Biopsychology

• The nervous system is composed of the brain and the spinal cord, and the peripheral nervous system (PNS) relays messages from the environment to the central nervous system (CNS), via sensory neurons, and from the CNS to effectors, via motor neurons.
• The PNS is further subdivided into the autonomic nervous system (ANS) which controls involuntary, vital functions of the body, such as maintaining heart rates and breathing rates, and the somatic nervous system (SNS) which receives information from sensory receptors belonging to each of the 5 senses, and results in effectors being stimulated by the CNS, via motor neurons.
• The autonomic nervous system is also subdivided into the sympathetic and parasympathetic branches.
• The sympathetic nervous system increases heart rates, breathing rate, causes vasoconstriction and pupil dilation, while the parasympathetic nervous system decreases heart rate, breathing rates, causes vasodilation and pupil constriction.
• The endocrine system is the main chemical messenger system of the body, where hormones are secreted into the bloodstream from glands, and then are transported towards target cells in the blood, with complementary receptors.
• The pituitary gland is considered to be the ‘master’ gland because it controls the release of hormones from all other glands in the body.
• The thyroid releases the hormone thyroxine, which increases heart rate and therefore increases the rate of growth.
• The adrenal gland releases adrenaline which creates the physiological arousal preceding the fight or flight response, through increasing the activity within the sympathetic branch of the autonomic nervous system.
• The fight or flight response is described as follows: 1.The body senses and becomes aware of a stressor in the environment, such as the sound of a speeding car, through sensory receptors and sensory neurons in the peripheral nervous system.
• There are considerable ethical issues with the use of animals in biopsychology research, particularly if they are deliberately put in harm's way, as was the case with Decoursey et al, which breaches the BPS ethical guideline of protection from psychological and physical harm.
• Lieperta et al (1998) found that after constraint-induced movement therapy, the motor performance of stroke patients improved significantly.
• The influence of exogenous and endogenous factors may be overestimated.
• Research suggests that an increased cognitive reserve increases the likelihood of making a disability-free recovery (DFR) after trauma, due to increased rates of neuroplasticity.
• A cost-benefit analysis would need to be conducted to assess whether the ethical costs of using animals in biopsychology research outweigh the benefits of an improved understanding of exogenous zeitgebers and endogenous pacemakers.
• Through sensory receptors and sensory neurons in the peripheral nervous system, information about the stressor is sent to the hypothalamus in the brain which coordinates a response and triggers increased levels of activity in the sympathetic branch of the autonomic nervous system.
• Positive plasticity has been demonstrated by the case study of Jodi Miller, who has shown the power of recruiting homologous areas on the opposite side of the brain, axonal sprouting and the reformation of blood vessels.
• There have been recorded cases where exogenous zeitgebers and endogenous pacemakers have failed to entrain or alter circadian rhythms, as demonstrated by Miles et al (1977) who reported the case of a man with a sleep-wake cycle of 24.9 hours, which could not be changed through the use of either stimulants or sedatives.
• The researchers found that, although the right eye was closed, there was still activity in the left visual cortex, corresponding to the development of occular dominance columns.
• There are limitations in generalising findings from animal studies to humans, particularly due to differences in physiology and the number/types of circadian rhythms, which limits the ecological validity of such findings.
• Ramachandran has demonstrated negative plasticity through providing an explanation for phantom limb syndrome in terms of cortical reorganization in the cortex and thalamus (particularly, the somatosensory area).
• Schneider et al (2014) found that of the 769 patients studied, 214 achieved DFR after 1 year.
• Cognitive reserve is the level of education a person has attained and how long they have been in education.
• Ramachandran’s research into phantom limb syndrome explains it as being caused by the sensory input from the face skin ‘invading’ and activating deafferented hand zones in the cortex and thalamus.
• Of those, 50.7% had between 12 and 15 years of previous education and 25.2% had more than 16 years.
• Functional recovery cannot be relied upon to reinstate normal function.
• Hubel and Weisel (1970) sutured the right eye of kittens, who are blind from birth, for a period of 6 months, opening the eyes and several points and monitoring brain activity in the visual cortex.
• Function is not always lateralised to specific hemispheres.
• There is evidence supporting not only the existence of, but also the uses of plasticity.
• Adrenaline is released from the adrenal medulla in the adrenal glands, and is transported to target effectors, via the blood and through the action of the endocrine system.
• This results in the rectum contracting, saliva production being inhibited and a greater breathing rate, creating the physiological response needed to sustain the fight or flight response, whose adaptive purpose is to enable us to escape the stressor and so increase the likelihood of our survival.
• Once the stressor is no longer a threat, as part of an antagonistic pairing, the hypothalamus triggers less activity in the sympathetic branch and more activity in the parasympathetic branch of the autonomic nervous system, also referred to as the rest and digest response, due to the parasympathetic branch decreasing the activity which was originally increased through the action of the sympathetic branch.
• Synaptic transmission is a method of neurons communicating with each other, relaying information to the central nervous system across sensory neurons and carrying out responses dictated by the brain through sending information to effectors via motor neurons.
• The process of synaptic transmission involves an action potential arriving at the presynaptic membrane, causing depolarisation through the opening of voltage-dependent calcium ion channels, and the consequent influx of calcium ions.
• Petersen et al (1988) found that Wernicke’s area activation is required for listening tasks, whereas Broca’s area is required for reading tasks, confirming the idea that Wernicke’s area is involved in speech comprehension, whilst Wernicke’s area is responsible for language production.
• The auditory area, located in the temporal lobe on the superior temporal gyrus, is responsible for processing auditory information and speech.
• Broca’s Area, located in the frontal lobe, is responsible for speech production and is usually found in the left hemisphere.
• The motor area, located in the frontal lobe and separated from the auditory area by the central sulcus, is involved in regulating and coordinating movements.
• Excitatory neurotransmitters like dopamine increase the potential difference across the postsynaptic membrane through triggering the opening of more voltage-dependent sodium ion channels, increasing the likelihood that an action potential will be generated.
• Lesions or damage in the motor area result in an inability to control voluntary fine motor movements.
• Serotonin reduces the potential difference across the postsynaptic membrane through the closure of the voltage-dependent sodium ion channels, reducing the likelihood that an action potential will be generated.