Systems Neuroscience: Brain Architecture

Front 1

Why do we have brains?

Back 1

Because they promote survival & reproduction.

Front 2

What are brains a product of?

Back 2

Biological evolution - essential concepts about evolution are relevant.

Front 3

What is Richard Dawkins - Selfish Gene?

Back 3

All biological systems produce more offspring then can survive.

Probabilistic nature of conception leads to variability in offspring.

The world is a harsh place, where only those able to solve problems of life, survive & reproduce - natural selection.

Therefore biological characteristics (including the brain!) are 'sculpted' by evolution to solve life's brain - process has been going for millions of years, so there's a profusion of solutions running around.

Front 4

What are the evolutionary problems solved by the nervous system?

Back 4

Basic problems associated with staying alive and reproducing.

Front 5

In a changing world, what is the key to survival? Give examples.

Back 5

Flexibility is key to survival.

- Ability to model/appreciate many aspects of the physical world accurately - sensory processes.

- The ability to move & interact with the physical world - motor systems

- An appreciation of context - integration of information

Front 6

Across the phylogenetic scale, we see increasingly sophisticated solutions - but what stays the same? Describe.

Back 6

The fundamental brain architecture!

Reflected in systematic changes in brain structure - e.g. some have got more elaborate/bigger.

But basic architectural organisation been retained within brain of all vertebrates.

Indicates why studies of lower species, e.g. rats, can inform us about the human brain operates.

Front 7

What are the three planes of section?

Back 7

Coronal - front/back

Saggital - medial/lateral

Horizontal - top/bottom

Front 8

Describe the hierarchy of functional systems providing increasingly sophisticated competences?

Back 8

Learned threat - Cortex & Limbic system (Avoidance) ==> MOTOR

Loom - Sensorimotor midbrain (Avoidance) ==> AUTONOMIC

e.g. Hot flame - Spinal cord (Escape) ==> ENDOCRINE

Front 9

What are Motor, Autonomic and Endocrine systems examples of?

Back 9

Defence-related output.

Front 10

What is the fundamental concept of processing units of the vertebrate brain?

Back 10

The localisation of function, i.e. different areas of the brain perform different tasks.

Front 11

Describe the fundamental function distinction.

Back 11

1. Structures with specific function

and

2. Systems with generic function

Front 12

Give examples of structures with specific function.

Back 12

Visual cortex/midbrain superior colliculus - primary sensory areas processing information from eye.

Hand area in motor cortex & trigeminal motor nucleus in brainstem - both primary motor structures providing commands for fine movements of finger (cortex) and mouth (trigeminal)

Front 13

What are structures with generic function?

Back 13

Structure with repeating micro-architecture that processes information received from regions performing widely differing functions.

Leads to idea of general/genetic functions required for most/all tasks - e.g. attention, reward.

Front 14

What are the 3 regions of the brain that generate behavioural options?

Back 14

Sensorimotor structures:

- Cerebral cortex

- Mid brain

- Hindbrain

Front 15

What do these regions have and do? e.g. an example

Back 15

Each have sensory areas that project to motor areas that produce movement.

e.g. the Midbrain Superior Colliculus - evoked eye movements bring novel events onto the fovea.

Front 16

What are 3 structures with generic functions (name the functions too!)?

Back 16

Hippocampus - Episodic Memory

Cerebellum - Skill

Basal Ganglia - Selection

Front 17

What is the hippocampus' generic function?

Back 17

Critical for episodic memory - vital role in STM.

Essential for construction of mental images, spatial memory & navigation.

Front 18

What is the architecture of the hippocampus?

Back 18

External inputs:

Different functional systems contact different territories

Territories are spatially distributed - repeating micro-architecture is common to all territories

Front 19

Where can the hippocampus be found?

Back 19

Under the cerebral cortex, in the inner region of the temporal lobe.

Front 20

What is the function of the cerebellum?

Back 20

Damage makes many movements inaccurate, slow & uncoordinated.

Other parts of the brain issue movement commands, but this part of the brain ensures they're carried out properly.

It predicts sensory consequences of own actions, therefore they can be ignored or improved if there's an error - i.e. skill development.

Front 21

What is the architecture of the cerebellum?

Back 21

Structure is very uniform over its entire surface.

Different regions of this component have different inputs & outputs, but the same basic organisation.

Thus repeating micro-architecture performs the same operation on different inputs.

Front 22

What is the location of the cerebellum?

Back 22

Most easily seen from underneath the brain, next to the brainstem.

Front 23

Describe the re-entrant loop architecture of the cerebellum.

Back 23

All sensorimotor, cognitive & motivation/affective structures connect to the cerebellum via the re-entrant loop.

Front 24

Describe the structure of origin.

Back 24

Pons => Cerebellum => Thalamus => Structure of Origin

Front 25

What is the location of the basal ganglia?

Back 25

Above cerebellum, behind the thalamus.

Front 26

What is the function of the basal ganglia?

Back 26

Decides solution when functional (sensorimotor) systems compete.

Spatially distributed, processing in parallel, and all act through final common motor path.

Front 27

What problem does the basal ganglia seek to solve?

Back 27

The selection problem: i.e. at any which point in time, which system should be permitted to direct motor output (behaviour)?

Selection via loops through basal ganglia may provide a solution.

Front 28

Give an example of the process of the basal ganglia in the selection problem.

Back 28

A mouse:

Energy balance (food) ->

Fluid balance (drink) ->

Threat (escapes) ->

Motor resources ->

Behavioural output = feeding

Front 29

Disorders of the basal ganglia.

Back 29

Parkinson's disease, Schizophrenia, Drug addiction, ADD, and OCD.

Front 30

What happens in Parkinson's disease?

Back 30

Degeneration of ascending DA projections.

Treatment: L-DOPA (DA precursor) for many years.

Front 31

What happens in Schizophrenia?

Back 31

DA agonists induce/potentiate psychosis.

Treatment: DA antagonists = antipsychotic.

Front 32

What happens in Drug addiction?

Back 32

Most "non-therapeutically" used drugs either increase DA transmission directly (amphetamine, cocaine).

OR interact with it indirectly (nicotine, heroin, etc.)