volledige college aantekeningen neurocognition voor CNP master

Neurocognition lectures

Lecture 1 – the brain and cognition over the lifespan
Rebecca Schaefer

Brain structures and anatomy

!Be able to identify different parts of a neuron!

Different types of neurons are categorized by shape and function
- Sensory
- Interneurons
- Motor

Action potentials  non-decremental: either there is an action potential
or there is not.

Synapse  action potential leads to neurotransmitter release into synaptic
cleft

Receptor cells in the postsynaptic membrane can adapt to under- or over-
use

The distribution of synapses connecting to a cell influences its excitability

Glia cells
- Astrocytes
- Oligodendrocytes  myelin for CNS neurons
- Microglial cells  fight infections & waste disposal
- Ependymal cells  ventricular surface epithelium, create CSF
- Schwann cells  myelin for peripheral neurons

Cortical cell layers  Where you are in the brain dictates how thick the
layers are

Bundles of myelinated axons
- Association fibres  connect areas within a hemisphere
- Commissural fibers  crossing to other hemisphere (homotopic or
heterotopic)
- Projection fibres  connect outward to subcortical regions

Major components of the CNS
- Forebrain
- Hindbrain
o Medulla
o Pons
o Cerebellum
- Midbrain
o Colliculi
o Substantia nigra

, - Diencephalon  thalamus, hypothalamus and pituary gland

Thalamus  everything passes through

Un humans the forebrain has become exceptionally big.
- Subcortical structures
o Basal ganglia
 Caudate nucleus
 Putamen
 Globus pallidus
 Subthalamic nucleus (STN)
 Substantia nigra
o Limbic system
 Cingulate  part of cortex
 Hippocampus
 Hypothalamus
 Amygdala


Grey matter  cell bodies
White matter  connections

Basal ganglia circuits
- Motor circuit
- Associative circuit  learning
- Reward circuit

Telencephalon  cortical
- Frontal lobes  movement, attention, reward, short-term memory,
planning, impulse control
- Parietal lobs  sensory integration, association processes, language
functions, spatial processing, sense of touch, some visual processes
- Occipital lobes  visual areas
- Temporal lobes  memory, emotion association, primary auditory
areas, some visual

Functional asymmetries
- Language  left-lateralized
- Global perception  right lateralized
- Local perception  left lateralized

Gyrus: bumps in the wrinkels
Sulcus: grooves in the wrinkels
 recognizable landmarks

Open spaces in brain imaging  ventricles of the brain
- lateral ventricles
- 3rd ventricle
- Aqueduct

, - 4th ventricle
- Central canal

Ventricular system and CSF

CSF runs through the
- Ventricles,
- Subarachnoid space
- Venous sinus

And is created in the
- Choroid plexus
- Ependymal cells

Membranes. Covering the brain and spinal cord
- Dura mater
- Arachnoid
- Pia mater

Naming conventions
- Brodmann areas  histological: set up based on the kind of cells in
the areas, NOT what they are doing
- Functional names  assumes one function per area
- Relative locations  directional planes
- Coordinate systems  most precise!
o X, y and z coordinates
o MNI coordinates  based on “standard” brain




Brain development & plasticity

Cortical thickness relates to cognitive functioning according to studies

Cell development
- Dendritic spine formation  sensitivity
- Neurogenesis  allows new cells to come into existence into the
living brain, but only in specific places

, - Apoptosis  pre-programmed cell-death (pruning)

Changes in healthy aging
- Cortical thinning/ atrophy
- Neuronal loss
- White matter lesions
- Inflammations
- Decrease in cerebral blood flow
- Beta-amyloid plaques

Fjell et al (2015)  lot of change in young years compared to older

Stronger activation in older people compared to younger people 
Gazzeleu et al (2005)

Cabeza et al (2004)  reduced occipital activity and stronger parietal
and prefrontal activity for elderly

Bangert & Schlaug (2006)  comparing string players (highly
developed motor skills in one hand) to pianists (two hands)

Functional pathways
- Visual
- Auditory
- Somatosensory
- Motor

Functional plasticity  function can reorganize dynamically (visual
cortex is activated in blind individuals when reading braille)

Brain damage
- Normal aging
- Vascular  stroke
- Trauma
- Tumors
- Developmental disorders
- Toxicity
- Infections

Most common occlusion site  middle cerebral artery

Stroke:
- Ischemic: lack of oxygen
- Hemorrhagic: “leak”

Many TIAs  white matter leasions

Trauma