neuroscience

Neurobiology

anatomy and cell biology of the nervous system~

Neurophysiology

physiological basis of resting and action potentials~

Neurochemistry

neurotransmitters, synapses and receptor biology~

Neuropathology

outline of common neurological diseases~

Trajectories of change in brain structure and function across the lifespan

• Structural topology develops non linearly across the lifespan and is strongly related to cognitive trajectories whereby the brain undergoes changes throughout life

• Brain development was shown was to occur in five distinct epochs with turning points in childhood, midlife and old age

• Five major phases represent key turning points at the ages of about 10, 30, 60 and 80

• Even though the brain changes most significantly during childhood, it remains adaptable well into old age~

Examples of neurological abnormalities

• Acquired neurological disorders

• Neurological injury/ trauma

• Genetic neurological diseases

• Genetic susceptibilities towards neuropathology

• Mental or neurodevelopmental disorders

• Neurological co morbidities of common diseases

• Medical treatment or drug related neuropathology

• Pharmacogenetic diseases of the nervous system

• Neurotoxicological insults to the nervous system

• Neurological speech disorders

• Aging related neurodegeneration~

Common neurological disorders

• Brain trauma

• Ischemic stroke

• Haemorrhagic stroke

• Motor neuron disease

• Brain cancer

• Dementia

• Multiple sclerosis~

Common neurological diseases

• Headache

• Facial pain/ paralysis

• Dizziness and vertigo

• Syncope and epilepsy

• Cerebrovascular disease

• Cerebral tumours

• Parkinsons's disease

• Head trauma/ injury

• Cerebral palsy

• Cerebrellar ataxia

• Spinal cord injury/ diseases

• Peripheral nerve disorders

• Motor neuron disease

• Dementia

• Huntingtons disease

• Multiple sclerosis

• Neuronal infectons~

Phineas Gage (1848)

• Accident that put an iron rod through his skull, pentrating his left cheek and exited through skull

• Observations made my Dr. John Harlow, who treated him afew months after accident

• The balance between his " intellectual faculties and animal propensities" seemed gone. He could not stick to plans, uttered "the grossest profanity" and showed "little deference for his fellows"~

Central nervous system (CNS)

brain and spinal cord~

Behavioural and emotional issues associated with TBI (traumatic brain injury) and other brain disorders:

• Emotional problems after traumatic brain injury ( frontal and temporal lobe)

• Involuntary emotional expression disorder (IEED)~

Peripheral nervous system (PNS)

neurons and axons outside the CNS~

Peripheral nervous system sub parts

• Somatic NS- voluntary movements

• Enteric PNS- control of Gi system

• Autonomic NS

  • Sympathetic NS- mobilisation during activity

  • Parasympathetic NS- 'housekeeping' during rest~

When did the modern human brain develop?

200,000 years ago~

Typical features of a nervous system

• Segemnted structures

• Bilaterally symmetrical organisation

• Principle of crossed organisation of brain hemisphere

• Brain and spinal cord are protected by encasement in cartileage and bone structures~

3 layers of meninges

• Dura mater- outer thick layer

• Arachnoid mater- numerous connections to inner layer

• Pia mater- inner thin membrane on surface of brain and spinal cord~

Cerebrospinal fluid

• Circulates through subarachnoid space

• Absorbs physical shocks

• Transports substances to and from cells~

Evolution of human brain optimisation

• Overall size and structure specialisation

• Number of neurons and glia cells

• Length of interconnections

• Number of interconnections

• High bioenergetic consumption

• Elaborate memory system~

Neuroplasticity

CNS and PNS have relatively high potential for adaptation to environmental change and compensation of minor pathological insults~

Main brain functions (skilled movements and social behaviour)

• Collection of essential information from surrounding environment- afferent (incoming) information => sensory information coming into CNS

• Integration of essential information for creation of sensory reality- two directional neural information flow and signal integration

• Production of commands to control muscle movement- efferent (outgoing) information=> motor pathway information leaving CNS

• Highly sophisticated human cognitive functions~

Neuroscience of behaviour

• Most complex behaviours probably comprise a mixture of learned and inherited actions, such as movements, vocalisations or thinking

• Main types of behavioural patterns

  • Innate ( fixed) behaviours, dependent on heredity

  • Learned flexible behaviours, dependent on learning process

• Wide ranging mammalian behaviour due to highly complex nervous system~

General principles of the nervous system

• Perceptual world of the brain

• Neuroplasticity: constant change in NS functioning

• Crossed organisation of the brain hemispheres

• Hierarchal and parallel organisation of brain systems

• Divisions of sensory and motor systems exist throughout the NS

• Brain function is both localised and distributed

• NS functioning is based on integration of neuronal excitation versus inhibition~

Three main brain divisions 1; forebrain

5 week embryo-- telencephalon and diencephalon

Adult-- cerebrum (showing cerebral cortex)  

Thalamus--- – Relays sensory information to the cerebrum – Also sends outputs from the cerebrum to other parts of the brain – Gets input from all sensory systems except olfaction

hypothalamus  - Produces hormones regulating pituitary gland, which regulates hormone secretion from other glands – Great importance for homeostasis of the body and the control of behaviour

epithalamus (not visible)-  Structures with various roles in the production of cerebrospinal fluid, control of food and water intake, and rhythmic and seasonal behaviors – Pineal gland produces melatonin (hormone that controls sleep and wake cycles)~

Three main brain divisions 2; midbrain

Three main brain divisions 2; midbrain:

5 week embryo-- mesencephalon- Processes several types of sensory input (vision, olfaction, and audition) & controls sophisticated tasks. Tracts pass this information to other parts of the brain for further processing and interpretation.

Adult-- midbrain~

Three main brain divisions 3; hindbrain

5 week embryo--metencephalon and myelencephalon

Adult-- cerebellum pons- Responsible for monitoring and coordinating body movement

medulla oblongata- Coordinates many basic reflexes and bodily functions~