The Brain
A command and control center for
our simultaneous multiple constraint
satisfying machine.
Outline
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Staying alive and maintaining Homeostasis
Perception
Motivation and Effort
Emotions & Habits
Decision Making
Movement and Procedural Learning
Memory
Language
Methods for studying the brain
Having a Brain is Evolutionarily
Conserved
The Brain Stem
(staying alive)
Thalamus
Structure: X-Ray View
What and where pathways of vision
Structure: X-Ray View
Hypothalamus: Homeostasis meets
Consciousness
(Sleep and Hunger)
See Kens lecture 8/29
slide 18
Drive to eat:
HPA (hypothalamus-pituitary- adrenal) axis
(stress), Dopamine (motivation), Memory (
food location), Cannabinoids (munchies)
Motivation and Allocation of Effort
Motivation and Allocation of Effort
Motivation Pathways
Two Dopamine (DA) pathways drive a variety
of activity:
• Emotions
• Habits
• Decisions
• Risk assessment
• Movement
• Memory
Emotions & Habits
Orbital frontal cortex (OFC)
Motivation Pathways
Two Dopamine (DA) pathways drive a variety
of activity:
• Emotions
• Habits
• Decisions
• Risk assessment
• Movement
• Memory
Decision Making and Risk
Case Study: Phineas Gage
Motivation Pathways
Two Dopamine (DA) pathways drive a variety
of activity:
• Emotions
• Habits
• Decisions
• Risk assessment
• Movement
• Memory
Movement
• Representation
- Where is the body?
• Planning
- Where and how should it all be moved?
• Execution
- Just do it. Fixed action patterns vs Planning
• Feedback
- Do it correctly and do it better next time.
Body representation: Homunculus Map of
Human Cortex
Homunculus Map of Human Cortex
Motor Planning
Parietal Cortex
Basal Ganglia: Procedural Learning and
motor Output
Seger & Miller (2010)
22
Cerebellum and Prediction
Errors
Thalamus
Apraxias
• Difficulty in carrying out purposeful
movements without the loss of muscle
strength or coordination
– Disconnection between primary and nonprimary motor areas
– Able to carry out each part of a complex
movement, but disruption lies in
coordination of the movements
Motivation Pathways
Two Dopamine (DA) pathways drive a variety
of activity:
• Emotions
• Habits
• Decisions
• Risk assessment
• Movement
• Memory
Hippocampus: Explicit Memory
Binding problem
• Hippocampus seems to do it but how?
Place cells in hippocampus
HM: Life without a Hippocampus
Language: Beyond Dopamine.
Aphasias
• Broca’s Aphasia: disturbance in speech production,
caused by damage to Broca’s area
– Patient video
• Agrammaticism
• Anomia
• Difficulty with articulation
• Wernicke’s Aphasia: disturbance in speech
comprehension, caused by damage to Wernicke’s
area
– Patient video
• Disruption in recognition of spoken words
• Disruption in comprehension of the meaning of words
• Inability to convert thought into words
Aphasias
Summary of neuro systems
• Multiple systems in the brain.
• Simultaneous interactions between systems.
• Relays between areas that process
information and areas that integrate that
information.
• Behavior is the result of functional
specialization of processing in a distributed
network.
• The work is complicated and ongoing
Methods for studying the brain
• Single-cell and population recordings
– Animal studies
– Surgical patient studies
– EEG
• Stimulation
– Animal studies
– Surgical patient studies
– TMS, tDCS
• Damage
– Animal lesions
– Human injury
– Human surgical lesions
• Neuroimaging
– Structural analysis, fMRI, DTI, MEG
• Genetics
• Electroencephalogram (EEG) recording
– Electrodes are placed on the surface of the
scalp and record/amplify the electrical
signal given off by the brain
– Event Related Potentials (ERPs) are used
to study how the brain responds to different
stimuli or events
CT scan
MRI scan
Functional Magnetic Resonance Imagingin (fMRI)
– Measures changes in blood-oxygenlevel-dependent (BOLD) activation
– Areas of the brain that are engaged
more in a task, require oxygen rich
blood
– Result show a very small but highly
significant percent change in BOLD
activation (the entire brain is active all
the time)
Connectivity measures
Functional connectivity – uses resting-state fMRI data to chart
cortical regions with temporal synchrony (correlation of
activation patterns)
Structural connectivity –
measures the movement of
water molecules to chart the
white matter tracts
(visualizing anatomy)
Diffusion Tensor Imaging (DTI)
Diffusion Spectrum Imaging (DSI)
Brain Review- concepts
-cephalization
-CNS vs peripheral
-sensory input and motor
output
-homunculus (topography
and distortions of input)
-Dopamine and
motivation (prediction)
-contralateral innervation
-neurons!
-all or none (rate coding)
-doctrine of nerve
energies
-Structure and function
are all tied up together.
Brain areas to know
• Hindbrain (brainstem)
• Hypothalamus!!
– Pituitary gland, sleep,
motivations (eating)
• Thalamus (relay)
• Limbic (emotional
valence)
• Cortex (lobes)
• Occipital
(what/where/visual hemi
fields on opposite sides)
• Language (left lateralized)
• Somatosensory vs motor
planning (homunculus)
• Parietal (where)
• Temporal (what)
• Executive control (frontal
lobe)
• Hippocampus (explicit
memory & place cells)
• Basal ganglia (procedural
memory)
Damage- structure related to function
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Split brain –corpus callosum
Phineas gage – frontal damage
HM - hippocampus
Aphaisas brocca and wernikes –language
circuits brocca(output) wernikes (input)
Apraxias –motor planning and body sensation
disconnect
Visual agnosias – inability to see something
(prosapagnosia -face blindness)
Hypothalamus –FAT rats
Autism – failure of connections to form?
Brain Structure
What does the homunculus tell us?
• Localization of motor
and sensory function
• Topographical
organization
• Cortical representation
related to function not
mass
Split Brain