Limbic System

Question 1

Cingulate gyr

Answer 1

Receptive area for experiencing emotion

Question 2

Limbic system

Answer 2

• those areas of cortex that are NOT isocortical (six-layered)
  namely nursing and maternal care, audiovocal communications – vital for maintaining maternal–offspring contact – and play
• emotions involve relatively primitive circuits that are conserved throughout mammalian evolution seems right on target.
• cognitive processes might involve other circuits, and might function relatively independent of emotional circuits, at least in some circumstances, also seems correct

Question 3

Hypothalamus

Answer 3

Essential for expression of emotion, requires connections to the cortex

Question 4

The orbital part of the frontal cortex*

Answer 4

Connections with anterior insula, amygdala, hippocampus, ventral striatum, sensory projection pathways

Question 5

Ventral striatum*

Answer 5

• Relates to emotional motor expression
• The main output from the ventral striatum is to the ventral globus pallidus and thence to the thalamus, which then projects back to the frontal cortex
• Reward and motivation

Question 6

basal ganglia

Answer 6

major outputs from the limbic system go here

Question 7

shortcomings

Answer 7

• damage to the hippocampus, the centerpiece of the limbic system, led to severe deficits in a distinctly cognitive function, long-term memory . This was incompatible with the original idea that the primitive architecture of the limbic system, and especially of the hippocampus, was poorly suited to participate in cognitive functions
• the equivalent of mammalian neocortex is present, though rudimentary, in nonmammallian vertebrates (see Nauta & Karten 1970). As a result, the old/new cortex distinction broke down, challenging the evolutionary basis of the assignment of emotion to the limbic system and cognition to the neocortex (

Question 8

auditory fear conditioning

Answer 8

• neutral stimulus [a conditioned stimulus (CS)] can acquire affective properties on repeated temporal pairings with a biologically significant event [the unconditioned stimulus (US)].
• conditioned fear is mediated by the transmission of information about the CS and US to the amygdala, and the control of fear reactions by way of output projections from the amygdala to the behavioral, autonomic, and endocrine response control systems located in the brainstem

Question 9

Lateral Amygdala

Answer 9

• Auditory and sensory inputs from thalamus/auditory cortex terminate in the LA, damage to the LA interferes with fear conditioning to sounds
• CS is mediated by either pathway but thalamus to LA is faster
• The convergence of the US and CS occurs in the LA
• CS elicited responses induces plasticity
• US also has thalamus and cortex inputs
• Nociceptive stimuli

Question 10

Accessory Basal Amygdala

Answer 10

• Receives inputs from the hippocampus (context), may be modified by US inputs to the AB
• context-US convergence

Question 11

Central Nuclei AMygdala

Answer 11

• Nociceptive stimuli
• Projects to brainstem areas that control expression of fear responses
• Damage to CE interferes with expression of conditioned fear responses
• Damage to lateral hypothalamus output affects blood pressure
• Damage to periaqueductal gray interferes with freezing

Question 12

Projections within the Amygdala

Answer 12

• LA projects to B, AB, CE . . . . . B and AB also project to CE
• lesions of B and AB have no effect on simple fear conditioning to a tone

Question 13

WHat does contextual fear require? WHat amygdala structures does it project to?

Answer 13

• Contextual fear conditioning requires hippocampus and amygdala
• Ventral hippocampus projects to B and AB amygdala
• Damage to these areas interfere with contextual conditioning