The brain

The original view was a version of bottom-up processing.

• Bottom-up processing - processing that comes from the bottom; low-level components

The new view is a version of top-down processing.

• Top-down processing - processing that comes from the higher-level components; including the brain

Early evolutionary theorists' points to the brain as a means of natural evolution (e.g. Darwin, 1859).

Early scientific advances:

• Brain damage in specific parts of the brain resulted in specific cognitive impairment
• Stimulation of specific brain areas would result in very 'real' experiences

Cognitive neuropsychology and neuroscience were soon born out of these early advances.

Studies have since been able to uncover some key information about cognitive processes in sport performers.

E.g. the infamous Action-Observation Network.

• AON - consolidation of brain and how each part works (you need neuro-imaging in order to do this)

Studies have also been able to uncover differences in cognitive processes as a result of motor learning.

There are newer interventions that help us with looking into things such as, ADHD and depression.

3 sub-components:

• Gross organisation of the brain - specific brain structures
• The brain interacts with peripheral nervous system
• Neuron function

The cortex has four lobes: frontal, parietal, occipital and temporal.

Subcortex:

• Thalamus
• Basal ganglia
• Limbic system
• Cerebellum

The brain folds into different ridges and indentations to allow for a greater surface area.

• Gyrus - ridge
• Sulcus - indentation
• Cortex - the outer layer

Dendrites are branches that gather signals.

Axon:

• Transport line from neuron to neuron
• Fat which acts as an insulator
• Length ranges

Myelin: 

• Protects the axon
• Speeds up the conduction of the electrical signal

The cell body calculates polarity, electricity; the charge of electrical signals.

Signals gather in the dendrites.

Sums electrical signals in the cell body.

If reaches the threshold, cell fires-sends an action potential down the axon causing presynaptic terminals to release neurotransmitters into the synapse.

Neurotransmitters cause the next dendrite to be excited or inhibited.

Neurotransmitters are the chemical compounds that exist to transmit the electrical signal between neurons. They are formed differently and characterised differently; they're not all the same.

Types:

• Adrenaline - fight-or-flight neurotransmitter
• Noradrenaline - concentration neurotransmitter
• Dopamine - pleasure neurotransmitter
• Serotonin - mood neurotransmitter
• Gaba - calming neurotransmitter
• Acetylcholine - learning neurotransmitter
• Glutamate - memory neurotransmitter
• Endorphins - euphoria neurotransmitter

Synaptic transmission is the process by which one neuron communicates with another.

Information is passed down the axon of the neuron as an electrical impulse known as an action potential. Once the action potential reaches the end of the axon, it needs to be transferred to another neuron or tissue. It must cross over the synaptic gap between the presynaptic neuron and post-synaptic neuron. At the end of the neuron (in the axon terminal) are the synaptic vesicles, which contain chemical messengers, known as neurotransmitters. When the electrical impulse (action potential) reaches these synaptic vesicles, they release their contents of neurotransmitters. Neurotransmitters then carry the signal across the synaptic gap. They bind to receptor sites on the post-synaptic cell, thereby completing the process by synaptic transmission.

Some neurons have a positive charge, and some have a negative charge which results in activation and inhibition. Depending on the area of the brain, the neurons will turn on or off.

Over time, connections between the neurotransmitters become inhibited with each other which means that not all neurons 'fire' at the same time.

Neurons under a microscope; some are bigger than others and some are more electrically charged than others.

Grey matter is predominantly neurons in cell bodies which can be found in the cortex of the brain; the thin layer.

White matter is the support network for the grey matter.

• Provides maintenance for the grey matter
• Keeps the brain healthy
• Keeps the brain lubricated
• Keeps the brain from toxins
• Keeps the brain performing like it should

Neurons - process information.

Glia - important support cells.

Types of neuroglia in the CNS:

• Ependymal cells
• Oligodendrocytes
• Astrocytes
• Microglia

Types of neuroglia in the PNS:

• Satellite cells
• Schwann cells

CNS:

• The CNS connects the brain and the spinal cord via the brain stem
• Neurons have to communicate with the rest of the body through the CNS
• The CNS has a general flow and then the tracts get thinner to allow for it to get to more specialised regions

PNS:

• The PNS carries sensory information from the brain to the body's limbs and organs. It becomes thinner to control the movement of neurons to specific areas

The different lobes respond to different stimuli.

There have been important developments in humans compared to other primates - expansion of the frontal lobes.

Important for:

• Planning
• Responding
• Social appropriateness

Frontal lobe:

• Plan; select goals and motor actions
• Respond; execute motor actions and inhibit automatic responses to distractions
• Social appropriateness

Parietal lobe:

• Integrates and processes sensory information from our thoughts and environment

Bigger limbs take up only a small amount of the brain as small body parts need more space in the brain to allow for fine motor movements.

Temporal lobe:

• Stores long-term information that are mainly composed of our knowledge, personality, and life experiences (general storage unit)

Occipital lobe:

• Process visual information; it connects directly to the eye and reads information from the retina

Railway construction accident in 1848.

Accidental explosion of a charge he had set blew his tamping iron through the left side of his, destroying the prefrontal cortex on that side.

He was treated and survived, returning home 10 weeks later.

He tried to resume work but had changed.

Before the accident, he had been their most capable and efficient forearm, one with a well-balanced mind, and who was looked on as a shrewd smart businessman.

After he was fitful, irreverent and grossly profane, showing little deference for his fellows. He was also impatient and obstinate, yet capricious and vacillating, unable to settle on any of the plans h devised for future action.

Stroke patients were asked to draw something but only draw half; they think it's done, but it's not.

This is visual neglect.

Findings:

• A higher amount of electrical stimulation before experience
• Less stimulation afterwards; it's now a learned task, so more efficient
• Less cognition - straight to behaviour - performance of behaviour

MRI - looks at a specific area of the brain.

fMRI - looks at an area of the brain whilst performing an action.

EEG - allows us to see the frequency of stimulations of different parts in a given time period.

It regulates the frequency and intensity of motor activity. 

It also guides attention and learning.

It is the brains sensory relay for all senses except smell.

Neuropsychology patients - e.g. Phineas Gage.

• See how patients behave and relate behaviour to areas of brain damage

Electrical stimulation - e.g. during surgery for epilepsy.

• Stimulate areas of the brain and see what behaviour occurs

Functional neuroimaging - e.g. fMRI.

• Have a participant perform a task in the scanner and measure brain activation

Electrical recording of brain activity.

• Recording from neurons
• Surface electrodes; i.e. on the scalp

Shape- e.g. dendrite density.

Size.

• Axon length
• Axon width: speed
• Myelin sheath present: speed

Spatial arrangement.

• Sensory: dendrite in periphery; axon towards brain (afferent)
• Motor: dendrite from brain; axon towards periphery (efferent)
• Interneurons: neuron-to-neuron connections

Special sensitivities and outputs.

• Sensory neurons: dendrites sensitive to certain physical stimuli
• Other neurons: dendrites affected by neurotransmitters

The brain is organised according to function.

• I.e. the different areas of the brain have specific functions

If you know what areas of the brain are involved in a task, then you know something about how the mind breaks down the task.

It helps you to understand why a person is doing well/not doing well at a task.