spinal Cord

• The cerebellum controls balance and precise movements
• The brainstem includes:
  • Midbrain which tracks visual stimuli and reflexes triggered by sound and regulates sleep, arousal, and motor movements
  • Pons coveys information between the cortex and cerebellum
  • Medulla regulates vital reflexes like breathing, sneezing, coughing
• The spinal cord conveys information between the brain and the rest of the body

Cerebral Cortex

• The cerebral cortex is the cerebrum's outermost part (or forebrain)
• The cerebral cortex helps sensory information be analyzed and perform functions, like reasoning/language
• Most developed part of the brain made of 2 cerebral hemispheres
• The cerebral hemispheres perform different functions (lateralization) and connected with corpus callosum (nerve fibers)
• The left hemisphere handles: speech comprehension/prosecution, phonology, syntax, reading/writing, facial expressions, motion detection
• The right hemisphere: simple speech/writing, tone of voice, perceptual grouping, face perception

Lobes of the Brain

• Motor cortex controls specific body parts and some parts require more control
• Prefrontal cortex controls thinking, planning, and language
• Broca's area allows speech
• Parietal lobe is the cerebrum's upper middle part as primary sensory cortex handling touch, pain, pressure, and temperature, and also helps navigate objects locations/ shapes/orientations
• Guides attention, processes actions and relays visual information to motor cortex also spatial perception

Temporal and Occipital Lobes

• Temporal lobe is for hearing, understanding language, and forming memories
• Contains auditory cortex and Wernicke's area (language area)
• Fusiform area (FFA) helps recognize faces
• Occipital lobe with just the visual cortex to see, and human dependance on visual system

Cortical Hierarchies

• Information comes in through sense, sent into thalamus then relayed to their primary sensory cortex of that sense
• Smell bypasses this as it heads straight to limbic system and olfactory cortex
• After going to sensory cortex the association cortex picks up information
• After the association cortex picks up information its passed along to the basal ganglia and a blueprint for action is created and sent tot he motor cortex

Pituitary Gland and Hormones

• The pituitary gland is a master gland that controls all other glands in the body as controlled by the hypothalamus
• Oxytocin: hormone for birth and milk flow, maternal and romantic love, and trust/syncronization
• Adrenal glands and adrenaline response to emergencies/threats
• Adrenaline boosts energy production, constricts blood vessels, opens bronchioles, breaks down fat and glycogen, and enables sight

Sensation versus Perception

• Sensation: physical energy detection by our sense organs, ex. incoming light and sound waves
• Perception: brain's interpretation of raw sensory inputs, ex. recognizing an object/voice
• Sensory transduction: translating all sensory stimuli into electrical signals by receptors
• Sensory adaptation: sensory systems focus on change via gradual sensitivity decline to prolonged stimulation

Psychophysics

• Psychophysics studies how we perceive sensory stimuli based on characteristics
• Gustav Fechner (1860) created psychophysics
• Absolute threshold: a stimulus's intensity that we detect in 50% of trials with no other stimuli
• Just Noticeable Difference: smallest intensity change we detect
• Ernst Weber developed Weber's law such as when the magnitude of stimulus increases, so does the JND

Signal Detection

• Signal detection describes how we detect stimuli under uncertain conditions
• Accounts for cognitive factors, like expectations/biases
• Standard signal detection experiment uses low-intensity stimulus presented on trials, or no stimulus at all
• Different categories of signal detection include; Hit: stimulus was present and detected, Miss: stimulus was present but undetected, False alarm: stimulus was absent but detected, and Correct rejection: stimulus was not present and not detected

Correct Rejection and Cross-modal Sensory Processing

• Correct rejection indicate there was stimulus, when there was no stimulus
• Cross-model: Are sensory systems independent?
• In 1826, Johannes Muller proposed the doctrine of specific nerve energies
  • States Our sensations are determined by the properties of sensory receptors (e.g. phosphenes)
  • There examples of cross-modal processing, some from many different senses that interact with one-another
  • The McGurk effect: a mismatch between what is seen and what is heard leads to inaccurate perception
  • Processing speech uses the brain to calculate probable sounds when information from vision/audition

1. How does this work?
2. Why is it important?
3. Your brain is gullible

Synesthesia

• Synesthesia: condition in which people feel cross-modal sensations/perceptions
• Over 60 types have identified to date
• Grapheme-color synesthesia: link between experiences and color with numbers/letters
• Mirror-touch: experience the feeling that other people feel (e.g touching)
• Lexical-gustatory: association with specific textures and tastes
• Chromesthesia: sounds trigger color
• Misophonia sounds trigger emotions(anger and fear)
• Personification, numbers, letters, days of the week take over personality features or characteristics
• Number-form: numbers imagined as mental maps
• Spatial sequence: number sequences, dates, and months perceived as closer or far away

Attention for Perception

• Attention depends on perception
• Our focus determines perception, excluding information
• Selective attention allows selection of sensory channel and ignoring information
• Reticular Activating System (RAS) and cerebral cortex are involved

Selective Attention

• selective attention: allows selection of sensory channel and ignoring information
  • Reticular activating system (RAS) in cerebral cortex are involved -Originally studied dichotic listening.
    • shadow required particpants to repeat audibly
    • intitial experienments showed people have inability to audibly repeat both ear pieces at the ame time
    • -Inatteional blindness- when focus is present some events of scene can go unnoticed if not actively thinking about doesnt capture conversation effect
  • Can perform multiple sensory modalities Bottom up processing, we contruct stimulus stimiulus Top down the effect that we feel due to experience or other factors

Parallel Processing

• Parallel processing the
• 2 impor concepts bottom up construct the while stimul Top down effect Perceptual effect we use to decider sensory input to see the world as is Gestalt principles: the Rules to follow 6 important rules following visual proximity

6 Main Principles

• 6main principles:
• Visual organization
• Proximity:
• Similarity:
• Continuity:
• Closure:
• Symmetry:
• Figure-ground:

The Binding Problem and Vision

• Different parts of the stimulus is processed in different stimuli but percienve the stimulus in the stimuli that it is
• The function is to focus or bind the stimuli
• Vision: light travels as a wave
• light is the function that enables the vision that can vary from 400-700nm
• brightness indicates reflectiveness in how objects can be seen from the eyes
• The color and hue is enabled by the wavelength

The Eye

• The reflected light enters the pupil
• and the cornea
• The photo receptors enable clear objects to be observed Normal vision is enabled thru the optical nerve

Retina and Perception Theory

• Consists of rods and cones that help the process and absorb light from the opti
• Rods help better see periphery and monochromatic
• Cones high acuity central vision
• damage results in blindness even if function normally
• damage in temporal lobe is object preception issues
• hubel and wiesel is important for cell in primary visuall cortex main
• Trichromatic theory color is dependent on 3 types of colors
• Theory blue or yellow, red and green

Vision and Color Theories

• Trichromatic theory states color vision depends on activity of three different color cone types: blue (S), green (M), and red (L)
• Color vision is related to opposing responses by blue and yellow, and red and green by the opponent-process theory

Color Blindness and After Images

• Trichromatic theory explains color blindness well such as humans being trichromatic(3 kinds of cones) Short medium long
• Dichromats(2 minds of cones) makes up more 12% makes or 0.1z% of femailes
• Typically in re
• After images can result color can be changed by what color the eyes saw
• Duall process- incorpations color proccesing

Parts of the ear that affects auditort processing

• sound is vibrartions fromm aur or meduim
• amplitude relates to loudness pitch
• 3 main parts of outer, inner and middle ear
• Middle part cochlea helps hair cells and membrandes is the middle functions for hearing,

Ear and Pitch

• vibration enable action poteinal to occut and sound helps different way sections to work
• Place theory shows vibrations the percpetions
• Higher order auditory processing

Talamus and Auditory

• Signals of ears are processed from cochlea for hearing and transeffected for processing to higher cortez
• talamus can have major deafness problems and conductive damage
• and major aging and hearing damage causes

Taste and Smell: Olfaction and Gustation

• Olfaction (smell) closely tied to taste
• Heavily linked to memmory and recognition
• Can sense world smell relationship
• Taste
  • Sensory receptor system for taste
• taste buds affect taste
• Bitterness
• Sourness
• Sweetness
• Saltiness Umami (savory)
• Cortex that help taste processing

Smell and Cilia

• chemical structures odors that moves through the air
• Olfactory structures are located in the nasal passagers Signals goes to Cortex Damage in ability to smell anomisa

The Flavour

• Flavour combines taste/smell and eating is tasteless
• Taste/smell interacts in orbitofrontal cortex for processing of smells/tastes
• Body Senses through touch, temp
• system helps touch and main

Key Parts of Senses

• Nociception is the function of pressure and objects with touch
• Hapsis is the perception of pain and temperature
• Proprioception is for limbs knowing limb place in splace
• And balance contorl by innner ear

Skin

• Skin is large and has organ receptors for touch outer layer Epidermis is the outter of skin comprised death, dermis below this and subscataunous- Mecanoreceptors is repsoncible fir stiuki to the skin

Mechanoreceptors

• Respond to simiuli skin
• Mechnoreceptors touch vibration skill indentation receptors of pain and temerature
• Distribitied across the body surface unevenly

Proprioception and Vestibular

• Proprioception is monitering parts of body can allow move
• Procriocetpors sense muscle strech and force
• the somatosensory cortex and vestibule
• Allows balnce to be maintained

Vestibular System and Sleep

• inner ear is vestibular system to know location of body relative to earth and orientation that help maintain and process balance, tilt and keep stable image Chapter 5 with study of What is consiousness? Our subjectivity and what we are thinking internally and externally. Why do we sleep and what sleep offers

What is Sleep For?

• The exact sleep prupose remains unclaer but sleep impacts memory and bodily harm

Circadian Rhythm and Sleep Deprivation

• Circadian rhythm changes in 24 hrs basis and alertness
• Regulate the surtachrimistain neuron collection which are 20 k neurons in hythalamus
• Snc is gland released to
• The more one sleeps the more decrease decrease increase vice cerse
• How much you must sleep. 32000 survey shows 7- 10 hrs per day. Sleep Deprival- After more than 4 days one starts hallunciting

How Sleep Deprivation Impacts Health

• Sleep loss affects the brain causing depression and difficulty to learn
• Can affect immume system function and affect weight

Stages of Sleep and EEG

• 5 tages sleep, and stages has eeg and defnied different
• Getting sleepy get drowsy different from beta waves
• Stage 1 like transition 5-10 min brain decrease 50% myclonic jerk and ipnagogiac imagery occur in state

Stage 2 and the other stages

• typically 10-25 mins 65 percent of sleep occurs
• theat activity common, and complex
• Stage 3 slow wave after 10 -30 is the sleep occur diferrece is the delta amount the less the rest alcohol represed sleep

Rapid Eye Movement States

• 15-30 stage after the stage process start over
• rem is 20-25 percent of the sleep cycle eeg activity higher similar to awake state, with sleep dreaming and eye movement

Dreaming And Lucid Dreaming

• dream occuts are simialr to sleep more common is Rem, Middle Ear mucle activity during Rem and Body is perazlied Lucid dreams is when one is aware that is dreaming

Sleep Disorders

• 30-50 peoepl problems costs of rem and insomina affects 9-1\5 pereccnt of people, and mental state