The MindBody issue

1
Outline

• PART I
• The Mind-Body issue
• Defining the domain of Cognitive Neuroscience
• Organization of the nervous system.
• Cerebral cortex and other important structures.
• Demonstrating brain asymmetries.
• PART II
• Research methods in cognitive psychology
• Visualizing brain structures and functions

2
The mind-body issue
The Transposed Heads A Legend of India by
Thomas Mann (1941) Sita marries a man but is
attracted by another. The two desperate men
behead themselves. Sita then prays desperately
the goddess Kali to bring them back to life. Kali
grants Sitas wish and allow her to reattach
their heads to their body. In the rush to get
them back to life, Sita switches their heads,
attaching them to the wrong bodies. Sita faces a
terrible dilemma who is who?

• Is the mind located somewhere in the body?
• If yes, what are the biological bases of our
  cognitive skills?
• Cognitive psychologists are interested in
  answering these questions,because it is important
  for many fundamental purposes to know the
  physical constraints of our cognition.
• Theres a long standing hypothesis that, if
  there has to be a site in the body for our mind,
  it is the brain.
• Even though this claim stands since Hippocrates
  (400 b.c.), only in the 19th century scientists
  became systematically interested in localizing
  cognitive functions in specific brain area.

3
Defining the domain

• Cognitive neuroscience is the field of study
  linking the brain structures to cognitive
  processes and, eventually, to behavior.
• The founder of this branch of cognition,
  Gazzaniga, claims that the nervous system is the
  basis for our ability to perceive, adapt to, and
  interact with the world around us.

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The neuron

• Neurons are the cells of the brain. They are the
  basic functional and structural units of the
  nervous system. The neuron main task is to
  receive electrical signal from other neurons and
  to trasmit it, under particular conditions, to
  other neurons
• The main parts of the neuron are
• the Dendrites, that carry the signal in the
  cell
• the Soma, the cellular body, that is assumed to
  integrate and process information from the
  stimulated dendrites
• the Axon, usually one for neuron, carries out
  the processed information for the next step of
  the given neural pathway

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Neuronal communication

• Within a neuron the nature of signal
  transmission is electrical. The Action Potential
  propagates in the dendrites and, if it reaches a
  threshold, from the body to the axon.
• Basic processing in the brain is guaranteed by
  communication between neurons. The functional
  unit for this comunication is the synapse.
• In the synapse, the pre-synatpic terminals come
  very near the dendritic spine. The axons action
  potential triggers the release of chemical
  substances called neurotransmitters.
• Once released in the synaptic junction,
  transmitters thatreach specific post/synaptic
  receptors will eventually determine the
  so-called post-synaptic potential
  (excitatory,EPSP, or inhibitory, IPSP).
• Different types of neurons organized in complex
  networks provide the substrate for the cognitive
  modules in the brain

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Neurotransmitters

• Neurotransmitters are chemical messengers for
  transmission of information between neurons.
• There are about 50 substances that the brain
  uses as transmitters. They can be assigned to
  three main categories
• Monoamine neurotransmitters, synthesized in the
  nervous system through enzymatic actions on
  aminoacids (e.g., acetylcholine, dopamine,
  serotonin)
• Aminoacids neurotransmitters, used with no
  transformation (e.g., gamma-aminobutyric acid,
  GABA)
• Neuropeptides, which are chains of two or
  aminoacids.
• The reason for such a big variety of
  transmitters is that they are associated to
  different actions (some are inhibitory, some
  excitatory) and that their action is specific to
  specific networks and/or cognitive functions
  (e.g. Dopamine and Parkinson desease).

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Organization of the nervous system
Main focus for cognition
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Cerebral cortex and other structures supporting
cognition

• The central nervous system (CNS) is split into
  three main divisions

9
The Central Nervous System
just to mention a few structures
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Cortical specializations

• The cerebral cortex consists of several aras
  distinct by location and by function.
• The first big specialization occurs between the
  two hemispheres
• The left emisphere is specialized for language.
  Damages to the left side of the brain result in
  speech impairment of various nature.
• The right hemisphere is better suited for visual
  and spatial complex abilities
• Within each hemisphere, the lobes are
  quasi-specialized areas of the cortex, but there
  is a finer specialization within each lobe.
• We will treat the details of cerebral
  localization of cognitive skills when well deal
  with specific topics of cognition. Now let us see
  if the two emispheres are actually specialized

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CLASS EXPERIMENT finding brain asymmetries

• The task of one voluntary will be that of
  cathegorizing stimuli as quick as possible.
  Stimuli will be shapes and words and will appear
  either to the left or to the right of fixation.
• Responses will be given by pressing one of two
  buttons on your right and your left side.
• The experiment will last for 160 trials and
  feedback for correct/incorrect responses will be
  provided.

CogLab experiment Brain Asymmetries