Biopsychology- Recording The Brain,The Peripheral Nervous System And Hormones Flashcards
Non- imaging techniques
-Studying lesioned and brain damaged patients- invasive- not ethical
-Direct cortical
Non imaging techniques
-Studying lesioned and brain-damaged patients-
-No pre measures of behaviour or cognition
- brain complicated- hard to distinguish between If the behaviour is caused by connections in the brain or the damage
-Direct cortical stimulation- stimulate different areas of the brain and see behaviour- help mapping the brain- unethical
-Transcranial magnetic stimulation- device placed next to skull- has strong magnetic field which effects the neurons- mainly study cortex
less invasive
Used with people who get migraines and depression
Brain imaging-two types
-Structural brain imaging (CT,MRI)
-Structure of the brain regions
-Brain abnormalities
-Individuals and group differences
Functional brain imaging (PET,fMRI)
-Brain at work
-Structure involved in certain behaviours
-Explain group differences
Computerised Axial Tomography (CAT)
- X-ray of brain
-Structure, not function
-Used to detect tumors,degenerative diseases,the location of strokes
Magnetic resonance imaging (MRI)
-Structure rather than function
-Certain atoms spin
-Orientation normally random
-Apply magnetic field they lined up
-Apply radio frequency they wobble
-Turn off frequency atoms release energy measured by detector
Structural scans
Group differences
Diagnosis
Function- Positron Emission Tomography
-Active cells require more blood and fuel
-Radioactive substance injected into the individual
-Most common -radioactive 2-deoxyglucose (2-DG)
(But can vary depending on what we want to measure eg, blood flow, blood volume, neurotransmitter)
-As radioactive isotopes travel to the brain and as they decay they emit positrons
-Detectors can locate emitted positrons to measure their position
Functional- Functional Magnetic Resonance Imaging (fMRI)
-Active brain tissue uses more blood (ie- glucose/oxygen)
-Oxygen level in blood translates how active a brain area is
-Measures the increase in oxygen flow to active areas of the brain
-Indirect measure of neuronal activity
fMRI and PET
-Same as MRI
-Very goos spatial resolution
-Temporal resolution (how quickly you see the scan) okay
PET
-Radioactive tracer,risk of irritation
-Not suitable for pregnant women and children
-Good spatial resolution
-Poor temporal resolution
-Long scan time
-Very expensive
Spatial resolution
How clear the scan is
MRI can be colour enhanced which improves the resolution
Electroencephalograph (EEG)
-Detects the electrical activity associated with functioning neurons
-Electrodes (usually >8) are placed on the scalp
-Output is amplified (and subjected to sophisticated analyses)
EEG- waves
-High amplitude and low frequency
-Sleep,drowsiness, unconsciousness
Low amplitude and high frequency- arousal, excitement, alertness
Waves - EEG
Alpha (8-12Hz)
Alert but relaxed,not drowsy or agitated but calm and at ease
-Linked to -extroversion,meditation and relaxation
Beta (13-30Hz)
Alert or anxious with eyes open,listening,and processing information
Also presents in REM sleep
Delta (< 4 Hz)
Deep sleep
Decrease when individuals need to focus to perform at their best, in ADD then increase rather than decrease
Theta (4-8 Hz)
Reflects state between wakefulness and sleep,strong daydreaming and fantasising
Increased pattern in psychopaths
Somatic nervous system (SNS)
-Interacts with external environment
-Afferent- nerves - sensory signals
-Skin,skeletal,muscles,eye,ears -> CNS
Efferent nerves - motor signals
CNS-Muscles
Automic nervous system (ANS)
Regulates the internal environment
Largely involuntary
Afferent nerves sensory signals
Organs –> CNS
Efferent nerves motor signals
CNS–> organs
Two types of efferent nerves
Sympathetic- triggered when engaging in active behaviour, stimulate,organise and mobilize energy resources to the organs the require the most fuel during a threatening situation
Parasympathetic - active in times of relaxation,generally act to extract and conserve energy
Sympathetic nervous system
-Involved in ‘fight or flight’
-Release of noradrenaline and adrenaline
-Stimulated the heart
-Raises blood pressure
-Dilates pupils
-Dilates trachea and bronchi
-Increased sweating
-Directs blood from the skin to the skeletal muscles and brain
-Inhibits digestives systems
-Inhibits saliva flow
Inhibits bladder contraction
The fight or flight response
-Walter cannon 1929
-Automatic inborn response that occurs because of activity in the sympathetic division of the autonomic nervous system
-Prepared the body to face or escape from the perceived danger
-Not unique to humans
Parasympathetic nervous system
Involved in ‘rest and digest’ response
-Release of Acetylcholine
-Slows heart beat
-Constricts pupils
-Increases blood to the stomach to assist digestion and assist In the absorption of nutrients from food
Push- pull mode
-Although both divisions are in opposition
-They both work to a varying degree
-Always some activity in both branches
-Said to have a push-pull relationship
Parasympathetic and sympathetic
Parasympathetic
-Slows flow of saliva
-Slows heartbeat
-Constricts bronchi
-Stimulates peristalsis and secretion
-Stimulated release of bile
-Contracts bladder
Sympathetic
-Dialates pupils
-Inhibits flow of saliva
-Accelerates heartbeat
-Dialates bronchi
-Inhibits peristalsis and secretion
-Conversion of glycogen and glucose
-Secretion of adrenaline and noradrenaline
-Inhibits bladder contraction
Principles of sympathetic and parasympathetic functioning
- sympathetic nerves stimulate,organise and mobilise energy resources in threatening situations, parasympathetic nerves act to conserve energy
-each autonomic target receives opposing sympathetic and parasympathetic input, its activity is thus controlled by relative levels of sympathetic and parasympathetic activity
-Sympathetic changes are indicative of psychological arousal,parasympathetic charges and indicative of psychological relaxation
Integration of ANS and SNS
-Two systems work together
-Example- stranger following you
-Information from senses to the brain (SNS)
-Make desicion to run
-Brain sends information back to the muscle of the leg (SNS)
-Brain sends information to internal organs to support the sudden activity
General adaptation syndrome (Selye,1974)
-The response to stress is considered to be an innate drive of living organisms to maintain internal balance Ie homeostasis
-Selye proposed a three-staged stress response
Alarm reaction- awareness of a stressor is the initial response which can cause activation of SNS. Blood pressure and heart rate raise to much higher than normal levels. This arousal cannot be maintained for long periods of time
Stage of resistance the body tries to adapt to a stressor that has not subsided In spite of resistance efforts made during the alarm stage. Arousal reduces but is still higher than normal. This stage of mobilisation of bodily defenses cannot last indefinitely without the organism becoming vulnerable to illness. Body compensates by hormone release and builds a resistance
Stage of exhaustion- exhaustion would occur if the resistance stage lasts too long,resulting in depletion of bodily resources and energy . Hormone secretion has negative effects on the body. The ability to resist stress declines and increased likelihood of diseases of adaption such as cardiovascular disease, arthritis, asthma is proposed
Hormones
Hormones - Greek word ‘hormon’ meaning ‘to excite’
Chemicals which are stored and secreted by specialised glands in the body named the endocrine gland
- travel though the bloodstream to their target region where they exert an effect
-Act on the brain and the body very early development and surfing puberty to shape physiology and behaviour
-As adults they continue to influence physiology and aspects of behaviour
Major endocrine glands
Pineal gland
Hypothalamus
Pituitary gland
Thyroud and parathyroids
Adrenal glands
Pancreas
Ovaries
Testes
Berthold (1849)
-First endocrinological experiment
-Castrated young roosters noted changes in behaviour and physiology- calmer , less aggressive
-When testes were reimplanted the birds regained their normal behaviour and psychological development - even if given a different roosters
Endocrine glands and their hormones
2 major classes of hormones
1- protein hormones
Made from individual amino acid building block
2- steroid hormones
Created from cholesterol in the diet
Protein hormones
Insulin- manufactured in the pancreas, increases the entry of glucose into the cell and the storage of fats
Glucagons- made in the pancreas, increases the conversion of stored fats to blood glucose
Leptin- produced by the fat cells, informs the brain how much fat is contained in the body. High leptin- levels = decreased appetite,low leptin- levels= increased appetite, low bodily activity (to save energy) and reproductive function (menstruation) ceases
Leptin- action
-May shed light on obesity
-Mice with a particular genetic defect (defective Ob gene) are unable to produce leptin and overeat
-Injections of leptin reduced food intake in mice however such techniques have failed in obese humans
Steroid hormones
Corticoids
Glucocorticoids- principally cortisol, released by the adrenal gland in response to stress
Mineralocorticoids- also produced by the adrenal glands and reduced salt secretion in the kidneys
Sex steroids
Androgens- eg testosterone masculinising and de-feminising effects
Estrogen- feminising effects
Progesterone- pre[ares uterus for implantation,regulates the stages of pregnancy
Testosterone in action
-Produced in the testes
-Sculpts the mail body
-Maintains male secondary sexual characteristics
-Promotes courtship,dominance and sexual behaviour
-Thought to be responsible for sex differences in behaviour and cognition
Estrogen in action
-Released by ovaries
-Promotes female secondary sexual characteristics
-Involved in water retention,calcium metabolism and sexual and maternal behaviours
-Fluctuates throughout the menstrural cycle
Estrogen and sexual behaviour
Study- when hetrosexual couples initiated sex during a woman’s cycle- men consistent whereas womens initiation varies
Control of hormone release
Hormone release is controlled by two key structures
-Hypothalamus
- pituitary
Hypothalamus activated –> pituitary gland activated -> hormones secreted
Hypothalamus
-Part of the diencephalon belonging to the forebrain
-Nuclei synthesise releasing hormones that either stimulate of inhibit the release of hormones from the pituitary
Pituitary
-The master gland
-Produces at least 10 hormones which influence other endocrine glands
-2 separate regions
-Anterior
-Posterior
Anterior pituitary
TROPIC- stimulate various processes
Luteinizing Hormone (LH) increases production of progesterone and stimulates ovulation in females. In males it increases production of testosterone
Thyroid- stimulating Hormone (TSH)-controla secretions of the thyroid gland
Prolactin- controls milk production in females
Anterior pituitary
-Growth hormone (GH)- increases body growth
-Andenocorticortopic hormone (ACTH)- controls secretions of the adrenal gland
Follicle-stmulating hormone (FSH)- increases production of estrogen and maturation of the ovum (in females) and sperm production in males.
Posterior pituitary
Stores oxytocin- controls uterine contractions,milk release, parental behaviour and orgasm
Stores Vasopressin (anti-diuretic hormone ) - constricts blood vessels, raises blood pressure, decreases urine volume
Mechanisms of hormone release
1- stimulus from sensory neurons
-Sensory information from parts of the boy travel to the hypothalamus
Triggers secretion of hormones
Duration- 2-3 secs
Child breast feeding -> sensory stimulus from breast to hypothalamus->pituitary secretes the hormone oxytocin -> oxytocin stimulates milk production
mechanisms of hormone release (2)
- Feedback
Hypothalamus monitors hormone levels in the blood
Inhibits or secretes hormones as appropriate
Hypothalamus detects low levels of thyroid hormone in the blood -> hypothalamus secrets thyroids stimulating Hormone- releasing hormone (TSH-RH)-> Pituitary secretes thyroid-stimulating hormone-> thyroid hormone levels increace
Hormone behaviour relationships
-Do not cause a particular behaviour rather, they change the likelihood that a particular behaviour will occur in an appropriate environmental context
-Certain behaviours can also influence hormone levels
- chicken and egg problem- do hormones influence behaviour by directly affecting the brain, or does behaving in a particular manner influence hormone production?
Hormone behaviour relationships
1- remove the source of a hormone the a behaviour thought to depend on that hormone should dissappear
2- Once behaviour has ceased following removal, restore hormone function and see if the behaviour returns
3- if hormone and certain behaviours are related then alterations in the relative concentration of a hormone should produce related alterations in behaviour
Human hormone disorders
Congenital adrenal hyperplasia (CAH)
-foetus exposed to excessive amounts of androgen
Affected females-masculinied genitals and behaviour. Affected male- prescouis puberty
Human hormone disorders
Congenital adrenal hyperplasia (CAH)
-foetus exposed to excessive amounts of androgen
Affected females-masculinied genitals and behaviour. Affected male- prescouis puberty
Human hormone disorder
Complete Androgen insensitivity syndrome (AIS)
-male brain an body unresponsive to androgens
- feminised due to estrogen
-typically reared as girls
Human hormone disorder
Complete Androgen insensitivity syndrome (AIS)
-male brain an body unresponsive to androgens
- feminised due to estrogen
-typically reared as girls
