Psychology Units 1 & 2 Chapter 4 & 5

Functions of the Brain

Contralateral Functions

When the left hemisphere controls movement and sensory information from the right side of the body and the right hemisphere controls movement and sensory information from the left side of the body

Corpus Callosum

Nerve tissue that connects the left and right hemispheres and serves as the main communication pathway

Left Hemisphere - Functions

Specialises in reading and writing, speech comprehension, mathematics, etc. It controls the right side of the body.

Right hemisphere - Functions

Specialises in daydreaming and fantasy, recognition of faces and patterns, judgement of rhythm and time, etc. It controls the left side of the body

Hindbrain - Location + Parts of + Main Role

The Hindbrain is located at the base of the brain around the brain stem. It includes the Medulla, Pons and Cerebellum. These control different vital, automatic responses that occur consciously

Medulla

The Medulla is responsible for controlling vital bodily functions that occur automatically and are essential for survival. This includes coughing, vomiting, blood pressure, heart rate, etc

Pons

The Pons is responsible in sleeping, dreaming and arousal from sleep. It also serves as a bridge by connecting parts of the brain together to pass on messages. For example, the Midbrain and Medulla

Cerebellum

The Cerebellum coordinates fine motor control, voluntary movement and regulates posture and balance. It helps organising and adjusting muscle activity to ensure movement is smooth and precise

The Midbrain - Location + Parts of + Main Role

The Midbrain is located in the central part of the brain. It includes the Reticular Formation and RAS. Involved in movement, processing sensory information, sleep and arousal

The Reticular Formation

The Reticular Formation helps screen incoming information and alerts information to higher centres in the brain, maintain consciousness, arousal from sleep and muscle tension. The RAS influences what we pay attention to by highlighting important information

The Forebrain - Location + Parts of + Main Role

The Forebrain is located above the midbrain and extends across the top of the brain. It includes the Hypothalamus, Thalamus and Cerebrum. This controls complex cognitive processes such as memory and sensory receptors

Hypothalamus

The Hypothalamus has a vital role in maintaining the body’s internal environment by regulating the release of hormones from various glands in the body and influencing biological needs such as sleep, hunger, thirst and emotions.

Thalamus

The Thalamus filters all information from sensory receptors (except the nose) then passes it to relevant areas of the brain for further process. Plays a role in attention with filtering unattended sensory information by giving more weight to some and less weight to others

Cerebrum

The Cerebrum includes high-level functions such as voluntary movement, thinking and reasoning, memory, emotions, language and sensory perception

Frontal Lobe

The Frontal Lobe is generally involved in our thinking, feeling and behaving. Examples of the Frontal Lobe’s functions include personality, symbolic thinking, regulating and expressing emotions, decision-making, etc

Primary Motor Cortex

Initiates and controls voluntary movements through its control in skeletal muscles. The Primary Motor Cortex in the left side of the Frontal lobe controls voluntary movement in the right side of the body, and the Primary Motor Cortex in the right side of the Frontal lobe controls voluntary movement in the left side of the body. The amount of cortex devoted to a specific body part links to the complexity of its movements. Parts that are able to move with greater precision (eg: fingers + tongue) take up more cortical space than parts with less precision (eg: shoulders + thigh)

Broca’s Area

The Broca’s area has a crucial role in the production of fluent, clear and articulate speech. It is located in the Frontal lobe

Parietal Lobe

The Parietal Lobe controls spatial reasoning and attention.

Primary Somatosensory Cortex

Receives and processes sensory information from skin and body parts. For example, lips, tongue, arms, hands, etc. The Somatosensory Cortex in the left Parietal lobe receives and processes information from the right side of the body, and the Primary Somatosensory Cortex in the right Parietal lobe receives and processes information from the left side of the body. The amount of cortex devoted to a specific body part links to the sensitivity and amount of use of the body part. For example, your lips, fingers and tongue, which are very sensitive to touch and frequently used in everyday behaviour, have more cortical space than parts that are less sensitive and used less frequently, such as the back of your legs and your hips.

Occipital Lobe

Is almost exclusively devoted to the sense of vision

Temporal Lobe

Plays an important role in memory including emotional responses to memories and sensory information, involves aspects of visual perception such as our ability to identify shapes and recognise faces

Wernicke’s Area

Has a crucial role in comprehension and coherent speech, specifically interpreting the sound of human speech. It is located below the Primary Auditory Cortex in the Temporal lobe

Structural Neuroimaging

Techniques that produce images or ‘scans’ showing brain structure and anatomy

Functional Neuroimaging

Techniques that provide views of some aspect of the brain function showing the brain ‘at work’

Neuroimaging Techniques: CT

Type of Neuroimaging: Structural neuroimaging

What is it & How does it work?: Uses x-ray equipment to scan the brain at different angles. Computer builds up a picture of a horizontal cross-section of the brain. Substance known as contrast for interpretation of the images results

When is it used?: Locating and identifying brain abnormalities and brain injuries

Strengths: Detailed information than x-rays and often used in emergencies to rapidly detect bleeding

Limitations: Black and white images show only brain’s structure , x-ray emit radiations that aren’t good for imaging tissue, early-stage abnormalities can be missed

Neuroimaging Techniques: MRI

Type of Neuroimaging: Structural neuroimaging

What is it & How does it work?: Uses harmless magnetic fields to vibrate atoms in the brain to generate an image

When is it used?: Primarily diagnosing structural abnormalities in the brain, stroke damage

Strengths: Detailed images of brain anatomy, colour, detect and display very small changes in brain anatomy

Limitations: Cannot reveal brain function, small movement can blur image, takes 20-60 minutes

Neuroimaging Techniques: PET

Type of Neuroimaging: Functional neuroimaging

What is it & How does it work?: 2D/3D colour images showing brain structure, activity and function. Tracking glucose with a radioactive tracer, injected into bloodstream before scanning

When is it used?: Record level of activity in different areas of the brain while patient engages in a mental activity (eg: imagining or remembering). Track progress of neurodegenerative diseases (eg: dementia or alzheimers)

Strengths: Show brain activity in comparison to MRI

Limitations: Less detailed than MRI

Neuroimaging Technique: fMRI

Type of Neuroimaging: Functional neuroimaging

What is it & How does it work?: Detect and record brain activity by measuring oxygen consumption across the brain. Brain areas that are more or less active during a task are identified by detecting changes in oxygen levels in the blood as it flows through the brain.

When is it used?: After trauma (eg: concussion) to track brain’s function over time, before brain surgery (eg: epilepsy) doctors map critical areas responsible for speech, movement, or memory.

Strengths: More precise and detailed than PET, take images of brain activity faster than PET, detect changes as images occur

Limitations: Doesn’t record electrical brain activity and measure of brain activity can be imprecise or delayed

Experience-expectant plasticity

Involves brain change in response to environmental experience that is ordinarily expected. If the experience does not occur when expected in a sensitive or critical period, then brain development may not occur as it should.

Experience-dependent plasticity

Involves brain change that modifies some part of its neuronal structure that is already present. It depends on exposure to various environmental experiences that are unique to each individual and may occur at any time during the life span.

Generation of New Networks

Forming new connections by the brain’s plasticity taking over or shifting functions from damaged to undamaged areas

Reassignment of Fuction

Functions that were performed by certain areas of the brain can be reassigned to other undamaged areas of the brain to compensate for changing input from the environment

Relationship between Neuroplasticity & Age

Neuroplasticity is age-dependent, so it is more effective during infancy and early childhood

Broca’s Aphasia

Laboured and hesitant speech, difficulty understanding complex speech, located in the frontal lobe, aware of their language problems, speech includes mainly nouns and verbs but lack grammar and syntax

Wernicke’s Aphasia

Difficulty comprehending speech and speaking in a meaningful way, little/no understanding of their speech problems, located in the temporal lobe, fluent speech but sounds like ‘word salad’, speech is clear and rapid but makes little sense

Ischaemic (Stroke)

When blood supply is restricted or stopped in one of the blood vessels because it is blocked. This is often due to a blood clot that has formed elsewhere in the body and travelled to the blood vessels supplying the brain.

Haemorrhagic (Stroke)

When a blood vessel supplying the brain becomes weak and bursts causing bleeding in the brain.

Epilepsy

A neurological disorder involving reoccurring, unexpected seizures brought on by interference in normal brain activity

CTE

A progressive, degeneration brain disease caused by repeated blows to the head and repeated episodes of concussion.

CTE: Biological changes

Shrinkage of brain tissue, build up of abnormal protein in the brain called Tau which disrupts cell communication