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MAJOR ISSUE |
THE FIELD OF BIOLOGICAL PSYCHOLOGY
➢ BIOLOGICAL PSYCHOLOGY
○ emphasizes that the goal is to relate biology to issues of psychology. ○ study of the physiological, evolutionary, and developmental mechanisms of behavior and experience. ○ is approximately synonymous with the terms biopsychology, psychobiology, physiological psychology, and behavioral neuroscience. ○ S Biological psychology deals mostly with brain activity. Figure Intro.2 offers a view of the human brain from the top (what anatomists call a dorsal view) and from the bottom (a ventral view). BIOLOGICAL EXPLANATIONS OF BEHAVIOR ➢ PHYSIOLOGICAL EXPLANATION ㄧ relates a behavior to the activity of the brain and other organs. ㄧ Area of the brain enables bird to sing ➢ ONTOGENETIC EXPLANATION (abt environment) ㄧ describes how a structure or behavior develops, including the influences of genes, nutrition, experiences, and their interactions. ㄧ Describes the development of the structure or behavior ㄧ Ex. why genes and environment are both necessary for a bird to sing. ➢ EVOLUTIONARY EXPLANATION (more on structure) ㄧ reconstructs the evolutionary history of a structure or behavior. ㄧ Examines a structure or a behavior in terms of evolutionary history. ㄧ Ex. two different species of birds with similar songs have the same ancestors. ➢ FUNCTIONAL EXPLANATION (what's the purpose of being alert) ○ describes why a structure or behavior evolved as it did. ○ Ex. singing improves birds chance of mating
FIELDS OF SPECIALIZATION
● Neuroscientist ● Behavioral Neuroscientist (almost synonyms: psychobiologist, biopsychologist, or physiological psychologist) ● Cognitive Neuroscientist ● Neuroscientist ● Psychophysiologist ● Neurochemist ● Comparative psychologist (almost synonyms: ethologist, animal behaviorist) ● Evolutionary psychologist (almost synonym: sociobiologist) ● Clinical Psychologist ● Counseling Psychologist ● School Psychologist ● Neurologist ● Neurosurgeon ● Physical therapist ● Occupational therapist ● Social Worker
THE CELLS OF THE NERVOUS SYSTEM |
NEURONS AND GLIA
➢ Neurons - receive information and transmit it to other cells.
- that is specialized for information processing and communication. ➢ The adult human brain contains approximately 85 billion neurons, on average SANTIAGO RAMON Y CAJAL (1852–1934) ➢ was the first to demonstrate that the individual cells comprising the nervous system remained separated. ➢ Spanish investigator and Charles Sherrington are the main founders of neuroscience ➢ His detailed drawings of the nervous system are still considered definitive today. THE STRUCTURES OF AN ANIMAL CELL ➢ MEMBRANE (or plasma membrane) 一 a structure that separates the inside of the cell from the outside environment. ➢ NUCLEUS 一 the structure that contains the chromosomes. ➢ MITOCHONDRION (plural: mitochondria) 一 the structure that performs metabolic activities, providing the energy that the cell uses for all activities. ➢ RIBOSOMES 一 the sites within a cell that synthesize new protein molecules. ➢ PROTEINS 一 provide building materials for the cell and facilitate chemical reactions.
➢ ENDOPLASMIC RETICULUM
一 a network of thin tubes that transport newly synthesized proteins to other locations. ➢ MOTOR NEURON 一 receives excitation through its dendrites and conducts impulses along its axon to a muscle. ➢ SENSORY NEURON 一 is specialized at one end to be highly sensitive to a particular type of stimulation, such as light, sound, or touch. ➢ DENDRITES = receives 一 branching fibers that get narrower near their ends. 一 part of a neuron that receives incoming signals ➢ SYNAPTIC RECEPTORS 一 the dendrite receives information from other neurons. ➢ DENDRITIC SPINES ㄧ short outgrowths that increase the surface area available for synapses ㄧ that provide energy to the cell by transforming pyruvic acid and oxygen into molecules of adenosine triphosphate (ATP). ➢ CELL BODY OR SOMA ㄧ contains the nucleus, ribosomes, and mitochondria. Most of a neuron’s metabolic work occurs here. Also responsible for the metabolic work. ➢ AXON ㄧ a thin fiber of constant diameter,. axon conveys an impulse toward other neurons, an organ, or a muscle.
THE CELLS OF THE NERVOUS SYSTEM & NERVE IMPULSE |
S - sensory A - afferent M - motor E - efferent ➢ AXON = sends ― regenerates an impulse at each point ― usually responsible for carrying signals to other neurons. ➢ ELECTRICAL GRADIENT OR POLARIZATION ― happens when the membrane is at rest the membrane maintains an electrical gradient ― at rest, there are more positively charged ions outside the cell relative to the inside. This creates a difference in charge across the membrane. ○ electrical potential inside the membrane is slightly negative with respect to the outside, mainly because of negatively charged proteins inside the cell. ➢ ELECTROCHEMICAL GRADIENT ― ionic imbalance ➢ RESTING POTENTIAL ― difference in voltage ➢ MICROELECTRODE ― a biopotential electrodes with an ultrafine tapered tip that can be inserted into individual biological cells ― when the membrane is at rest, the sodium and potassium channels are closed ➢ SODIUM - POTASSIUM PUMP ― a protein complex, repeatedly transports THREE SODIUM IONS out of the cell while drawing TWO POTASSIUM IONS into it. The sodium–potassium pump is an active transport that requires energy. ➢ CONCENTRATION GRADIENT ― the difference in distribution of ions across the membrane
➢ POTASSIUM
― is subject to competing forces. Potassium is positively charged and the inside of the cell is negatively charged, so the electrical gradient tends to pull potassium in. ➢ ACTION POTENTIAL ― messages sent by axons ― rapid depolarization of the neuron ― If the stimulation is strong enough, the signal is transmitted along the entire length of the axon in a phenomena ➢ HYPERPOLARIZATION (INHIBITOR) ― increased polarization or the difference between the electric charge of two places ○ various ions including Sodium, Potassium, and Chlorine are unequally distributed between the inside and the outside of the cells. ➢ DEPOLARIZE (EXCITATORY) ― reduces its polarization toward zero ➢ THRESHOLDS OF EXCITEMENT ― any stimulation beyond a certain level and results in a mass depolarization ○ when a neuron is NOT sending a signal, it is considered to be AT REST. ○ In a typical neuron in ITS RESTING STATE, the concentration of SODIUM IONS is HIGHER OUTSIDE the cell than inside ○ with more ions inside the cell than outside, this ionic separation occurs right at the cell membrane. ➢ MEMBRANE POTENTIAL ― difference in total charge inside and outside of the cell. At rest, when no signals are being transmitted, the neuronal membrane has a resulting potential of approx -70 MILLIVOLTS. This means that the inside of the cell is approx 70 MILLIVOLTS LESS POSITIVE THAN THE OUTSIDE. ➢ SYNAPTIC VESICLES ㅡ where neurotransmitter are stored OUTSIDE CELL = NET POSITIVE CHARGE INSIDE CELL = NET NEGATIVE CHARGE WITHIN THE NEURON = ELECTRICAL NEURON TO NEURON = CHEMICAL
NERVE IMPULSE |
➢ SYNAPSE
ㅡ junction between two neurons at which information is transferred from one to another ➢ RESTING MEMBRANE POTENTIAL ― the point where the cell has achieved electrochemical equilibrium - the concentration gradient and the electro gradients for each ion is equal & opposite ➢ ION CHANNEL ― ions move through channels by passive diffusion along their concentration gradient; some ion channels are always open, but many require signals to tell them to open or close. ➢ VOLTAGE GATED ION CHANNELS ― only opens when the membrane potential reaches a certain value. ➢ LIGAND - GATED ION CHANNELS ― triggered to open when they are bound by a specific molecule ➢ MECHANICALLY - GATED ION CHANNELS ― open in response to physical forces, such as changes in length or changes in pressure ALL-OR-NONE LAW ― the amplitude and velocity of an action potential are independent of the intensity of the stimulus that initiated it, provided that the stimulus reaches the threshold. ― puts constraints on how an axon can send a message. ― THICKER AXONS convey action potentials at greater velocities, and also convey more action potentials per second. THE MOLECULAR BASIS OF THE ACTION POTENTIAL The chemical events behind the action potential may seem complex, but they make sense if you remember three principles:
- At the start, sodium ions are mostly outside the neuron , and potassium ions are mostly inside.
- When the membrane is depolarized, sodium and potassium channels in the membrane open.
- At the peak of the action potential, the sodium channels close. ➢ PROPAGATION OF THE ACTION POTENTIAL ― describes the transmission of an action potential down an axon ➢ SHEATHS OF MYELIN ― insulating material composed of fats and proteins
➢ MYELINATED AXONS
― found only in vertebrates, are covered with layers of fats and proteins. The myelin sheath is interrupted periodically by short sections of axon called NODES OF RANVIER ➢ SALTATORY CONDUCTION (saltare) ― jumping of action potentials from node to node REFRACTORY PERIOD ➢ REFRACTORY PERIOD ― resists the production of further action potential ― during which time the neuron resist upon another action potential ➢ ABSOLUTE REFRACTORY PERIOD ― the first part, the membrane cannot produce another action potential, regardless of stimulation. ― RELATIVE REFRACTORY PERIOD ― the second part, a stronger than usual stimulus is necessary to initiate an action potential. The refractory period depends on two facts: ● sodium channels are closed ● potassium is flowing out of the cell at a faster-than-usual rate. LOCAL NEURON ― Neurons without an axon exchange information with only their closest neighbors. ― depolarizes / hyperpolarizes in proportion to the stimulation ➢ GRADED POTENTIAL ― a local neuron receives information from other neurons ― membrane potentials that vary in magnitude and do not follow the all-or-none law ➢ AXON HILLOCK ― a swelling and where exit of the soma ― cone-shaped segment of axon located at the junction of the axon and cell body that is specialized for the generation of action potentials. ➢ ANTEROGRADE TRANSPORT - movement of materials from the cell body of a neuron to the axon terminal along the microtubules. ➢ RETROGRADE TRANSPORT - movement of material from the axon terminal back to the cell body via the cell's system of microtubules.
NEUROTRANSMITTER & RESEARCH METHODS |
● DEEP BRAIN STIMULATION
- can be used in Parkinson's disease LESIONS
- an injury to neural tissue and can be either naturally occurring or deliberately produced. ● LESION ANALYSIS
- to assess the probable function of an area ● ABLATION
- surgical removal of neural tissue ● BIOCHEMICAL METHODS
- use of chemical and microdialysis GENETIC METHODS ● TWN STUDIES
- natural comparison provides a fair amount of control because we can assume that twins enjoy similar prenatal and postnatal environments. ● CONCORDANCE RATES
- type of statistical probability. ➢ ADOPTION STUDIES ● HERITABILITY - the amount that a trait varies in a population due to genetics, is still influenced by the environment. ➢ STUDIES OF GENETICALLY - MODIFIED ANIMALS ● KNOCKOUT GENES - take the place of the normal genes but fail to produce the specific protein. ● EPIGENETICS - gene expression due to external factors NEUROTRANSMITTER
- chemical substance that communicate from one neuron to another significance : mood, bipolar disorder, schizophrenia ● SYNAPTIC VESICLES
- contain neurotransmitters in the axon ● SYNAPTIC CLEFT
- space between the presynaptic and postsynaptic neurons.
● RECEPTOR SITE
- on dendrite of receiving neuron ● EXCITATORY NEUROTRANSMITTER
- cause other neurons to five ● INHIBITORY NEURONS
- prevent other neurons from firing ● ACETYLCHOLINE (ACH)
- controls muscle contractions
- paralysis
- prevalent in hippocampus
- memory
- Alzheimer's disease ● DOPAMINE
- pleasure, voluntary, movement, learning, memory
- parkinson's disease
- schizophrenia
NEUROTRANSMITTER & RESEARCH METHODS |
● NOREPINEPHRINE
- excitatory neurotransmitter
- accelerates heart rate, affects eating, linked to activity levels, learning, and remembering - mood disorders - depression - bipolar disorder
S - selective S - selective
N - norepinephrine S - serotonin
R - reuptake R - reuptake
I - inhibitor I - inhibitor
● SEROTONIN
- emotional arousal and sleep
- eating disorders
- alcoholism
- depression
- aggression
- insomnia ● GAMMA - AMINOBUTYRIC ACID (GABA)
- inhibitory may help relax anxiety reactions
- depression ● ENDORPHINS
- occur naturally within the brain and bloodstream
- inhibit pain
- may be connected to indepence to pain
- runner's high
ANATOMY & WAKEFULNESS AND SLEEP |
THE BRAIN
HINDBRAIN
— the posterior part of the brain, consists of:
**- medulla
- pons**
- cerebellum. — certain central structures of the forebrain constitute the brainstem MEDULLA or MEDULLA OBLONGATA — enlarged extension of the spinal cord. — motor nerves, the head and the organs connect to the medulla and adjacent areas by 12 pairs of cranial nerves — involve in heartbeat — CRANIAL NERVES - originating in the medulla control vital reflexes such as breathing, heart rate, vomiting, salivation, coughing, and sneezing. PONS — involve in movement — lies anterior and ventral to the medulla. — axons from each half of the brain cross to the opposite side of the spinal cord
CEREBELLUM
— balance and coordination — a large hindbrain structure with many deep folds. It has long been known for its contributions to the control of movement MIDBRAIN — in the middle of the brain TECTUM — root of the midbrain — covers the tegmentum SUPERIOR AND INFERIOR COLLICULUS — both are swellings on each side of the tectum ➢ SUPERIOR COLLICULUS — for vision ➢ INFERIOR COLLICULUS — for hearing TEGMENTUM — intermediate level of the midbrain — covers several other midbrain structures. SUBSTANTIA NIGRA — gives rise to a dopamine-containing pathway that facilitates readiness for movement. FOREBRAIN — most prominent part of the mammalian brain, consists of two cerebral hemispheres, — each hemisphere is organized to receive sensory information , mostly from the contralateral (opposite) side of the body.It controls muscles, mostly on the contralateral side, by way of axons to the spinal cord and the cranial nerve nuclei.
ANATOMY & WAKEFULNESS AND SLEEP |
CEREBRAL CORTEX
— outer portion of the forebrain LIMBIC SYSTEM — form a border around the brainstem. — the limbic system includes: — olfactory bulb — hypothalamus — hippocampus — amygdala HYPOTHALAMUS — is essential for control of eating, drinking, temperature control, and reproductive behaviors. AMYGDALA
- part of the circuit that is most central for evaluating emotional information especially with regard to fear
- THALAMUS — a pair of structures (left and right) in the center of the forebrain — most sensory information goes first to the thalamus, which processes it and sends output to the cerebral cortex. DIENCEPHALON — section distinct from the telencephalon TELENCEPHALON
- the rest of the forebrain
HYPOTHALAMUS
— a small area near the base of the brain just ventral to the thalamus — has widespread connections with the rest of the brain. — conveys messages to the pituitary gland, altering its release of hormones PITUITARY GLAND — an endocrine (hormone-producing) gland attached to the base of the hypothalamus BASAL GANGLIA — a group of subcortical structures lateral to the thalamus — damage to the basal ganglia impairs movement BASAL FOREBRAIN NUCLEUS BASALIS — receives input from the hypothalamus and basal ganglia and sends axons that release acetylcholine to widespread areas in the cerebral cortex — a key part of the brain's system for arousal, wakefulness and attention HIPPOCAMPUS — a large structure between the thalamus and the cerebral cortex is critical for certain types of memories, especially memories for individual events. It is also essential for monitoring where you are and where you are going. THE VENTRICLES — four fluid-filled cavities within the brain CHOROID PLEXUS — along the walls of the for ventricles produce cerebrospinal fluid (CSF) ➢ CEREBROSPINAL FLUID (CSF)
- a clear fluid similar to blood plasma ➢ MENINGES
- membranes that surround the brain and spinal cord ➢ HYDROCEPHALUS
- skull bones spread, causing an overgrown head
- can lead to mental retardation ➢ DORSAL
- toward the back
ANATOMY & WAKEFULNESS AND SLEEP |
WHY SLEEP?
FUNCTIONS OF SLEEP INCLUDE:
— Restoration of the brain and body — Energy conservation — Memory consolidation / learning RESTORATION OF THE BRAIN AND BODY ● MODERATE SLEEP DEPRIVATION CAN RESULT IN: — Impaired concentration — Irritability — Hallucinations — Tremors — Unpleasant mood — Decreased immune system function ● OPTIMAL SLEEP TIME: 8-10 hrs ● PROLONGED SLEEP DEPRIVATION IN LABORATORY ANIMALS RESULTS IN: — Increased metabolic rate, appetite and body temperature — Immune system failure — Decrease in brain activity ENERGY CONSERVATION ● EVOLUTIONARY THEORY OF SLEEP : ● THE FUNCTION OF SLEEP IS TO CONSERVE ENERGY BY: — Decreasing body temperature 1-2 celsius degrees in mammals — Decreasing muscle activity ● Sleep is analogous to the hibernation of animals WHY DREAMS? ACTIVATION SYNTHESIS HYPOTHESIS ● ACTIVATION-SYNTHESIS HYPOTHESIS: dreams begin with spontaneous activity in pons — Pobs activates many part of cortex — Cortex synthesizes story from patterns of activation — Normal sensory information cannot complete with the self-generated stimulation and hallucinations result THE CLINICO-ANATOMICAL HYPOTHESIS ● Clinico-anatomical hypothesis : dreams are similar to thinking, just under unusual circumstances ● Dreams begin with arousing stimuli that are generated within the brain ● Stimulation is combined with recent memories and current sensory stimulation RHYTHMS OF WAKING AND SLEEP ● ENDOGENOUS: generated from within ● ENDOGENOUS CIRCANNUAL RHYTHMS: internal mechanisms that operate on an annual cycle exp: birds migratory patterns animals storing food for winter ● ENDOGENOUS CIRCADIAN RHYTHMS: internal mechanisms that operate on an approx. 24 hour cycle : — Sleep / wake cycle — Frequency of eating and drinking — Body temperature — Secretions of hormones — Volume of urination — Sensitivity to drugs THE CIRCADIAN RHYTHM (AKA: THE BIOLOGICAL CLOCK) ● FREE-RUNNING RHYTHM : rhythm that occurs when no stimuli reset or alter it ● Human circadian clock generates a rhythm slightly longer than 24 hours when it has no external cue to set it ● Most people can adjust to 23- or 25- hour day but not to a 22- or 28- hour day BIOLOGICAL CUES ● SUNRISE = light + increasing temperature ● SUNSET = dark + decreasing temperature RESETTING THE BIOLOGICAL CLOCK ● PURPOSE OF CIRCADIAN RHYTHM: to keep out internal workings in phase with the outside world ● Light is critical for periodically resetting our circadian rhythm ● ZEITGEBER: term used to describe any stimulus that resets circadian rhythms: exercise, noise, meals, temperature and more
ANATOMY & WAKEFULNESS AND SLEEP |
JET LAG
— disruption of circadian rhythms due to crossing time zones — characterized by sleepiness during the day, sleeplessness at night, and impaired concentration ➢ HIPPOCAMPUS
- a brain area important for memory. ENDOGENOUS CIRCADIAN RHYTHMS — internal mechanism — last about a day RHYTHMS OF WAKING AND SLEEP BIOLOGICAL MECHANISM ➢ SUPRACHIASMATIC NUCLEUS (SCN)
- part of the hypothalamus
- SCN generates circadian rhythms itself in a genetically controlled manner.
- light resets the SCN via a small branch ➢ RETINOHYPOTHALAMIC PATH
- from retina to the SCN, alters the SCN's settings
- travels directly from the retina to the SCN ➢ PINEAL GLAND
- SCN regulates the pineal gland
- secretes melatonin. ➢ MELATONIN
- a hormone that increases sleepiness STAGES OF SLEEP AND BRAIN MECHANISMS ➢ ELECTROELEPHLOGRAPH (EEG)
- records an average of the electrical potentials of the cells and fibers in the brain areas nearest to each electrode on the scalp ➢ POLYSOMNOGRAPHY
- combination of EEG and eye-movement records ➢ ALPHA WAVES
- characteristic of relaxation,not of all wakefulness. ➢ STAGE 1 SLEEP
- is when sleep has just began ➢ STAGE 2 SLEEP — K-COMPLEX - a sharp wave associated with temporary inhibition of neuronal firing — SLEEP SPINDLE - a burst of 12- to 14-Hz waves for at least half a second. ➢ STAGES 3 and 4
- constitute with slow wave sleep (SWS) — SLOW WAVE SLEEP - indicates that neuronal activity is highly synchronized. ➢ RAPID EYE MOVEMENT SLEEP (REM) — also known as PARADOXICAL SLEEP — periods of rapid eye movements occur during sleep — the postural muscles of the body, including those that support the head, are more relaxed during REM than in other stages. — REM is deep sleep. — REM is associated with dreaming REM DEPRIVATION RESULTS IN: POSSIBLE FUNCTIONS OF REM SLEEP: SLEEP DISORDERS ➢ INSOMNIA
- inability to fall asleep or stay asleep causes: noise, uncomfortable temperatures, stress, pain, diet, and medications. treatment: ➢ SLEEP APNEA
- periodic inability to breathe while sleeping
- can result in cognitive impairment it there is a loss of neurons due to insufficient oxygen level causes: genetics, hormones, and old-age deterioration of the brain mechanisms that regulate breathing, and obesity, treatment: common treatment is a mask that covers the nose and delivers air under enough pressure to keep the breathing passages open. ➢ NARCOLEPSY
- condition characterized by frequent periods of sleepiness during the day **4 symptoms:
- gradual or sudden attack of sleepiness**
- occasional cataplexy ーan attack of muscle weakness while the person remains awake.
- sleep paralysis - an inability to move while falling asleep or waking up.
- hypnagogic hallucinations - dreamlike experiences that the person has trouble distinguishing from reality. PERIODIC LIMB MOVEMENT DISORDER
