BIOPSYCHOLOGY

What is the central nervous system?

The brain and spinal cord together form the CNS. The CNS acts as the control centre of the body by providing its processing, memory, and regulation systems. The CNS takes in all of the conscious and subconscious sensory information from the body’s sensory receptors to stay aware of the body’s internal and external conditions. Using this sensory information, it makes decisions about both conscious and subconscious actions to take to maintain the body’s homeostasis and ensure its survival. The CNS is also responsible for the higher functions of the nervous system such as language, creativity, expression, emotions, and personality. The brain is the seat of consciousness and determines who we are as individuals.

What is the peripheral nervous system?

The peripheral nervous system (PNS) includes all of the parts of the nervous system outside of the brain and spinal cord.

What is the somatic nervous system?

The somatic nervous system (SNS) is a division of the PNS that includes all of the voluntary efferent neurons. The SNS is the only consciously controlled part of the PNS and is responsible for stimulating skeletal muscles in the body.

What is the autonomic nervous system?

The autonomic nervous system (ANS) is a division of the PNS that includes all of the involuntary efferent neurons. The ANS controls subconscious effectors such as visceral muscle tissue, cardiac muscle tissue, and glandular tissue.

What are the 2 parts of the autonomic nervous system?

• Sympathetic

• Parasympathetic

What does the sympathetic division involve?

The sympathetic division forms the body’s “fight or flight” response to stress, danger, excitement, exercise, emotions, and embarrassment. The sympathetic division increases respiration and heart rate, releases adrenaline and other stress hormones, and decreases digestion to cope with these situations.

What does the parasymphathetic division involve?

The parasympathetic division forms the body’s “rest and digest” response when the body is relaxed, resting, or feeding. The parasympathetic works to undo the work of the sympathetic division after a stressful situation. Among other functions, the parasympathetic division works to decrease respiration and heart rate, increase digestion, and permit the elimination of wastes.

What is a neuron?

A neuron is a nerve cell that is the basic building block of the nervous system. Neurons are specialized to transmit information throughout the body. Neurons carry signals from one place to another, around the many parts of the nervous system. They connect sense receptors to the central nervous system and also connect one part of the nervous system to another, for example in the brain and spine. They also carry signals from the nervous system to effector organs, such as muscles and glands.

What does excitation mean?

When a neurotransmitter, such as adrenaline, increases the positive charge of the postsynaptic neuron. This increases the likelihood that the neuron will fire and pass on the electrical impulse.

What does inhibition mean?

When a neurotransmitter, such as serotonin, increases the negative charge of the postsynaptic neuron. This decreases the likelihood that the neuron will fire and pass on the electrical impulse.

What happens when neurons are stimulated?

They transmit an electrical impulse

What are the 3 types of neurones and their functions?

1.      Sensory neurones carry signals from receptors to the spinal cord and brain.

 

2.      Relay neurones carry messages from one part of the CNS to another.

 

3.      Motor neurones carry signals from the CNS to effectors.

What are the stages of synaptic transmission?

1.      An electrical impulse travels along an axon.

2.      This triggers the nerve-ending of a neuron to release chemical messengers called neurotransmitters.

3.      These chemicals diffuse across the synapse (the gap) and bind with receptor molecules on the membrane of the next neuron.

4.      The receptor molecules on the second neuron bind only to the specific chemicals released from the first neuron. This stimulates the second neuron to transmit the electrical impulse.

What are neurotransmitters used for?

Neurotransmitters are the brain chemicals that communicate information throughout our brain and body. The brain uses neurotransmitters to tell your heart to beat, your lungs to breathe, and your stomach to digest. 

They can also affect mood, sleep, concentration, weight, and can cause adverse symptoms when they are out of balance. Neurotransmitter levels can be depleted many ways

What are the 2 kinds of neurotransmitters?

INHIBITORY and EXCITATORY.  Excitatory neurotransmitters are not necessarily exciting – they are what stimulate the brain.  Those that calm the brain and help create balance are called inhibitory.  Inhibitory neurotransmitters balance mood and are easily depleted when the excitatory neurotransmitters are overactive.

What is the endocrine system?

The endocrine system includes all of the glands of the body and the hormones produced by those glands. The glands are controlled directly by stimulation from the nervous system as well as by chemical receptors in the blood and hormones produced by other glands. By regulating the functions of organs in the body, these glands help to maintain the body’s homeostasis. Cellular metabolism, reproduction, sugar and mineral homeostasis, heart rate, and digestion are among the many processes regulated by the actions of hormones.

What are the differences/similarities of the endocrine and nervous system?

The endocrine system works alongside of the nervous system to form the control systems of the body. The nervous system provides a very fast and narrowly targeted system to turn on specific glands and muscles throughout the body. The endocrine system, on the other hand, is much slower acting, but has very widespread, long lasting, and powerful effects. Hormones are distributed by glands through the bloodstream to the entire body, affecting any cell with a receptor for a particular hormone. Most hormones affect cells in several organs or throughout the entire body, leading to many diverse and powerful responses. 

When was the Phineas Gage case study?

1848

Summarise what happened to Phineas Gage:

In 1848 Gage was working as a foreman on the construction of the Rutland and Burlington Railroad in Vermont, USA. Workers often used dynamite to blast away rock and clear a path for the railway. On 13 September, Gage was using a tamping iron (a long hollow cylinder of iron weighing more than 6 kilos) to compact explosive powder into the rock ready for a blast. The iron rod hit the rock, creating a spark that ignited the explosives. The rod was propelled through Gage’s skull, entering through his left cheekbone and exiting through the top of his head. It was later found some 30 yards away from Gage, “smeared with blood and brain”.

Despite his horrific injury, within minutes Gage was sitting up in a cart, conscious and recounting what had happened. The doctor cleaned and dressed his wound, replacing fragments of the skull around the exit wound and making sure there were no fragments lodged in the brain by feeling inside Gage’s head with his finger. Despite Harlow’s efforts, the wound became infected and Gage fell into a semi-comatose state. His family did not expect him to survive: they even prepared his coffin. But Gage revived and later that year was well enough to return to his parents’ home in New Hampshire.

In 1850 Professor of Surgery at Harvard University, reported Gage to be “quite recovered in faculties of body and mind”. It seems that physically, Gage made a good recovery, but his injury may have had a permanent impact on his mental condition. The damage to Gage’s frontal cortex caused by the iron rod seems to have resulted in a loss of social inhibitions.

Describe the separation of the human brain

The human brain has two hemispheres which are bridged by the corpus callosum. This ‘bridge’, which is a bundle of fibres, is effectively a communication pathway so that the two hemispheres can exchange information.

What happens in the left hemisphere?

For most people their language processing is done in the left hemisphere. Therefore, for many people, if they have a stroke on the left side of their brain, their speech is affected. Areas such as Broca’s area and Wernicke’s area are found, for most people, on the left side of the brain.

What happens in the right hemisphere?

The right hemisphere seems to be particularly dominant for recognising emotions in others. Work has shown that, if a photo of a face that has been split so that one half is smiling and the other half is neutral, is shown to someone, the emotion shown in the left-hand side of the picture is the emotion recognised by the participant. This is probably because their right hemisphere is dominant for this task.

What are some overall differences between the right and left hemisphere?

If you ask somebody to look at a picture and to identify the small detail there will be a greater level of activity in the left hemisphere then if they look at a picture holistically (all together), which prompts more activity in the right hemisphere (Fink, Halligan et al., 1996). This suggests that the left hemisphere focuses on detail and the right hemisphere processes overall patterns.

What are 4 lobes in the brain?

Frontal

Temporal

Parietal

Occipital

Describe the primary motor cortex

M1 is located in the frontal lobe of the brain. The role of the primary motor cortex is to generate neural impulses that control the execution of movement. Signals from M1 cross the body’s midline to activate skeletal muscles on the opposite side of the body, meaning that the left hemisphere of the brain controls the right side of the body, and the right hemisphere controls the left side of the body. The amount of brain matter devoted to any particular body part represents the amount of control that the primary motor cortex has over that body part.

Describe the somatosensory centres

The somatosensory system is the part of the sensory system concerned with the conscious perception of touch, pressure, pain, temperature, position, movement, and vibration, which arise from the muscles, joints, skin, and fascia. It perceives touch, so the amount of neural connections needed dictates the amount of somatosensory cortex needed for that part of the body. The touch sensitive areas such as the face require a larger proportion of the somatosensory cortex than say the trunk, which does not require a high level of sensitivity.

Describe the primary visual cortex

In all mammals studied, it is located in the posterior pole of the occipital cortex. It is the simplest, earliest cortical visual area. It is highly specialized for processing information about static and moving objects and is excellent in pattern recognition. Individuals with damage to that area report no vision of any kind: conscious vision, visual imagery while awake or in their dreams.

The visual information is transmitted along two pathways, one containing the components of the visual field and the other being involved in the location within the visual field.

Describe the primary auditory cortex

The human brain has two primary auditory cortices, one in each hemisphere.

The primary auditory cortex in both hemispheres receives information from both ears via two pathways that transmit information about what the sound is and its location. If the primary auditory cortex is damaged it does not lead to total deafness. Sounds can still be heard but if they require complex processing such as music, then this ability is no longer present.

Describe the Broca’s area

Broca's area is one of the main areas of the cerebral cortex responsible for producing language. This region of the brain was named for French neurosurgeon Paul Broca who discovered the function of this area while examining the brains of patients with language difficulties. There are several brain areas that play a vital role in speech and language comprehension. Broca's area helps us to accurately communicate our ideas to others through speech. It is also involved in language comprehension.

Describe Wernicke’s area

This is a separate area of language processing which seems to have specific function. In 1874, Karl Wernicke, who worked at a hospital in Germany, found that patients who had damage in an area close to the auditory cortex had specific language impairments. These included the inability to comprehend language and anomia, which is when someone struggles to find the word they need. However, Wernicke noticed that these people did have fluent speech, when they could access the words quickly. This led Wernicke to suggest that the area was important for understanding language and accessing words.

What is the link between the hemisphere’s called?

Corpus callosum

When was Sperry’s split brain research?

1968

What was Sperry’s aim?

The aim of this study was to investigate the effects of hemisphere deconnection and to show that each hemisphere has different functions

What was Sperry’s method?

The participants were 11 split-brain patients, that is, they were patients who had undergone disconnection of the cerebral hemispheres.

The method used was a natural experiment. The quasi-experiments involved comparing the performance of the 11 participants on various tasks with the performance of people with no inter-hemisphere disconnection.

Sperry used a number of ingenious tasks in order to investigate lateralisation of brain function. The tasks were carried out in laboratory conditions, using specialised equipment and were highly standardised. The tasks all involved setting tasks separately to the two hemispheres. One of the tasks used to send information to just one hemisphere involved asking participants to respond to visual information. Another of the tasks used to send information to just one hemisphere involved asking patients to respond to tactile information.

It is also possible to present Auditory and olfactory stimuli to one side of the brain using various methods of blocking the unused ear or nostril.

What were Sperry’s results?

When participants were presented with an image in one half of their visual field and then presented with the same image in the other half of the visual field they responded as if they had never seen the image before. If the same image was presented in the original visual field the participants were able to recognise the image as one they had seen before.

Participants were not able to give a description of an image that was presented to the left hand side of the visual field. The image was either not noticed or just appeared as a flash.

If two symbols were presented simultaneously, one on either side of the visual field and the participant was required to draw with their left-hand what they had seen, they would draw the left visual field symbol. If they were required to say what they had just drawn, the participant would say by name, the right visual field symbol.

Objects put in the participants hand for identification by touch could be described or named in speech or writing if they were in the right hand but if placed in the left hand, the participant could either only make wild guesses or even appeared to be unaware that anything at all was present. However, if the object was taken from the left hand and placed in a ‘grab bag’, or was scrambled among other test items, the participant was able to search out and retrieve it with their left hand.

Through the case studies Sperry found that the hemisphere disconnection did not appear to affect the patients intelligence or their personality. The effects of the surgery did seem to have affected the patients in that they had short-term memory deficits, limited concentration spans and orientation problems.

What does brain plasticity mean?

It is referring to the brain's ability to change at any age. As you would imagine, this flexibility plays an incredibly important role in our brain development and in shaping our distinct personalities. 

The term Neuroplasticity gained prominence in the latter half of the 20th century, when new research showed many aspects of the brain remain changeable even into adulthood. This notion contrasts with the previous scientific consensus that the brain develops during a critical period in early childhood, then remains relatively unchangeable afterward.

What are the 3 ways that the body can replace axon function in the brain after trauma?

Increased Brain Stimulation

Axon Sprouting

Denervation Supersensitivity

How does increased brain stimulation replace axon function in the brain after trauma?

As neurons are damaged there is an effect on the neighbouring neurons as they no longer have input. This happens with the hemispheres too. Although damage may only be on one side, the other hemisphere functions at a lower level too, as it has reduced input. Work by Takatsuru et al. (2009), demonstrated that if the undamaged hemisphere is stimulated, recovery from a stroke can be improved.

How does axon sprouting replace axon function in the brain after trauma?

When an axon is damaged its connection with a neighbouring neuron is lost. In some cases, others axons that already connect with that neuron will sprout extra connections to the neuron, replacing the ones that have been destroyed. It is compensating for the loss of a neighbour. This occurs for the most part two weeks after the damage happens. It helps replace function, but only if the damaged axon and the compensatory axons do a similar job. If not, problems can occur with function.

How does denervation supersensitivity replace axon function in the brain after trauma?

This occurs when axons that do a similar job become aroused to a higher level to compensate for the ones that are lost. However, it can have the unfortunate consequence of over-sensitivity to message such as pain. This increases the pain levels in an individual.

What is functional recovery of the brain?

Much recovery after trauma is due to anatomical compensation, brought about by intensive rehabilitation. The brain learns to compensate for function. The brain can be taught to learn how to use the working faculties and function to compensate for the ones that are lost forever.

What are some factors that affect recovery of the brain after trauma?

Perseverance

Physical exhaustion, stress and alcohol consumption

Age

Gender

How does perseverance affect brain recovery?

Functional recovery after brain trauma is dependent on assessment and perseverance. Sometimes a function may appear to be lost but that may be because the individual affected may not be trying and takes the view that it is unrecoverable. Animal studies have shown that when a monkey has a ‘deafferented’ limb (when a limb has lost its sensory input), it will not try to use it. However, if the functioning of the other limbs becomes damaged, then it will have no option than to use the deafferented one. The motor nerves are still connected to the limb, but because the sensory nerve connection is damaged the monkey does not feel as though it can move the limb (Taub & Berman, 1968).

How does physical exhaustion, stress and alcohol consumption affect brain recovery?

When function is recovered in an individual it is important to remember that often the function is used with considerable effort and although the person can do a task, they are often fatigued by the effort. It is similar to walking through deep mud rather than on a tarmac road surface. Other factors such as stress and alcohol consumption can affect the ability to use any function that has been regained (Fleet & Heilman, 1986).

How does age affect brain recovery?

There is a deterioration of the brain in old age and this therefore affects the extent and speed of recovery (Corkin et al, 1989). A study by Marquez de la Plata et al. (2008) found that, following brain trauma, older patients (40+ years old) regained less function in treatment than younger patients and they were also more likely to decline in terms of function for the five years following trauma. The contemporary case study of Danelli et al. (2013) illustrates the extent to which a young brain can regain function following severe damage.

How does gender affect brain recovery?

There is research to suggest that women recover better from brain injury as their function is not lateralised (concentration in one hemisphere). Ratcliffe et al. (2007) examined 325 patients with brain trauma for their level of response for cognitive skills to rehabilitation. The patients were 16-45 years old at injury, received rehabilitation at a care facility, and completed a follow-up one year later. None of them had learning problems prior to the trauma. When assessed for cognitive skills, women preformed significantly better than men on tests of attention/working memory and language whereas men outperformed females in visual analytic skills. Overall, the results suggest a better recovery for women. However, the results did not control for performance pre-injury, so this could have influenced results.

Research is, however, mixed in this area, so clear overall conclusions cannot be drawn.

When was Schneider et al research?

2014

What was schneider et al’s aim?

Schneider et al. investigated whether time spent in education would be a factor in recovery from brain injury.

What was schneider et al’s procedure?

769 people who had suffered head injuries from road traffic accidents and falls were studied. They had all been treated in the emergency room in the hospital and followed a programme of rehabilitation. Their progress was monitored.

What was schneider et al’s findings?

1.      Of the 769 participants, 24% did not finish school, 51% had 12-15 years of education and 25% had graduated from university, with an undergraduate degree or higher level of qualification.

2.      One year after the injury 28% of the participants had made a full recovery and were back in education or working.

3.      39 % of the graduates were left free of disability, whereas of those who had left school early, only 10% made a full recovery.

4.      The researchers are not sure why these results arose but argue it may be that more educated people make more effective use of the brains, which strengths them.

5.      They found similar injuries had very different outcomes, and that one of the factors implicated in successful outcomes was the amount of time spent in education. Schneider suggests that people with an increased cognitive capability might heal in a different way to those who have a low capability – it may be that some people have a greater ability to compensate for function. They are seven times more likely to make a full recovery than people who did not finish school.

What was schneider et al’s conclusion?

People who have remained in education for longer have a greater ‘cognitive reverse’, which means they are less likely to be left permanently disabled after a head injury. Their brains are better able to maintain function in spite of damage, which makes them more likely to regain function following a brain trauma.

What are 4 ways of studying the brain?

fMRI

EEG

ERP

Post-mortem examinations

How does an fMRI work?

It is a functional neuroimaging procedure using MRI technology that measures brain activity by detecting changes associated with blood flow. This technique relies on the fact that cerebral blood flow and neuronal activation are coupled. When an area of the brain is in use, blood flow to that region also increases.

The primary form of fMRI uses the blood-oxygen-level dependent contrast, discovered by Seiji Ogawa. This is a type of specialized brain and body scan used to map neural activity in the brains of humans or other animals by imaging the change in blood flow related to energy use by brain cells. Since the early 1990s, fMRI has come to dominate brain mapping research because it does not require people to undergo shots, surgery, or to ingest substances, or be exposed to ionising radiation, etc.

How does an EEG work?

It is an electrophysiological monitoring method to record electrical activity of the brain. It is typically non-invasive, with the electrodes placed along the scalp, although invasive electrodes are sometimes used in specific applications. EEG measures voltage fluctuations resulting from ionic current within the neurons of the brain. In clinical contexts, EEG refers to the recording of the brain's spontaneous electrical activity over a period of time, as recorded from multiple electrodes placed on the scalp.

How does an ERP work?

It is the measured brain response that is the direct result of a specific sensory, cognitive, or motor event. More formally, it is any stereotyped electrophysiological response to a stimulus. The study of the brain in this way provides a non-invasive means of evaluating brain functioning in patients with cognitive diseases.

How does a post-mortem examination work?

Post-mortem examinations are when a person’s body, including the brain, is examined after they have died. They can be used to see where damage had occurred in the brain and how that might explain behaviour exhibited by the individual prior to death.