Biopsychology Flashcards
Commissurotimy (Sperry 1968)
- The corpus callosum connects the two hemispheres of the brain. The procedure would cut through the 2 hemispheres (controls epilepsy)
- Due to the communication line being broken, sperry was able to see the extent to which hemispheres worked independently from each other
Left and right hemispheres
L: More geared towards analytic and verbal tasks
R: More adept at performing spatial tasks and music
- right can only produce rudimentary words and phrases but contributes emotional and holistic content to language
Evaluation of Sperry
+ experiments used highly specialised and standardised procedures
+ method was ingenious, image would be projected for 1/10th of second so that ppts wouldn’t have time to move eyes across both sides of visual field and both sides of the brain
- Puncetti (1977) suggested the hemispheres are so different it is like having 2 minds whereas other researchers believe the 2 hemispheres form a highly integrated system involved in most everyday tasks
- sample was unusual as 11 ppts who all had variations of the basic procedure and had a history of epileptic seizures took part. This means that the findings may be person specific.
- differences in function may be overstated as each hemisphere can do tasks typically associated with the other hemisphere
Core body temp (highs and lows)
Lowest approx 4am
Peak approx 6pm
Folkard (1985)
- Isolated 12 ppts from natural light for 3 weeks, manipulating clocks so that only 22 hours passed in a day.
- one of the participants could adjust comfortably to the pace of the clock, showing the strength of the circadian rhythm and extent to which it can be overridden
- also found primary school children had better recall in afternoon (Gupta found afternoon iq tests were higher on average
Infradian rhythms
- A type of biological rhythm with a frequency of less than one cycle in 24 hours e.g. menstrual cycle
- a type of biological rhythm with a frequency of more than one cycle in 24 hours. Rest + activity cycle
Exogenous
Growing or originating from outside the body
Endogenous
Growing or originating from inside the body
Eastman (SAD study)
- randomly assigned 96 patients one of three bright light treatments, either 1.5 hours in the morning, evening, or palcebo
- found that all showed remision of symptoms but morning then eve then placebo in order (placebo 30%)
Stages of sleep
1 and 2: person may be woken from light sleep
3 and 4: delta waves are slower meaning a deep sleep
5: body is paralysed but brain activity speeds up to resemble awake brain. Dreaming.
- sleep cycle follows an ultradian rhythm of 90 mins
- Kleitman (1969) suggested we move in 90 min needs for rest, fatigue, etc throughout the day
Evolution of the menstrual cycle
- women’s periods are often synced so more mothers would have babies at the same time so they could help each other
- however a woman’s lifestyle, diet, etc. have an effect on the cycle so McClintlocks study would be down to chance
Endogenous pacemakers
Referred to as internal biological clocks e.g. suprachiasmatic nucleus (SCN)
Exogenous zeitgebers
Reset this clock everyday to maintain coordination with the external world
Animal studies
- Decoursey (2000) captured 30 chipmunks and destroyed SCN connections in the brain meaning they had no awareness of sleep wake cycle
- Ralph (1990) bred hamsters with 20 hour sleep wake cycle, heavily effecting the hamsters
- ethical issues as many could not function properly or were killed by predators
Pineal gland
Increases production of melatonin at night as it induces sleep and is inhibited during periods of wakefulness
Burgess (2003)
Exposure to bright light prior to east-west flight decreased rime needed to readjust. Decreased jet lag
Evaluation of endogenous …
+ Burgess (2003) Exposure to bright light prior to east-west flight decreased rime needed to readjust. Decreased jet lag
+ babies circadian rhythm after 6 weeks as parents impose a schedule which has a large influence on meal and bed tiene
- rest of body can function and respond to circadian rhythms without SCN
- Campbell and Murphy (1998) shone light onto the back of the legs of 15 ppts and effected sleep by up to 3 hrs showing the effect of light
- mikes (1997) accounted the life of a blind man who despite social cues couldn’t change his 24.9 hr sleep wake cycle
The brain
Ensures life is maintained Many parts of the brain, concerned with vital functioning like problem solving and thinking
The spinal chord
Facilitates the transferral of messages to and from the brain to the PNS. Also involved in reflex actions
The peripheral nervous system (PNS)
Transmits messages via millions of neurons, to and from the CNS The PNS is divided into the somatic NS and the autonomic NS
The somatic nervous system (SNS)
This is the part of the PNS that is responsible for carrying sensory and motor inform to and from the spinal chord
The autonomic nervous system (ANS)
This governs vital functions in the body such as breathing, heart rare, digestion, sexual arousal and stress responses (fight or flight]
Endocrine system
One of the body’s major information systems that instructs glands to release hormones directly into the bloodstream
Hormones
Chemical substances that circulate in the bloodstream, their effects on behaviour can be very powerful