Biopsychology Flashcards
Fight or flight definition -
Sequence of events that occur in the body which occur due to the body needing to defend itself by attacking (fight) or flee situation (flight).
What are involved in the fight or flight -
Amygdala, pituitary gland and the hypothalamus.
Amygdala and hypothalamus coordination -
When there is a perceived threat the amygdala is stimulated
Sends distress signal to the hypothalamus communicates with the rest of the body though the sympathetic NS. (Prepares the body)
Acute (sudden stressors) - SNS
Begins preparing the body for rapid action of fight or flight, SNS sends a signal through to the adrenal medulla which responds by releasing adrenaline into the bloodstream. The SNS is connected via the hypothalamus.
Adrenaline in acute stressors
Comes from the adrenal medulla
Also releases noradrenaline
Adrenaline results in a number of psychological changes by pushing blood to working muscles, triggers the releases of glucose increases blood pressure.
The PNS in the acute stressors -
When the threat has passed the PNS is activated and results in a dampened down response reducing the effects of heartbeat and blood pressure and results in glucose being stored. (Rest and digest)
Chronic stressors -
HPA axis where the brain continues to perceive something as a threat
HPA axis is what -
Secondary system kicks in, the hypothalamus activates a stress response system called the HPA axis.
The HPA axis -
Order of events
H - Hypothalamus - relies on hormonal signals to keep the SNS working, in response to a continued threat releases CRH in response to the stressor.
P - The CRH arrives at the pituitary gland to release ACTH where it is transported down to the target site of the adrenal glands.
A - ACTH stimulates the release of stress related hormones such as cortisol which allow some sudden changes in the body suitable for fight or flight of quick bursts of energy and a lower sensitivity to pain.
Motor cortex -
Located in the Frontal lobe generated voluntary motor movements, both hemispheres have a motor cortex and controls muscle on the opposite side of the brain.
Somatosensory cortex -
Located in the Parietal lobe and is involved in the processing of different sensory events rising from different parts of the body produces sensations of touch, pressure, pain and temperature which is then localised to different areas of the body.
Broca’s area -
Language centre in the frontal lobe and is related to speech production. Broca found this evidence from studied patients.
Wernicke’s area -
Area in the temporal lobe which is used in the understanding of language. Shortly discovered after the discovery of the Broca area.
Circadian rhythm -
A pattern of behaviour that occurs or reoccurs every 24 hours like the sleep-wake cycle. Biological rhythms.
Sleep-wake cycle -
- Dictates when we should be asleep and awake.
- Light and dark are external signals that when we need to sleep and are awake.
- Synchronised by the master circadian pacemaker the suprachiasmatic nucleus. (hypothalamus)
- Light provides the primary input to this system which set the body clock and act as photoentrainment.
- These light stimuli are sensitive within the eye and act as brightness detectors send messages to the SCN which coordinate the activity of the entire circadian rhythm.
Other circadian rhythms -
Hormonal and temp:
Temp - lowest about 4.30am and highest about 6pm, sleep begins to occur roughly during the hours when temperature is lower and alertness is stimulated when the temperature is raised. Happens over a 24 hour cycle
Hormones - melatonin from the pineal gland in the brain is a result of circadian rhythms with peak levels occurring around darkness when its light again melatonin production is reduced so when waking.
Ultradian rhythms - Sleep cycle
Sleep stages - results in humans following sleep patterns consisting of REM and NREM, repeats every 90-100 minutes through the night starts with NREM and then ends with REM over the cycle. Most of what we understand from these cycles comes from the electrical activities of the brain recorded with each showing a distinct of EEG for example they enter the stages there heart rate slows and breathing pattern slows. Kleitman referred to the 90 minute cycle found during sleep as the BRAC cycle however it is said to even continue during the day. (Human mind focuses for 90 minutes during the day but towards the end we begin to get tired and hungry and move from the state of alertness to a state of fatigue.
Infradian rhythms - Menstrual cycle (Monthly)
Menstrual cycle lasts for one month there are variations with this cycle (shortest at 23 and the longest at 36), regulated hormones which either promote ovulation or stimulate the uterus for fertilisation.
Weekly and yearly cycle
Weekly - Testosterone levels begin to increase at the end of the week and young couples report more sexual activities at the weekends. These levels begin to deplete during weekdays.
Yearly - Individuals respond to the changes of seasons and temperatures resulting in variations of moods. There are more suicides in the winter months than the summer ones.
Endogenous pacemakers -
Mechanism within the body that regulate the internal biological bodily rhythms.
SCN -
In mammals the SCN is made up of a tiny cluster of nerve cells in the hypothalamus, it regulates the biological bodily rhythm, master clock which links to other brain regions controlling sleep and arousal. It receives information about light levels from the optic nerve. It sends information to the pineal gland where it regulates the production of melatonin at night and decreases during the morning. The pineal and SCN join together to become endogenous pacemakers of the brain.
Exogenous zeitgebers -
Environmental cue such as light which helps regulate the biological clock in an organism. Light and social cues.
Light as an exogenous zeitgeber -
Receptors in the SCN are sensitive to changes of light during the day and night and use the info to regulate activity of the body’s organs and glands, light resets the internal bodily clock each day keeping it on a 24 hour cycle.
Social cues can act as zeitgebers too -
Like meal times and social activities, This was found on one of the earliest studies on jet lag - where circadian rhythms of air travellers responded more quickly if they were exposed to social cues of their new time zones and this acted as a zeitgeber. This supports Aschoffs idea that people are able to compensate for the absence of such zeitgebers such as natural light responding to social zeitgebers too.
Post mortem examinations -
Examine the brains of people of shown psychological abnormalities prior to their death, exploring this allows them to establish their underlying neurobiological cause of their behaviour of when they were alive. These have helped to understand how some disorders have come about.
fMRI -
Measures brain activity, it detects the changes of the amount of oxygenated blood flow to areas of the brain. This allows maps of the brain to be made in order to understand the relevance of what distinct areas are experiencing neural activity.
EEG -
Records measures of different electrical changes of the brain using electrodes attached to a scalp. Can be used to detect various types of brain disorders and there are 4 basic EEG patterns.
Event-related potentials -
Uses raw EEG data and takes it into investigate cognitive processing of specific events, these are small voltage channels in the brain that are triggered by specific events or stimuli, such as cognitive processing.
Functional recovery -
refers to the recovery of abilities and mental processes that have been compromised as a result of brain injury or disease.
Brain plasticity -
Refers to the brains ability to modify its own structure and function as a result of experience.
Human studies of plasticity of Maguire Taxi study -
Using an MRI, the posterior hippocampi was significantly larger than the control group may be due to spatial navigation.
Stem cells can be used in the effects of functional recovery -
Stem cells are unspecialised cells which have the potential to form different cell types that can carry out any function. Including nerve cells. Stem cells can provide a number of different treatments, for example if they were directly placed in the brain then they may replace dying nerve cells.
Neuronal unmasking -
Wall first identified dormant synapses which exist anatomically but their function is blocked, increasing the rate of inputs to these synapses can open these dormant synapses by gaining potential enough of an action potential which allow regions of the brain to open that are not normally active.
Sperry and Gazaniga research -
- First to study spilt brain research
- Test the idea that some mental processes are suited to the one of the two hemispheres.
- Corpus callosum is cut in these patients so these mental processes could not be coordinated between adjacent hemispheres.
- The information is presented to only one hemisphere
- PP would fixate on a dot where info would either be presented to the right or left visual field and then make responses to their left or right hand (controlled by the opposite hemisphere)
- IMPORTANT - left hemisphere dominant for language and right is dominant for visual-motor tasks
If patient was flashed with a dog in the left visual field it travels to the right hemisphere but as there is no corpus callosum they would say they see nothing as there is no language centre it cannot respond verbally, but if it was flashed to the right hemisphere they could say what was seen but as it needs to be processed through a visual field of the right hemisphere they cannot say it.
