Biopsychology Flashcards

Question

if inhibitory are more active then...

Answer 1

they fire at a slower rate

Answer 2

- Produce and secrete hormones - Majority include the pituitary gland, adrenal glands and reproductive organs - Each gland produces different hormones - Regulated by feedback, signal sent to hypothalamus who sends to endocrine who sends hormones to target organ which then causes change, change sensed by hypothalamus which shuts down secretion of hormones and slows down secretion of target organ hormones

Answer 3

- Chemicals that circulate in the blood stream and carried to target sites - They usually only affect a given number of target cells as they have receptors that are specific to that hormone - When enough receptor sites are stimulated by hormones this results in physiological reaction in the target cell - Timing of hormone release is critical for normal functioning as too little or too much released at the wrong time could lead to dysfunction

Answer 4

- Releases hormones who influence the release of hormones from other glands regulating many of the body functions - Controlled by the hypothalamus, this receives information from many sources about the basic functions of the body and then regulates these functions - Produces hormones which travel in the bloodstream and directly causes changes in physiological processes in the body or stimulate other glands to produce other hormones - High levels of hormones in other endocrine glands can stop the hypothalamus and pituitary gland releasing more of their own hormones this is called negative feedback

Answer 5

- the anterior pituitary and posterior pituitary

Answer 6

releases ACTH to respond to stress, it stimulates the adrenal glands to produce cortisol, the anterior also produces LH and FSH which is important in reproductive functioning, stimulate the ovaries to produce oestrogen and progesterone and in males that stimulate the testes to produce testosterone and sperm

Answer 7

- Posterior releases oxytocin which stimulates the contraction of the uterus during childbirth and is important in mother infant bonding

Answer 8

- Two adrenal glands sit on top of the kidneys, made up of two parts, the outer part is called the adrenal cortex and the inner is known as the adrenal medulla - Different in functions, hormones released by the cortex are essential for life whereas those released by the medulla are not

Answer 9

produces cortisol which supports bodily functions, increased in response to stress, If cortisol is low then individual has low blood pressure and poor immune function and cannot deal with stress, It produces aldosterone which maintains blood volume and blood pressure

Answer 10

releases adrenaline and noradrenaline that prepare the body for fight or flight, helps respond to stressful situations

Answer 11

The amygdala and hypothalamus - When individual is faced with a threat the amygdala responds, this associates sensory signals with emotions such as fear and anger - Then sends a distress signal to the hypothalamus which communicates with the rest of the body - Bodies response to stressors are two options – acute stressors such as personal attack, the second is chronic stressors such as a stressful job Response to acute sudden stressors The sympathetic nervous system - It begins to prepare the body for rapid action necessary for fight or flight - Sends a signal to the adrenal medulla which increases the hormone adrenaline Adrenaline - Goes through the body and causes physiological changes, causes heart beat to increase, and blood pressure to increase - Breathing becomes more rapid and is deeper to increase the amount of oxygen - Amount of energy increases in the body so it can reply to the fight or flight The parasympathetic nervous system - When the threat has past the parasympathetic branch of the ANS decreases the stress responses - Causes the heartbeat and blood pressure to drop again - Digestion happens again Response to chronic stressors - If the brain continually sees something as threatening then it uses a second system, this causes the adrenaline to decrease and the hypothalamus activates a stress response system called the HPA axis which consists of the pituitary gland and the adrenal gland - H – this is the hypothalamus, relies on a series of hormonal signals to keep the SNS working and it releases a series of chemical messengers CRH which is released into the blood stream in response to a stressor - P – this is the pituitary gland, when CRH arrives at the pituitary gland is causes it to produce and to release ACTH which is transported in the bloodstream to the adrenal glands - A – the adrenal glands, the ACTH causes the adrenal cortex to release various stress related hormones including cortisol, which is responsible for some of the fight or flight responses, they can be positive meaning that it causes an increase in energy and a decrease in pain or negative as it causes impaired cognitive performance and a lowered immune system - Feedback – this is efficient at regulating itself as both hypothalamus and pituitary glands have special receptors that monitor cortisol levels if they rise above normal then they initiate a reduction in CRH and ACTH levels

Answer 12

Motor and somatosensory areas The motor cortex - Responsible for voluntary movement - Located in the frontal lobe along the precentral gyrus - Both hemispheres have a motor cortex and they control opposite sides of the body, they are arranged next to each other The somatosensory cortex - Detects sensory events arising from different regions in the brain - Located in the parietal lobe of the brain along the postcentral gyrus, this is the area of the cortex which processes sensory information in regards to touch, it localises this area - In both hemispheres receiving information from opposite sides of the body Visual and auditory centres Visual centres - Located in the visual cortex in the occipital lobe of the brain - Visual processing begins in the retina where light enters and strikes the photoreceptors, nerve impulses from the retina are then transmitted to the brain via the optic nerves - Some nerve impulses from the retina travel to areas of the brain involved in coordination of the circadian rhythms but the majority end in the thalamus which acts as a relay station and passes information into the visual cortex - Spans both areas of the hemisphere, right hemisphere receive input from the left hand side whiles the left receives input from the right - Visual cortex has several different areas which process different types of visual information Auditory centres - Lies within the temporal lobes on both sides of the brain - Begin in the cochlea in the inner ear this is where sound waves are converted to nerve impulses which travel via the auditory nerves to the auditory cortex in the brain - First stops at the brainstem this is where the decoding takes place then next is the thalamus which acts as a relay station and also processes the information, last stop is the auditory cortex acts as a response Language centres Broca’s area - Named after a French neurosurgeon who treated a patient who he referred to as tan as this was the only syllable that the patient could say - Tan was able to understand language but not able to speak it, therefore Broca studied 8 other patients who had similar deficits along with lesions in their left frontal hemisphere, patients with damage to the right area did not have the same language problems therefore he identified a language centre in the frontal lobe in the left hemisphere which is critical for speech - Other neuroscientists have found evidence of activity in the area when people perform cognitive tasks which have nothing to do with speech - Fedorenko et al, discovered two regions of Brocas area one involved in language and the other to do with cognitive tasks Wernicke’s area - Discovered an area of the brain that was involved in understanding language, this was in the left temporal lobe - Patients could speak but not understand language - Therefore he proposed that language involves separate motor and sensory regions which are located in different cortical regions - The motor region is near the area which controls the mouth therefore it control the mouth and tongue - Sensory region is close to the regions that are responsible for auditory and visual input - Neural loop that runs between Brocas and Wernickes area

Answer 13

Hemispheric Lateralisation - Laternalisation refers to the two halves of the brain being not alike - Each hemisphere is different, for example neural mechanisms for some functions of the brain such as language is primarily in one half of the brain. Broca established that damage in a particular area of the left brain hemisphere led to speech deficits whereas damage to the right hemisphere in the same place did not have the same effect - Important question is if that language is in the left hemisphere then how can we talk about things in the right hemisphere, thereof ore the two hemispheres are connected this allows connection through a bundle of nerve fibres such as the corpus callosum - In treatment for serve epilepsy surgeons cut the bundle of nerves that formed the corpus callosum this was done to prevent the violent electrical activity that accompanies electrical seizures this split their brain Split brain research Sperry and Gazzaniga’s research - Sperry and Gazzaniga studied split brain patients, to test separated hemispheres they were able to send visual information to one hemisphere at a time in order to study hemispheric lateralisation - As there was no corpus callosum the information can only be processed in the hemisphere that it is received in, in a typical study the split brain patient would focus on a dot in the centre of the screen while information was presented to either the left or right visual field, they were then asked to make responses with their left or right hand which is controlled by opposite hemispheres or verbally which is controlled by the left hemisphere without seeing what their hands were doing - For example if the patient was flashed a picture of a dog on their right visual field they were asked what they were seen and they would reply dog but if they saw this on the left visual field then they would say that they see nothing as the information from the left visual field is processed by the right hemisphere which can see the picture but it has no language centre so cannot reply verbally What have we learnt from split brain research - Working with split brain patients have discovered a number of differences between the two hemispheres - Left is responsible for speech and language - And the right specialises in visual-spatial processing and facial recognition - Split brain has not shown that the brain is organised into specific regions for specific tasks instead it suggests a connectivity between different regions

Answer 14

Neural organisation is changed as a result of experience, there are many types of experience that can do this Plasticity as a result of life experience - As people gain life experiences nerve pathways are used to develop stronger connections whereas neurons that are not used die out - Therefore the brain can adapt to situations and changing environments - Natural decline in cognitive functioning with age can be attributed to changes in the brain and this had led to evidence to look for ways in which new connections can be made to reverse this effect - For example Boyke et al – found evidence of brain plasticity in 60 years old taught a new skill and this caused increases in grey matter in the visual cortex when the practising stopped changes are reversed Playing video games - Kuhn et al – they compared a control group with a video game training group that was trained for two months for at least 30 minutes a day on the game super Mario. They found increase in grey matter in various brain areas including the cortex hippocampus and cerebellum this is not evident in the control group who did not play the video game - Caused new synaptic connections in brain areas involved in spatial navigation, planning, working memory and motor performance Meditation - Researchers working in Tibetan monks have been able to demonstrate that meditation changes the inner workings of the brain. - Davidson et al – compared 8 monks who meditated with 10 volunteers who had no meditation experience, they were fitted with electrical wires and asked to meditate, electrodes picked up greater activity of gamma waves in the monks while the students only had a shorter increase of gamma waves - Therefore meditation changes the workings of the brain in the short term and permeant as the monks had more gamma rays then before they started to meditate Functional recovery after trauma Using stroke patients it was found that the brain could re wire itself over time so that some level of function can be regained, although some parts are damages others take over the functions that were lost, neurons can make new circuits Mechanisms for recovery - Regenerative developments in brain functions arise from brains plasticity this is the ability to change structurally and functionally after trauma, it does this in two ways this is neuronal unmasking and stem cells - Neuronal unmasking – Wall 1997, this identified dormant synapses in the brain, they exist anatomically but their function is blocked, as the rate of neural input is too low for them to be activated but increasing the rate of activity can cause them to work again and open connections this creates a spread of activation which leads to the development of new structures - Stem cells – unspecalised cells that can differentiated and specialise they can become nerve cells therefore replacing damaged cells or neurodegenerative disorders, can be placed in the brain or transplanted that could rescue injured cells or they could form a new neural network

Answer 15

Post – mortem examinations - Used to establish the underlying neurobiology of a particular behaviour - May study behaviour while they are alive that suggest possible underlying brain damage, they can look for abnormalities which explain their behaviour - Used for Brocas Tan to prove the brocas area - Made it possible to identify parts of the brain that are to do with memory for example HM – his inability to memorise was shown by lesions in the hippocampus Scanning techniques Functional magnetic resonance imaging (fMRI) - This measures changes in brain activity whole a person performs a task, measures change in blood flow in particular areas of the brain which indicates increased neural acitivity in that area, when brain activity increases in a particular area then the amount of oxygen supplied to that area increases and the change in blood flow is what the researchers measure - Can be used to see a matching pattern of change and therefore results can be concluded Electroencephalogram (EEG) - Measures electrical activity in the brain as electrodes detect small electrical charges in the brain and this is recorded on a EEG - This can be used to detect various types of brain disorder or diagnose other disorders that influence such as Alzheimer’s - Four basic EEG patterns are alpaha waves, beta waves, delta waves and theta waves, when a person is awake but relaxed the alpha waves are recoreded when they are physiologically aroused their EEG patterns show a low amplitude and fast frequency beta waves, they are also found in REM sleep when eyes move back and forth, delta and theta occur when the person is asleep Event – related potentials (ERPs) - Small voltage changes in the brain that are triggered by specific events or stimuli, difficult to pick out from all the other electrical acitivity being generated at once - Many presentations of the stimulus have to happen to established one particular average, has to cancel out background noise - Can be divided into two categories – waves within the first 100 milliseconds are sensory ERPs as they reflect initial responses and those after the first 100 reflect how the individual evaluates the stimulus

Answer 16

The nature of circadian rhythms - Circadian rhythms are driven by our body clocks and are found in all cells of the body they are synchronised by the master circadian pacemaker – the suprachiasmatic nuclei which is found in the hypothalamus - Pacemaker is constantly reset so that our bodies are in synchrony with the outside world - Light is the primary input to the system, setting the body clock to the correct time is a process termed photoentrainment - In mammals light sensitive cells within the eye act as brightness detectors and send messages to the SCN about the light levels, the SCN then use this information to coordinate the activity of the entire circadian system The sleep wake cycle - The circadian rhythm not only dictates when we should be sleeping but when we should be awake, light and darkness are the external signals that determine when we need to sleep and when we need to wake up - Dips and rises happen at different times of the day, they usually occur between 2-4am and 1-3 pm this is where we feel more sleepy this is less intense if we have had sufficient sleep - Sleep and wakefulness is also determined by the homeostatic control, when we are awake for a long time then it tells us that we need more sleep due to the energy used in wakefulness, gradually decreases during the day and then in late evening when most people fall asleep - The circadian system keeps us awake as long as its daylight, promoting us to sleep as it becomes dark, the homeostatic system tends to make us sleepier as time goes on throughout the waking period regardless of night or day - The internal circadian system keeps us awake and maintains a clock for about 24-25 hours a day even in the absence of external cues - Major alternations in sleep and wake schedules because this causes the biological clock to become out of balance Other circadian rhythms - Core body temperature – best indications of the circadian rhythm, it is at its lowest at 36 degrees which is at 4:30am and at its highest 38 degrees which is at 6:00 pm, sleep occurs when the core body temperature drops and the body temperature rises in the last hours of sleep this promotes the feeling of alertness - Hormone production – hormone release follows a circadian rhythm for example the production and release of melatonin from the pineal gland in the brain and follows a circadian rhythm, peak levels occur in the dark and by activating chemical receptors in the brain it encourages feelings of sleep

Answer 17

Ultradian rhythms - The sleep portion of this cycle follows a type of rhythm called an ultradian rhythm, this is a biological rhythm that is referred to as ultradian as it lasts less than 24 hours Sleep stages - Ulradian rhythm found in human sleep follows a pattern of alternating REM (rapid eye movement) and NREM (non rapid eye movement) this consists one through 4 stages - Cycle repeats itself every 90-100 minutes with stages having different duratiosn - Cycle consists of a progression through the 4 stages of NREM sleep before entering a final stage of REM sleep then the whole cycle starts again - Stage 1- 4-5%, this is light sleep, muscle activity slow down, occasional muscle twitching - Stage 2 – 45-55% breathing pattern and heart rate slows, slight decrease in body temperature - Stage 3- 4-6% deep sleep begins, brain begins to generate slow delta waves - Stage 4-12-15% very deep sleep rhythmic breathing, limited muscle acitivty and brain produces delta waves - Stage 5 – 20-25% - rapid eye movement, brainwaves speed up and dreaming occurs, msucles relax and heart rate increases, breathing is rapid and shallow The basic rest activity cycle - Kleitman 1969 – referred to the 90 minute cycle found during sleep as the best rest acitivty cycle (BRAC), but he suggested that the 90 minutes occur during the day, but rather than moving through sleep stages we move progressively from a state of alertness into a state of sleep stages - Human can focus for 90 minutes and towards the end they loos concentration, fatigue and hunger Infradian rhythms - Rhythms that are longer than 24 hours, they may last days, weeks months or even may be annual - Like the female menstrual cycle in humans Weekly rhythms - Lots of weekly rhythms confined to 7 days a week for example male testosterone levels increase at the weekends as they are more likely to have sex than during the weekdays, frequency of births on weekends is lower than on weekdays - Halberg et al – reported 7 day rhythms of blood pressure and heart rate but evidence is weak Monthly rhythms – human menstrual cycle - Women’s reproductive cycle lasts about 1 month and is regulated by hormones which either promote ovulation or stimulate the uterus for fertilisation - Ovulation occurs halfway through when the oestrogen level peaks and lasts for 16 to 32 hours, after the ovulatory phase progesterone levels increase in preparation for the possible implantation of an embryo in the uterus Annual rhythms - Annual rhythms are related to the seasons for example migration - Research suggests a seasonal variation in mood in humans some people become depressed in the winter and this is also associated with an increase in heart attacks which varies seasonally and peaks in the winter, most deaths occur in January

Answer 18

Endogenous pacemakers - Refer to the organs that are within the organism - Products of inherited genetic mechanisms and allow us to keep pace with changing environment - Most important pacemaker is the superchiasmatic nucleus – SCN The superchiasmatic nucleus - SCN is main pacemakers and lies in the hypothalamus - Generates the circadian rhythm, links to other regions in the brain which control sleep - Neurons within the SCN synchronise with each other so that their target neurons in sites elsewhere in the body receive correctly time co-ordinated signals, these peripheral clocks maintain a circadian rhythm but not for long as they must be controlled by the SCN - Possible because the SCN built in circadian rhythm which only needs resetting when external light levels change, SCN receives light levels via the optic nerve, this happens when our eyes are shut as eyes penetrate the eyelids, if our biological clock is running slow then morning light automatically adjusts the clock putting it in rhythm with the world outside The pineal gland - SCN sends information to the pineal gland in order to make it increase production and secretion of the hormone melatonin at night and to decrease it as light levels increase in the morning - Pineal and SCN jointly function as endogenous pacemakers in the brain - Sensitivity to light means it must be synchronised with the light dark rhythm outside Exogenous zeitgebers - Refers to anything that are outside the organism - Environmental events that are responsible for entraining the biological clocks Light - Receptors in the SCN are sensitive to changes in light levels - Keeps body on a 24 hour clock - Retina and rods detect light in visual images - Protein called melanopsin is sensitive to natural light which is critical in this system Social cues - Aschoff et al showed that individuals are able to compensate for the absence of zeitgebers such as natural light by responding to social zeitgebers - Early stucies of jet lag found that circadian rhythms of air travellers adjusted more quickly if they went outside more at their destination as they are exposed to social cues of their new time zone - Blind peoples circadian rhythms are no different to sighted people as both groups are exposed to the same social cues as there are still connections between the eye and the SCN