Brain Mind and Education

•Blackboard, Timetable Issues

•Books for this unit:

Paul Howard-Jones

Howard-Jones, P. (2010) Introducing Neuroeducational Research, Abingdon: Routledge.

Ward, J. (2010) A Student’s Guide to Cognitive Neuroscience (2nd Edition). New York: Psychology Press.

Neurons and Neuroanatomy• Neurons and other cells• Neural networks• How communication occurs

within them (AP)• Our nervous systems – key

orientation terms• Neuroanatomy: 3 parts of

brain, cortex (lobes) and some subcortical structures.

• Brodmann areas, some associated functions

• Locating function

© MethoxyRoxy / Wikimedia Commons / CC-BY-2.5

The neuron- a type of cell

© Quasar Jarosz . Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.3 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license is included in the section entitled "GNU Free Documentation License".

Dendrite

Axon

Node of Ranvier

Presynaptic terminal

Myelin sheathNucleus

Schwann cell

The membrane of the neuron has selective ion channels:

At rest , Potassium ions (K+) cross the membrane easily

Chloride ions (Cl-)and sodium ions (Na+) more difficulty crossing

Negatively charged protein molecules (A-) inside the neuron cannot cross

Also, a PUMP moves 3 Na+ out for every 2 K+in.

Result: Resting Potential (- 70 mV)

Resting Potential - neurons not sending signals….

outside

inside

Image attributed to @ Chris 73, updated by en:User:Diberri, converted to SVG by tiZom”/Wikimedia Commons / CC-BY-SA-3.0

Threshold (-55 mV) - something has to get the cell this far depolarized: then it all happens!

Sodium Channels open

More sodium Channels open

Sodium Channels close

Potassium Channels open Potassium

Channels close

LISTEN: Activity from a ganglion cell after the tooth of an anesthetized rat was tapped 5 times: ANIMATION

© Laurentaylorj /Wikimedia Commons / CC-BY-SA-3.0

Networks of neurons•Stimulated peripheral neuron depolarises neuron beyond threshold

•AP’s conveyed along axon often to dendrites of another neuron (via a connection: synapse)

•from whence signal may continue.

•So, neurons generate & mediate electrical signals in a complex and interconnected manner.

Image © Paul Howard-Jones 2014

Information Superhighways: Axons and Myelin

Myelin insulates, reducing losses and speeding up transmission from one node of Ranvier to the next

Loss of myelin (muscle weakness and seizures) associated with MS, and (temp.) viral infections

Myelin is whitish and gives rise to the colour of “white matter”N.B. Nuclei (s. nucleus) Densely packed grey matter areas

Afferent axons carry information to a particular place in CNS

Efferent axons carry information away

Cells other than neurons

Glial Cells: the housekeepers of the CNS:

Macroglia: Astrocytes (remove XS potassium ions, mop up leaked neurotransmitters)

Oligodendrocytes - make myelin - one cell can wrap several axons

Schwann cells - make myelin too- wrap single axons (chiefly peripheral NS)

Microglia: Cleaning up CNS debris – multiply with damage

Astrocyte© Magnus Manske / Wikimedia Commons / CC-BY-SA-3.0

Oligodendrocyte

Nervous systems (where neurons live)

Peripheral

Central

Brain

Spinal cord

Autonomic

- controls internal organs/glands

Somatic

- sensory to CNS (I/P), motor nerve fibres to skeletal muscle (O/P)

Sympathetic

- fight or flight, increasing energy use

Parasympathetic

- rest and digest, reducing energy

Key Orientation Termsdorsal/superior

ventral/inferior

caudal/ posterior

rostral/anterior

Image © Paul Howard-Jones

Ipsilateral: same sidebilateral: both sidesContralateral: oppositeMedial: towards middleLateral: away from middle

Proximal: nearDistal: far

Planes:

Sagittal: down middle Horizontal: horizontalCoronal: vertical between ears

More Key Orientation Terms

Ipsilateral Contralateral

lateral

brain stem (life support)

Neuroanatomy

internal organs input/output

fight/flight rest/digest

(Rhombencephalon)

© Looie496 created 2001

Brain = forebrain + midbrain + hindbrain

Brain = forebrain + midbrain + hindbrain

Brain 6wks after conception Adult brain

Image © Paul Howard-Jones 2014

Hindbrain

Medulla Pons Cerebellum

– maintains breathing, blood circulation

- relays movement, regulates breathing, taste and sleep

- motor coordination, precision, and accurate timing…and much more..

© Was a bee / Wikimedia Commons / CC-BY-SA 2.1 © Was a bee / Wikimedia Commons / CC-BY-SA 2.1

Tegmentum: nuclei connected to motor controlTectum: controls and relays sensor information

tegmentum

tectum

Midbrain

© Lypothymia. Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license is included in the section entitled "GNU Free Documentation License".

Hypothalamus: (= below thalamus) maintains internal environment of body (homeostasis)

Forebrain – Diencephalon -> (caudal part of forebrain)

Thalamus: sensory relay to cerebral cortex

© Was a bee / Wikimedia Commons / CC-BY-SA 2.1

Forebrain – Telencephalon ->CORTEX

+ many subcortical structures (striatum, amygdala, hippocampus etc)

Brain Stem (life support)

Neuroanatomy

The human cerebral Cortex is highly folded (original area = double page of tabloid newspaper)

gyrus/gyri = ridge(s)

sulcus/sulci = valley (s)

Cerebral hemispheres- Separated by the longitudinal fissure (red below)– connected by commissures, esp: corpus callosum (bundles of myelinated axons)

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Four lobes

Image © Paul Howard-Jones 2014

Hidden cortex: the cingulate (=“island”) cortex

Image © Paul Howard-Jones 2014

Find the region…..and mark on your colouring book

• Inferior frontal sulcus

• Superior temporal gyrus

• Dorso-lateral prefrontal cortex (DLPFC)

• Superior frontal gyrus

• Anterior cingulate

Dorso-lateral prefrontal cortex (DLPFC) – band running across top of frontal lobes

Superior temporal gyrus – highest ridge travelling along the temporal lobe

Inferior frontal sulcus – lowest valley travelling along the front

Anterior cingulate - front of the large inner island

Superior frontal gyrus – highest ridge along frontal lobe

Medial/Sagittal section

Images © Paul Howard-Jones 2014

Brodmann Areas (or regions)

• Brodmann divided according to cytoarchitecture (organization of cells)

• BA 1, 2, 3 = primary somatosensory cortex

• 4 = motor cortex

• 5, 7 = secondary sensory cortex

• 6 = supplementary motor area (medial) and premotor cortex (lateral)

• 9/46 = dorsolateral prefrontal cortex24, 32 = anterior cingulate cortex 17 = primary visual cortex

41 = primary auditory cortexmedial or sagittal section

Functional Architecture - some initial principles and warnings...

* Memory, attention, emotion, etc. are more complex than sensory and motor functions – no one part of the brain is responsible for these. (Higher functions such as creativity even more complex)

* Avoid Phrenology!

The complexities of touching a cup of soup….

+

Distributed multimodal activations will instigate further even more complex activations (type of handle, spilling, burning tasty cups of soup – tomato – mmmm -> anticipation in the striatum) and anterior cingulate (concentration), frontal cortices (decision-making )…..

motor somatosensory

parietal

premotor posterior parietal

parietal

temporal association

cingulate

parahippocampal

The complexities of touching a cup of soup….

Motor and somatosensory are topographically organised (fingers, hand, arm, etc) and close – good to have input/output close together – feeling/moving

e.g. Information from the thalamus reaches somatosensory cortex, and from there to motor and also to there into a unimodal somatosensory association area – allowing the shape to be formed from touch.

From here, it feeds to premotor areas (e.g. preparing movement in respect of feeling the shape), and to higher order more posterior unimodal association areas.

It then converges with information from other sensory systems in multimodal association areas, e.g parahippocampal, temporal association and cingulate cortices

Image © Paul Howard-Jones 2014

Activity via blood flow with radioactive water

- or via glucose metabolism with radioactive deoxyglucose

•Accurate targeting using chemical messengers

•Poor spatial and temporal resolution, safety limitations

PET - Positron Emission Tomography

Locating brain function …..

- records the low level electrical fields created by neural activity.

Very good temporal resolution, good for children.

Spatial resolution not great –but improves with number of electrodes!

Can use with specific behavioural markers – event-related potentials (ERP’s)

EEG - Electroencephalography

© Kristina Walter / Wikimedia Commons / CC-BY-SA-3.0 / GFDL

Theta 4 Hz to 7 Hz - relaxed, meditative, and creative states.

Alpha 7 Hz to 14 Hz – emerges with relaxation

Beta 15 Hz to about 30 Hz – dominant when anxious

Copyright (c) Hgamboa Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.3 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license is included in the section entitled "GNU Free Documentation License“.

fMRI

- functional Magnetic Resonance Imaging

- Blood flow links to neural activity: active neurons consume oxygen, but increased blood flow occurs without matched oxygen extraction - causing an overall increase in blood oxygen.

- Hemaglobin (blood) differs in its magnetic properties from dioxyhemaglobin (oxygenated blood) and thus has a different magnetic resonance (MR) response to a magnetic field (being pulsed by radio waves).

- Differences in MR response allow an image to built up of the blood oxygenation. By subtracting the data from two conditions, which differ only with respect to the cognitive function being studied, brain activity due to the function can be mapped from the Blood Oxygenation Level Dependent (BOLD) signal.

Anatomy Function

fMRI - functional Magnetic Resonance Imaging

Spatial resolution (visual detail): Very good

Temporal resolution: OK - in terms of seconds

Comfort of participants and convenience: Not great really – loud sound, confined space

Apparently no health limit

Image © Paul Howard-Jones 2014

Image © Paul Howard-Jones 2014Image © Paul Howard-Jones 2014

www.cricbristol.ac.uk

Summary

• Neurons and other cells• Neural networks• How communication occurs within them (AP)• Our nervous systems – key orientation terms• Neuroanatomy: 3 parts of brain, cortex

(lobes) and some subcortical structures. • Brodmann areas, some associated functions• Locating function