Understanding the neurobiological foundations of cognitive functions.
How the brain enables the mind.
It is at the intersection of cognitive science and neuroscience.
Cognitive science - a historical overview
Neuroscience - a historical overview
Cognitive neuroscience
Methods
Associationism - Associations
Ebbinghaus, Weber, Fechner, Thorndike
Behaviorism – Learning
Watson, Skinner
Cognitivism – Mental Models
Miller, Chomsky, Simon
Computational Science
Information theory
Mind as a computer
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Egypt:
18th century BC Edwin Smith Surgical Papyrus
First documented aphasia case
Ancient Greece:
Hippocrates (460-370 BC)
Importance of the brain
“Men ought to know that from the brain, and from the brain only, arise our pleasures, joy, laughter and jests, as well as our sorrows, pains, griefs, and tears.”
Middle Age
Ventricular theory
Sensory information is processed in the brain.
Realized by the ventricles in the brain – the soul cannot be material – ventricles are ”empty” spaces in the brain.
Three parts:
Collecting thoughts
Organizing thoughts
Storing certain thoughts
Age of Enlightenment
René Descartes
Dualism: body (brain) and soul are separate entities; ventricles are the place of the soul
Connection with the body: pineal gland
Phrenology
Franz Joseph Gall(19th century)
Mental functions (cca. 35) can be linked to the brain
Specific functions are linked to specific brain areas.
Functions utilized more lead to an enlargement of the brain area related to that function – bumps on the skull
Pseudoscience – no experiments
The Cell
Second part of 19th century
Physiological studies
Santiago Ramón y Cajal
Neurons are discrete entities
Communication between neurons
Action potentials
Synapses
Neurotransmitters
Functional localization
Wilder Penfield (neurosurgeon, 1891-1976)
Mapping the cortex
Electric stimulation before surgery
'70's
Neuroscientists started to build models
Psychologists began to consider the brain
Bridging the gap
Different operating and analytical levels
Molecule, cell, network, etc.
Big push in the '80s: "meteoric rise of brain imaging" (Gazzaniga, 2002)
Brain imaging procedures (PET, fMRI)
methods of experimental psychology + models of cognitive science + neurobiology
Convergence
Combining results from several experimental paradigms to illuminate a theoretical concept
Series of experiments
Meta-analyses
Complementarity
Complementary methods
Neuroscience techniques differ in their spatial and temporal resolution
Spatial resolution:
Ranges from 1m to 0.1 μm
Scalp ERPs, TMS, MEG, PET, Human optical, fMRI, Human intracranial ERPs, Animal optical techniques, Single-unit recording, Patch-clamp recording are included.
Temporal resolution:
Ranges from 1 ms to 1 yr
EEG, Drug manipulations, Lesion (human), Gyrus, Voxel (fMRI), Lesion (animal), Cortical column, Neuron, Axon (diameter), Synapse are included.
Brain perturbation approach
Measure task performance after perturbation of the brain to understand cognition
Neuromonitoring approach
Manipulate cognitive process and measure neural variable in the brain to understand cognition
Stroke, trauma, diseases - neurology
Limitations
Many uncontrolled factors can lead to leasions
Variability: lesions and brain areas related to cognitive functions
Pharmacological studies:
Chronic drug use/abuse (e.g., cocaine use)
Targeted research (e.g., nicotine effects)
Brain stimulation - (ir)reversible lesions
Intracranial stimulation (electrodes)
Extracranial stimulation (e.g., transcranial magnetic stimulation (TMS), transcranial direct stimulation (tDCS)
Measuring neural activity during cognitive processing
Direct electrophysiological recording from neurons
Single unit recording
Electroencephalography (EEG)
Event-related potentials (ERPs)
Computer tomography (CT)
3D images about the head
Slices – tomograms (tomo – cut, slice)
Magnetic resonance imaging (MRI)
Magnetic: strong magnetic field – protons of hydrogen atoms become aligned with the magnetic field of the scanner
Resonance: radio wave excitation
Positron emission tomography (PET) imaging
Functional magnetic resonance imaging (fMRI)
BOLD (blood oxygenation level-dependent) signal
Oxyhemoglobin
Deoxyhemoglobin
PET/fMRI experiment design
Unilateral visual information processing