Lecture 3: The Neural Basis of Cognition

capgras syndrome

• patients can recognize loved ones, but think they are imposters

• emotional appraisal is disrupted

• linked to abnormalities in the amygdala & prefrontal cortex

• simple processing involves multiple regions

Normal facial recognition involves what 2 systems?

1. cognitive appraisal

2. emotional appraisal

What does damage to the amygdala result?

lack of emotional response

amygdala

emotional processing center/evaluator: feelings of familiarity, memory for emotional events, & emotional decision-making

basic parts of a neuron

1. dendrites

2. cell body

3. axon

dendrites

detect incoming signals from other neurons

cell body

contains the nucleus & cellular machinery

axon

transmits signals to other neurons

glia

• guide development of nervous system

• repair damage in the nervous system

• control nutrient flow to neurons

• electrical insulation

What are the 3 main structures in the human brain?

1. hindbrain

2. midbrain

3. forebrain

hindbrain

• top of the spinal cord

• key life functions

• cerebellum - largest region of the hindbrain

• includes the pons & medulla

midbrain

• coordinate precise eye movement

• relay auditory information: ears → forebrain

• regulate pain experience

forebrain

• surrounds the midbrain & most of the hindbrain

• includes the cortex, 4 lobes, & subcortical structures

  • cortex - outer surface of the forebrain (80% of the brain)

• divided into 2 cerebral hemispheres by the longitudinal fissure

subcortical structures

1. thalamus

2. hypothalamus

3. limbic system: amygdala & hippocampus

thalamus

sensory relay station

hypothalamus

controls behavior that serve specific biological needs (i.e. eating)

limbic system

1. amygdala

2. hippocampus

amygdala

emotional processing

hippocampus

learning & memory

How is the brain divided?

• roughly symmetrical left & right hemispheres

• contralateral cortical organization

• connected by commissures

contralateral cortical organizatoin

each hemisphere controls the opposite side of the body

commisures

• thick bundles of fiber that carry information

• act as communication between hemispheres

• largest: corpus callosum

split-brain patients

• severed corpus callosum

• last-resort treatment for epilepsy

• limits communication between hemispheres

How does cognitive neuroscience study the brain & the nervous system?

1. neuropsychology

2. neuroimaging

3. electrical recordings

4. manipulation of brain function

neuropsychology

study of the brain’s structures & their relation to function

neuroimaging

1. structural

   • CT

   • MRI

2. functional

   • PET

   • fMRI

3. electrical

   • EEG

CT scans

• x-ray pictures of the brain

• patient is exposed to radiation

• useful in medical system

• ≠ used in research that much anymore

• “computerized axial tomography”

MRI scans

• see fine details & small abnormalities in the brain

• “magnetic resonance imaging”

PET scans

• tracer substance is entered into body (i.e. glucose)

• “positron emission tomography

fMRI scans

• measure blood oxygen levels in the brain

• fusiform face area (FFA)

• parahippocampal place area (PPA)

• guessing with timing

• functional magnetic resonance imaging

electroencephalogram (EEG)

• recording of the electrical communication within neurons

• good with timing

• ≠ great with location (≠ get to hippocampus)

• used to study: broad rhythms (i.e. sleep stages) & event-related potentials (ERPs)

What is the strength & weakness of EEGs?

strength: temporal locating neural activity (good timing)

weakness: bad @ spatially locating neural activity

What is the strength & weakness of fMRIs?

strength: spatially locating neural activity

weakness: bad @ temporally locating neural activity (bad timing)

What is the strength & weakness of MRI scans?

strength: detecting brain structures

weakness: bad with detecting brain activity

How do researchers overcome limitations of neruroimaging techniques?

combining techniques

the cerebral cortex

• outermost layer & largest portion of the human brain

• thin layer of tissue covering the cerebrum

• regions: motor areas, sensory areas, association areas

motor areas

• primary sensory projection areas

• primary motor projection areas

• contralateral control

sensory areas

• somatosensory area

• primary auditory cortex (temporal lobe)

• primary visual cortex

association areas

• 75% of the cerebral cortex

• contain many specialized subregions in which damage can result in:

  • apraxia

  • agnosia

  • unilateral neglect syndrome

  • aphasia

apraxia

problems with initiation/volunteering actions (i.e. waving)

agnosia

problem with recognizing objects

aphasia

• problems with language

• speech ≠ fluent → missing words