Unit 3 Topic 3 - Brain and Nervous System

Give examples of three bodily functions that decrease their activity as a result of the action of the sympathetic nervous system.

1. Digestive process 2. Bladder relaxes

Briefly describe the two main function of the autonomic nervous system?

1. connects the CNS to the body's internal organs (heart, liver, stomach) and glands (sweat, adrenal glands) 2. responsible for regulating the activity of the visceral muscles, organs and glands

give 3 effects of parasympathetic NS

1. heart rate decreases 2. blood pressure decreases 3. pupil constriction

name 3 effects of the sympathetic nervous system

1. heart rate increases 2. dilation of pupils 3. breathing rate increases

Describe the 3functions of the spinal cord

1. receives sensory information from the body through the PNS and transmits it to the brain 2. receives information from the brain and relays it to the body through the PNS to control muscles, glands and internal organs 3. initiates a spinal reflex

Briefly describe the two main functions of the somatic nervous system?

1. responsible for voluntary movement of the skeletal muscles 2. carries sensory information from the sensory receptors to the CNS and motor messages from the CNS to the skeletal muscles

What are the two main functions of the peripheral nervous system?

1. transmits sensory information to the CNS 2. sends motor information from the CNS to the muscles, organs and glands

How is aphasia defined?

Aphasia is a language disorder apparent in speech (comprehension or production), writing or reading produced by injury to brain areas specialised for these functions.

What are the two divisions of the peripheral nervous system?

Autonomic nervous system and Somatic nervous system

Describe the sensory and motor functions (behavioural functions) that the left and right hemispheres have in common.

Both hemispheres control the same sensory and motor functions but for different sides of the body. The right hemisphere receives sensory information from the left side of the body and controls movements on the left side of the body. And the left hemisphere receives sensory information from the right side of the body and controls movements on the ride side of the body.

Explain the meaning of the term 'hemispheric specialisation'.

Hemispheric specialisation refers to one hemisphere having specialised functions or exerts greater control over a particular function. Both left and right hemispheres are involved in nearly all functions, usually acting together in a coordinated interactive way.

Describe the relationship between the size of the cerebral cortex and the mental capabilities of an organism.

It is believed that the size of the cerebral cortex is linked to the mental capabilities of an organism. The bigger the cerebral cortex, the more capable that organism is of behaviour we regard as intelligent, such as language used, planning, problem solving, reasoning and decision making. And therefore it has better chance of survival due to its ability to learn and adapt to a complex and changing environment.

Explain Brocas Aphasia ( location, problems (4), patient awareness)

Location - damage to the Left frontal lobe near motor cortex problems - Problems - 1. non-fluent speech/articulation difficulties, pauses and broken speech 2. words mispronounced 3.Speech lacks grammar - verbs and nouns only 4. Partial or complete loss of ability to recall names of people and places (anomia) patient Patient awareness -Most patients are usually aware of their language difficulties and have a clear understanding of their condition.

Explain Wernickes Aphasia ( location, problems (3), patient awareness)

Location - damage to the left temporal lobe near parietal cortex Problems - 1. Difficulty understanding and producing written and spoken language,that makes sense to others, 2. Nonsense words used - meaningless words 3. Partial or complete loss of ability to recall names of people and places Patient - Patients have little or no conscious awareness or understanding of their condition

The areas of the cerebral cortex are organised into three broad categories: sensory cortex areas; motor cortex areas; association cortex areas. Briefly describe the functions of these areas.

Motor - receives, processes and sends information about voluntary movement. Sensory - receive and process information from the senses Association areas - integrates motor, sensory and other information

Name and the function of the primary sensory/motor area, functions of the association area (3) and function of language area of the TEMPORAL LOBE

Primary auditory cortex: receives and processes auditory information (sounds), Association area - Recognising faces, Emotional responses to sensations and memories, Object identification Language area - Wernicke's area: responsible for speech comprehension - meaning and understanding of written and spoken language

Name and the function of the primary sensory/motor area, functions of the association area and function of language area of the FRONTAL LOBE

Primary motor cortex: Controls voluntary bodily movement and functions contralaterally. Parts responsible for movement of the lower parts of the bottom are located at the top of the PMC and parts responsible for the movement of the upper parts of the body are located at the bottom of the PMC. The amount of PMC devoted to different body parts is in proportion to the number of motor neurons required to move that body part. Association area - Complex mental functions (planning, decision making, organising, problem solving), Personality, Control and expression of emotions Language area - Broca's area: production of articulate and fluent speech and interpretation of grammar

Name and the function of the primary sensory/motor area and 4 functions of the association area of the PARIETAL LOBE

Primary somatosensory cortex: Receives and processes sensations from the skin and body (e.g. touch, temperature, pressure and pain). It functions contralaterally. Association area - Perception of touch, temperature, pressure and pain, Senses the position of the body in space, Visual attention (spatial neglect - damage to right parental lobe), Locating objects in space

Briefly outline the procedure, results and conclusions of the Split Brain Study 2 conducted by Sperry and Gazzaniga

Procedure - Split brain patients were presented with different words on each side of the screen at the same time. They were asked to report what they had seen Results - Patients were able to read and verbally report the word presented to the right visual field (processed in the left hemisphere), The patients were unable to verbally report the word presented to the left visual field (processes by the right hemisphere) Conclusion - Left hemisphere can identify words and name them Right hemisphere can process words but cannot name them

Briefly outline the procedure, results and conclusions of the Split Brain Study 1conducted by Sperry and Gazzaniga

Procedure - Split brain patients were presented with words to their right or left visual field and asked to report wha they saw Results - When words were presented to the right visual field (processed by the left hemisphere), patients were able to read and report the words verbally, When the words were presented to the left visual field (processed by the right hemisphere), patients were unable to report the words verbally. They were able to select the item by touch from behind the screen but were unable to say why they had selected that item. Conclusion: Left hemisphere can identify words and name them Right hemisphere can identify words but cannot name them

Briefly outline the procedure, results and conclusions of the Split Brain Study 3 conducted by Sperry and Gazzaniga

Procedure - Split-brain patients were presented with a picture of an object to their right or left visual field and asked to verbally identify the object or reach under the screen and select the object by touch. Results - When a picture (e.g. hammer) was flashed to the left visual field (processes in the right hemisphere), the patient was unable to verbally name the object but could grasp the hammer with his left hand. Patients often deny seeing anything at all, When a picture (e.g. apple) was flashed to the right visual field (processes in the left hemisphere), the patient could easily name it verbally. Conclusion - The left hemisphere can identify pictures and name them. The right hemisphere can identify pictures by touch but cannot name them. The left hemisphere appears to make the executive decision concerning whether an item was present or not

Which brain area is most commonly associated with spatial neglect?

Right parietal lobe

what are the effects of the sympathetic nervous system and parasympathetic?

SYMPATHETIC: heart rate increases, blood pressure increase, breathing increases, pupils dilate PARASYMPATHETIC: production of tears, pupil constriction, reduce heart rate and blood pressure

What is the key difference between skeletal muscles and visceral muscles?

Skeletal muscles are completely inactive in the absence of motor neuron messages from the brain whereas visceral muscles (muscles involved in the activity of internal and external glands) have built-in mechanisms for generating activity and do not depend on voluntary control by the brain.

Explain what spatial neglect is. Give specific examples of behaviour demonstrated by patients with spatial neglect

Spatial neglect is a disorder in which the person affected systematically ignores stimuli on one side of the body. It usually occurs after brain surgery. E.g. patients shave eat the food on the right side of their plate, shave the right side of their face, wash the right side of their body

What are the two divisions of the autonomic nervous system?

Sympathetic and parasympathetic NS

What is the main difference between the sympathetic and parasympathetic nervous systems?

Sympathetic nervous system operates in circumstances when organisms perceives itself to be in danger or in times of stress whereas parasympathetic nervous systems operates in circumstances where it is relatively calm.

Why is the autonomic nervous system described as autonomous?

The ANS is described as autonomous because many of the organs, glands and processes under its control are self-regulated and not usually under voluntary control (e.g. heart beat, digestion, perspiration, breathing)

What is the cerebral cortex?

The Cerebral cortex is the outer layer of the brain that is made up of grey matter. It is convoluted to increase its surface area , 2 - 3 mm thick, covers most of forebrain and is divided into two hemispheres and four lobes.

What is the relationship between size of an area of primary motor cortex and density of motor neurons/fineness of movement?

The amount of primary motor cortex devoted to different body parts is in proportion to the number of motor neurons required to move that body part. Mouth and hand require more motor neurone to move, so they have more space on the primary motor cortex.

What is the relationship between size of an area of primary somatosensory cortex and density of sensory neurons/sensitivity of body part?

The amount of somatosensory cortex devoted to different parts in the body is in proportion to the number of sensory neurons in that area. The mouth and hands have more sensory neutrons (highly sensitive and associated with greater responsiveness) than less sensitive body parts so therefore the mouth and hands take up more space on the somatosensory cortex.

Briefly explain the difference between the central nervous system and the peripheral nervous system.

The central nervous system comprises of the brain and the spinal cord. The spinal cord connects the brain and the peripheral nervous system. Whereas the peripheral nervous system includes all parts of the nervous system that lie outside the brain and the spinal cord. It links the central nervous system to all other parts of the body, carrying messages to and from the central nervous system.

What is the central nervous system and what are its main roles in mental processes and behaviour?

The central nervous system consists (CNS) of brain and spinal cord. It transmits and receives messages to and from the Peripheral Nervous System (PNS).

Why does the cerebral cortex have a convoluted (wrinkled) surface?

The cerebral cortex has a convoluted surface to increase it's surfaced area (about 0.2m^2).

Outline four physical characteristics of the cerebral cortex (e.g. approx. 3mm thick, contains 75% of brain's neurons etc.).

The cerebral cortex is 2 - 3 mm thick, covers most of forebrain, contains 75% of the brain's neurons and is divided into two hemispheres and four lobes.

What is the corpus callosum?

The corpus callosum is the bridge of nerve tissue that connects the left and right hemispheres. It is made up of white matter which allows communication between different parts of the brain to occur. It contains millions of nerve fibres that interconnect corresponding areas of the cerebral cortex.

What are the main functions of the cerebral cortex?

The main function of the cerebral cortex is information-processing activities activities such as perception, language, learning, memory, thinking and problem solving. It is also involved with the planning and control of voluntary bodily movement

How is the primary motor cortex arranged in terms of area of cortex and body part?

The part of the motor cortex responsible for movement of the lower parts of the body (toes, feet, etc.) are located at the top of the primary motor cortex. The area of the motor cortex responsible for movement of upper part of the body (moth, lips, face, etc.) is located at the bottom of the primary motor cortex.

What is split-brain surgery and why is it performed?

The split-brain surgery is cutting the corpus callosum, separating the cerebral hemispheres. It disables communication between the left and right hemisphere and stops the transfer or neural impulses. It is performed to treat severe epilepsy as a last resort to help patients.

How is the primary somatosensory cortex arranged in terms of area of cortex and body part?

The upper section of the primary somatosensory cortex is devoted to lower parts of the body (e.g. legs, feet, etc.) The lower section of the primary somatosensory cortex is devoted to upper parts of the body (e.g. face, lips, mouth)

Why does it take longer for the parasympathetic nervous system to 'slow down' bodily functions than it does for the sympathetic nervous system to 'speed up' bodily functions?

This is because of the lingering presence of the hormones that are released when the sympathetic nervous system is activated. They remain in the bloodstream for some time after the threat has passed.

Why is each participant required to focus on a dot in the middle of the screen before the picture appears on the screen?

To ensure that the image flashes on the visual fields and not both eyes. The difference is that if it goes to the visual field, it will only go to one hemisphere (eg. images flashed on right visual field will go to left hemisphere & vice-versa). If it is seen by both eyes, it goes to both hemispheres.

What are the main findings of Sperry's Split Brain Experiments?

When patients were presented with words to their right or left visual field or to both fields at the same time, and asked to report what they had seen, patients were only able to read and report the words verbally that were presented to the right visual field visual field (processed by the left hemisphere). Whereas words presented to the left visual field (processed by the right hemisphere) were unable to be verbally reported but can be identified by touch. When patients were presented with a picture of an object to their right or left visual field, only the pictures flashed to the right visual field (left hemisphere) could be identified and verbally named whereas pictures flashed to the left visual field (right hemisphere) could not be verbally named but could be identified by touch. The left hemisphere can identify words and pictures and name them whereas the right hemisphere can identify words by touch but cannot name them. This occurs as the left hemisphere is responsible for language and only the left hemisphere can convert the information into spoken word and the right hemisphere is responsible for the identification of objects.

What is the function or role of the sympathetic nervous system?

becomes active when the organism perceives itself to be in danger or in times of stress. it activates the internal muscles, organs and glands to prepare the body for vigorous activity when confronted with a threatening or stressful situation (fight and flight response).

What are the cerebral hemispheres connected by?

corpus callosum.

What are the 4 lobes of the cerebral cortex?

frontal, occipital, temporal, parietal

Name and the function of the primary sensory/motor area and functions of the association area of the OCCIPITAL LOBE

primary visual cortex: Receives and processes visual information. Association area - visual perception, recognition of shapes and colours

What are the specialised functions of the right hemisphere? (7)

receive and processes sensations from the left side of the body, controls voluntary movement on the left side of the body, non-verbal tasks, spatial and visual thinking (e.g. jigsaws, map reading), creativity, appreciation of art and music, recognising emotions

What are the specialised functions of the left hemisphere?

receive and processes sensations from the right side of the body, controls voluntary movement on the right side of the body, verbal tasks (e.g. speech production), analysis (e.g. maths, sequential tasks), logical reasoning

What is the function of the parasympathetic system?

restores the body to a state of calm after threat or stressor has gone. it is responsible for maintaining autonomic day-to-day bodily functions such as digestion, normal heart rate and normal breathing and keeps the body functioning efficiently (maintains balanced state - homeostasis)

What is the main function of the corpus callosum?

to act as a 'bridge' for neural messages between the two hemispheres.

What is the function of the brain?

to organise, interpret and integrate information