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psych 100 review summary.doc

Course Code
PSYC 100
Daniel Levitin

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Phineas Gage, a construction foreman, hit by an iron rod
Iron rod enters from left cheek, pierces the base of the skull, traverses the front of the brain and exits
through the top of the head.
Gage is pronounced cured in less than two months.
But….“Gage is no longer Gage” .
Brain includes personal and social dimensions of reasoning.
Some part of the value system remains but is unconnected to real-life situations.
Intact attention, perception, memory, language, intelligence. “Dissociation”.
Two camps of thought:
oIf brain produces the mind, it does it as a whole and not as collection of parts with special functions
oBrain has specialized parts that generate separate mind functions.
oBrain an aggregate of many organs, each having a specific physiological faculty e.g. Benevolence and
oDamasio: “What determines the contribution of a given brain unit to the operation of the system to which it
belongs is not just the structure of the unit but also its place in the system.
Can Gage be held responsible for his behavior?
oWilliam James: constant flow, constant change.
oIn the awareness there is a succession of perceptions of the present.
Psychical Responses to Stimulation and Discharge:
oCerebral cortex has folds. Only about 35% on the surface.
oNeurons and ganglion cells are responsive to electrical stimulation (as well as chemical stimulation—
oBehavioral functioning of a brain area is revealed due to conductivity (Sensory or motor areas-
oPenfield and Roberts first used this electrical stimulation technique to examine the temporal lobe as
treatment for epilepsy

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oThe goal of the electrical exploration of the temporal lobe was to find the epileptic locus and surgically
remove it. Stimulation of the epileptogenic focus induces a partial seizure.
oHughlings Jackson was the first to observe that patients undergoing electrical brain stimulation experienced
a state of reminiscence or double-dissociations which he calles “dreamy states”.
oDouble- dissociations: a state where the patients re-live past experiences but are still aware of their present
oThere are two types of physical responses that are obtained from electrical stimulation and each can be
mapped to a specific brain region
Interpretative: “Déjà vu” phenomenon (false memories)
False interpretations (called illusions).
Stereotyped Symptoms: judgments of familiarity, strangeness, distance, intensity, loneliness fear.
The subject becomes aware of the present and re-interprets it.
Experiental: Characterized by flash-backs that have strong visual and auditory components. Not still pictures.
Consciousness is re-visited.
Double-consciousness (patients re-live past streams while being aware of the present)
They occur in an all or none pattern (don’t go backward, are not mixed with other experiences and stop as suddenly
as they started upon removal of the stimulation)
The same experience can be elicited by re-stimulating the same area. Lower threshold though.
Both of these types of responses argue for the existence of a permanent recording of the stream of
consciousness, which must be preserved in a specialized mechanism that allows for later recall.
These responses are specific to the temporal lobe
Question: How come intelligence is intact despite surgical removal of a major portion of the brain?
Learning vs. Perception
Theory of cell assemblies attempts to bring together anatomical, physiological and behavioral data to
understand the integrative function of the whole brain.
oAs opposed to learning, not dependent on excitation of a particular set of neurons.
oLearning is a changed pattern of conduction in the brain that results from experience and makes a change of
response potential.
oIf the pattern of conduction persists it is memory. Hence learning is a localized effect.
oNot true for perception e.g. different angles of familiar objects.

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oLashley-Kohler: what matters in perception is the Gestalt, the form or pattern of stimulation.
oBut how can variable perception excite a specific response? Hologram
oSet (attention, attitude, expectancy) is brain activity that is free from sensory control (Hilgard and Marquis)
oLashley showed that direct connections (of learning) do not occur. For e.g. (Figure 14.2) connection
between the visual and motor cortex.
oLorent de Neo showed that cortex is mostly composed of very complex closed or re-entrant pathways
oAccording to Hebb “set” occurs when two stimuli are presented one after the other and the response to the
second is controlled or modified by the first.
oThe cell assembly theory explains set: The mechanism of thought is a recurrent neural loop that received
sensory input from another loop but that can be maintained in the absence of sensory information.
oBrodgen’s experiment: dogs can form purely sensory associations.
oHebb thought that self-re-exciting system must have a number of circuits because of fatigue and for mass
oBut…this theory does not hold for visual perception. A different cell-assembly would be required for each
possible stimulus.
oPerhaps cell assemblies formed for representation of fundamental parts. However, for unfamiliar objects
new cell-assemblies would have to be created.
Blind people
Chimpanzees raised in the dark
Head of a Chimpanzee
oEffects of environment on intelligence
oImportance of period of growth (Hymovitch)
oExposure to visual stimuli (Hymovitch)
Experiments on remote-viewing trials.
Remote viewing: the ability of certain individuals to access and describe, by mental processes, remote
geographical sites blocked from ordinary perception by reason of distance and shielding
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