Lecture 2 Flashcards
OG Localization of function
Localized function is true, but areas aren’t isolated.
-functions are properties of integrated systems and not isolated brain areas.
Two pioneering localization techniques
- Stimulating Cortical areas to suggest
- ablating them to prove. reveals functions of region by behavioural or mental capacities that are lost from the ablation.
Early ablation studies
Decorticates (cerebral cortex removed cats) still exhibited emotional arousal
emotions thought to be higher order function and therefore was surprising.
Basis of James’ peripheral feedback theory
James-Lange Theory
Physiology ~ Appraisal
Emotional experienced in response to physiological changes in body.
“My heart is pointing, so i must be afraid”
How we feel leads to what we think
Bard’s early ablation studies
- emotions of decorticates were not normal.
- demonstrated improperly focused “sham rage”. Led Cannon-Bard to suggest that HYP is centre of emo brain
Cannon’s 5 crits of J-L Theory
- total separation of viscera from CNS does not alter emotional behaviour
- Same visceral changes occur in very different emo states and in non-emo states
- viscera relatively insensitive structures
- visceral changes are too slow to be source of emotional feeling
- artificial induction of visceral changes typical of strong emotions does not produce them
Hypothalamus
sits @ base of forebrain
forms interfact b/w psychologically sophisticated forebrain and more primitive lower areas
Known to regulate ANS
Cannon-Bard Theory (Part 1)
Appraisal ~ Physiology
Emotions occur independent of emotional expression
“I feel afraid, so my heart pounds”
Cannon-Bard Theory (Part 2)
HYP receives sensory inputs from thalamus at same time as the cognitive aspect from the neocortex.
-Appraisal and physiologic response happens simultaneously and distinctly of each other
This activates body to produce automatic and behavioural responses characteristic of emotional rxn’s
eliminates cortex from events leading to emo response
Limitations of J-L and C-B theories
(not exactly opposites of eachother)
J-L: assumes there is unique physiological signature to each emotion
C-B: physiological responses generated so quickly, unlikely that we could have perceived emotion first
Papez circuit (part 1)
helps explain subjective experience of emotion
Sensory experiences take distinct pathways: “thought” & “feeling”
Introduced hippocampus
Papez Circuit streams
- Thought Stream: Thalamus to cortex reflected by cingulate cortex back to stream of thought.
- Feeling Stream: Thalamus to hypothalamus to direct involuntary hormonal and autonomic hormones
Papez circuit crits
doesn’t link thought pathway with cognitive appraisal of emotions
doesn’t explain how it is produced.
Kluver-Bucy syndrome
provided evidence of critical role of temporal love areas in emotion
-ablating temporal lobe resulted in “psychic blindness”
Psychic Blindness
ablating temp lobe results in inability to apprehend motivational or emotional significance of stimuli or events in their environment. Even if they are capable of processing sensory properties of stimuli
- can’t put sensory pieces together to make sense of them.
- results in blunting of emotional rxns associated with fear or novel objects
