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Brain, Sensation &
Perception - Coggle Diagram
Brain, Sensation &
Perception
The Nervous System
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Peripheral Nervous System (PNS)
- PNS transmits information to and from CNS
- Contains all portions of NS (outside brain & spinal cord) right down to nerves in the tips of fingers and toes
- Includes sensory & motor nerves connecting CNS to the rest of the body
Autonomic Nervous System
- Controls the functioning of internal organs (e.g., heart, stomach) glands and blood vessels
- May be overridden
- Sympathetic
- Parasympathetic
Somatic Nervous System
- Sensory receptors (feel)
- Skeletal system (actions)
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Communications
Neurons
Transmit information to, from, and within the CNS
Dendrites
Branch-like structures that receive information from other neurons and transmit it to the cell body
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Axon
Neuron’s tube-like extension that transmits messages to other neurons, muscles or gland cells
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Myelin sheath
Fatty insulation surrounding the axon, helps speed the neural impulses
- Myelin sheath degeneration leads to multiple sclerosis (communication to muscles slows, loss of muscle control)
Communicates within neuron via Action Potential
- A brief electrical charge that travels down an axon
- Information is pushed through the axon based on a process of positive and negative charges of electrical atoms (ions)
Communication between neurons done via neurotransmitter
- A chemical substance that is released by a transmitting neuron at the synapse and that alters the activity of a receiving neuron
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Dopamine (DA)
Influences movement, learning, attention, sensations of pleasure
Serotonin (5-HT)
Affects mood, appetite,
sleep, anxiety
Acetylcholine (ACh)
Enables muscle action,
learning and memory
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Glia Cells
Hold neurons together, as well as nourish,
insulate, and protect them
Endocrine System (ES)
Pituitary gland
Located in the brain, secretes human growth hormone
Pineal gland
Located near the base of the cerebrum, secretes melatonin (biological rhythms & sleep)
Thyroid gland
Found in the neck, secretes thyroxin (growth & metabolism)
Pancreas
Controls the levels of sugar in the blood, secretes insulin and glucagon
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Adrenal glands
Located at top of each kidney secrete over 30 hormones (corticoids/steroids) to control stress reactions
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Mapping the Brain
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Brain Stimulation
Deep Brain Stimulation (DBS)
Stimulating brain from the inside (invasive) – treatment for Parkinson’s Disease, Seizures, Chronic Pain
Transcranial Magnetic Stimulation (TMS) Stimulating brain from the outside with magnetic impulses (non-invasive) – PTSD & depression
Mapping Structures
Computed Tomography (CT)
Using X-rays to map brain “slices” (tumours, stroke damage, metal)
Magnetic Resonance Imaging (MRI)
Using magnetic fields & radio receivers for detailed (and 3D) imaging of brain tissue
Mapping Functions
Electroencephalogram (EEG)
Amplified recording of the waves of electrical activity sweeping across the brain’s surface, measured by electrodes placed on the scalp
Positron Emission Tomography (PET)
Visual display of brain activity that detects where a radioactive form of glucose goes while the brain performs a given task
Functional MRI (fMRI)
Tracking changes in blood oxygen levels (increased levels=increased functioning) to study brain activity linked with specific thoughts & behaviour
Brain Structures
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Midbrain
Connects hindbrain and forebrain, important for sensory & motor functions
Forebrain
Higher functioning (thinking, decision-making)
Limbic System
Emotions, motivation, memory & learning
Thalamus
- Brain’s sensory control centre
- Receives information from all senses (except smell) and routes it to higher brain regions responsible for vision, hearing, touch & taste
Hypothalamus
Regulates survival needs (thirst, hunger, sleeping, body temperature) & emotions (controls pituitary gland- hormones)
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Cerebrum
Largest brain structure, controls sensory, motor and cognitive processes
Cerebral hemispheres
- The 2 hemispheres communicate via the corpus callosum
- Right hemisphere controls left side of body & Left hemisphere controls right side of body
Cerebral cortex
The outer layer of the cerebrum (grey matter), covering the cerebral hemispheres responsible for higher mental functions.
Frontal lobes
- Complex decision-making, planning, memory, personality and social judgement.
- Includes motor cortex & Broca’s area (speech production)
Temporal lobes
- Hearing (primary auditory cortex; auditory association cortex);
- Wernicke’s area (meaning of words)
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Sleep
- Circadian rhythm is controlled by brain
- Suprachiasmatic Nucleus (SCN) in hypothalamus regulates:
- Melatonin from pineal gland. Increases in dark conditions
- Seratonin. Increases when awake
- Required for restoration, repair and mental function
N1
Light sleep, drifting in & out consciousness
N2
Body temperature & heart rate ↓, breathing shallow, minor noises won’t wake
N3 & N4
Brreathing & pulse ↓, muscles relax, deep sleep, hard to wake
REM
Brain active, body inactive (paradoxical sleep)
Sleep deprivation
- Short term
- Reduced attention
- Irritable
- Long term
- Hallucinations
- Mood disorders
- Heart diseases
Problems
- Insomnia: recurring problems falling or staying asleep
- Sleep Apnea: breathing periodically stops (≥10secs) causing choking or gasping
- Narcolepsy: irresistible and unpredictable day time attacks of sleepiness or actual sleep, lasting 5-30mins
- Night Terrors: high arousal & appearance of being terrified, during N3 sleep (unlike nightmares), seldom remembered
- REM behaviour disorder: dream-enacting behaviour; physically act out vivid, often unpleasant dreams with vocal sounds and sudden, often violent arm and leg movements during REM sleep
Psychoactive Drugs
- Stimulants (amphetamines, cocaine, nicotine, caffeine)
- Depressants (barbiturates, benzodiazepines, alcohol)
- Narcotics (opioids)
- Hallucinogens (manufactured: LSD, PCP, MDMA – also stimulant)
- Marijuana (non-manufactured; cannabis)
Effects include
- Brain damage
- Tolerance to drugs
- Withdrawal symptoms
- Addiction
- Bad stuff
Sensation and Palpation
Vision
- Hue
- Brightness
- Saturation
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Smell
- Olfaction (olfactory sense)
- The ability to smell odors (chemicals: substance molecules suspended in air)
- Sense organ: nose
- Olfactory receptor cells
- Specialized neurons embedded in a tiny patch of mucous membrane in the upper part of nasal passage, just beneath eyes
- Olfactory bulbs
- Areas of brain located just above sinus cavity and just below frontal lobes that receive information from olfactory receptor cells
Hearing receptors
Hair cells (topped by cilia) embedded in the basilar membrane of the organ of Corti, in the interior side cochlea
Measurement
Psychophysics
Studies the relationships between the physical characteristics of stimuli and their effects on psychological experiences
Absolute Thresholds
The minimum stimulus energy needed to consciously detect a particular stimulus 50% of the time
Difference Thresholds
The minimum difference between two stimuli required for detection 50% of the time
Signal Detection Theory
Detection of sensory signal comprises a sensory process & a decision process, varies with motivation, alertness & expectation
Adjustment
Habituation
Tendency of brain to stop attending to constant, unchanging information so that it can focus on what matters (e.g., A/C noise)
Sensory Adaptation
Diminished sensitivity of sensory receptor cells to unchanging or constant stimulus (e.g., heavily perfumed person)
Sensory Deprivation
Absence of normal levels of sensory stimulation, effects vary depending on duration and person’s interpretations (e.g., involuntary vs voluntary)
Sensory Overload
Managed by process of selective attention (focus on what’s important); may also deprive of information that is needed (e.g., texting while walking)
Somesthetic Senses
Skin senses
Touch, pressure, temperature & pain
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Vestibular senses
Sensations of movement, balance, &
body position
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