Emotions If only it were as simple as the diagrams below…

1. EmotionsIf only it were as simple as the diagrams below…

2. Perspectives to Consider in Understanding Emotionality…to begin: • Broca (1878) and “Le Grande Lobe Limbique” (Grand Limbic Lobe) – this is a a reference strictly to anatomical organization. • Papez (1930) – Linked the structures comprising the “Limbic System” as having a role in emotions. • Paul McLean (1949) expanded on the Papez Circuit in the article “Psychosomatic Brain and the Viscera.” (see ANGEL site for the original article).

3. Papez Circuit (circa 1930) From: Bear et al., 2007

4. McLean’s Conceptual Model Neocortex - Thought (including planning, language, logic & will, awareness) Limbic System - Emotion (feelings, relationship/nurturing, images and dreams, play) Reptilian Brain - Instinct (survival, breathing/swallowing/heartbeat, startle response) See ANGEL site for McLean’s original 1949 article Diagram from: www.sustainablesonoma.org/.../threebrains.html

5. From McLean (1949)

6. Another point to consider: • Attributing Function to the Structural Arrangement of the Limbic System (easier said than done). Numerous studies led to paradoxical findings making definitions of the limbic system confusing. The following brain areas are most commonly regarded as components of the Limbic System because they appear to play a role in one or more aspects of emotion (e.g. visceral brain, emotional memory, neuroendocrine control): • Cingulate Gyrus • Hippocampus • Parahippocampus Gyrus • Amygdala • Septal Nuclei • Thalamus • Hypothalamus

7. …More Points to Consider: • What about the role of the Basal Ganglia (e.g., Nucleus Accumbens or Ventral Striatum)? • What about the brainstem structures? • What about structures that are neurally and chemically linked to the traditional “Limbic System”? Morgane, Caller & Mokler (2005) emphasize the importance of a limbic forebrain/limbic midbrain complex.

8. From: Morgane, Caller & Mokler (2005)

9. …Even More Points to Consider: • The Limbic System is really a “Non Limbic System” because specific function cannot be assigned to specific neural pathways (Robert L. Isaacson, 1992 & 2007), in addition to the disparity in identifying system structures. Both structural and functional aspects of the “Limbic System” concepts are too comprehensive and too vague to serve as scientific explanation or as a useful conceptual model, therefore the term should be abandoned (note: a new book entitled The Non Limbic System by RL Isaacson is in preparation). There is a “fuzziness” in the brain systems that can never be avoided -- the neural networks overlap and interact (and are densely interconnected) such that they cannot be subsumed under sensory OR motor systems. Localization of function exists in a general sense only and beyond this, everything is not as neat and tidy as is generally thought (this is an important perspective to remember to open one’s mind about how the brain works). • Finally, the argument is really not about whether the Limbic System exists or does not exist, but in the use of precise terminology and a viable conceptual model.

10. How Might this Issue Be Resolved? Rolf Kottler (2003) suggests these guidelines: • Establish the precise structure & function that “limbic” refers to in order to reduce confusion (e.g., be specific about what is meant by “limbic dysfunction”). • Replace the term “limbic” with a more precise term (e.g., rather than saying “limbic thalamus,” state it as the “anterior nucleus of the thalamus” or even more specifically such as “anteromedial” thalamic nucleus). • Avoid drawing upon “Limbic System” concepts for building new hypotheses because it builds on an already shaking conceptual framework. • Be aware that “Limbic System” concepts imply structure and function, which is useful in highlighting unanswered questions about the mechanism of emotion, consciousness or the self. BUT, this is NOT a scientific explanation because the details still need to be worked out.

11. Having said all this, lets get back to emotions with the term “Limbic System” in absentia: How are emotions classified? Behavioral States Motivational States Moods &Background Emotions Emotion Systems+ Basic Emotions Social Emotions* Approach Reward Depression Seeking Happiness Pride Withdrawal Punishment Anxiety Panic Fear Embarrassment Thirst Mania Anger Rage Quilt Hunger Cheerfulness Fear Disgust Shame Pain Contentment Sadness Maternal love Craving Worry (Surprise) Sexual love (Contempt) Infatuation Admiration Jealousy Emotions are situated in a continuum of response classifications. The more primitive classes, towards the left, pertain to emotional reactions, whereas the more complex classes, towards the right, pertain to social communication. Typically, researchers working on animals have adopted a scheme relying on reward and punishment, whereas research in humans has often used so-called ‘basic’ emotions, and psychiatric or social psychological studies have utilized even more complex constructs such as the ‘social’ emotions*, whose neural underpinnings are at present very poorly understood. Reproduced with permission from Adolphs’s 2002 article that appeared in Behavioral & Cognitive Neuroscience Review. From: Ralph Adolphs (2002), Neural Systems for Recognizing Emotions + Panksepp J: Affective Neuroscience. New York: Oxford UniversityPress; 1998.

12. Two components are necessary for the recognition of basic emotions: • Perceptual Processing (taking in all the salient pieces of information from the stimulus) • Recognition of the Emotional Meaning of the Stimulus, that is, linking the stimulus with previously learned information which includes • the emotional response from one’s knowledge base, • the “word” or lexical label, • and knowledge about the motor “representation” that is needed to produce the emotion (i.e. the motor response of a smile produces feelings/recognition of the emotion happiness). From: Adolphs (2002), Neural Systems for Recognizing Emotions

13. What Brain Structures are Involved in Recognizing Emotion From Facial Expression? A Feed-Forward & Feedback Sweep of Information Processing • Within ~100 msec the primary visual cortex and secondary visual cortical areas (e.g., superior temporal region) extract information from the facial expression and determine if it is communicating emotions. • Amygdala and Orbitofrontal cortices take this original coarse perception and refine it via a feedback process: - it allocates attention to certain features - it triggers associated knowledge via projection to other neocortical areas and to the hippocampus (retrieves conceptual knowledge about the emotional). - it generates an emotional response in the person via connections to motor structures, hypothalamus and brainstem nuclei (where emotional response is generated). This mechanism, via a feed-forward mechanism, can induce… - the emotional state in the person perceiving the stimulus via a simulated experience through activation of the right somatosensory cortices. (But this can also occur without direct stimulation from motor regions). Adolphs, 2002

14. Sweep of Information Processing for Emotional Facial Expression Adolphs, 2002

15. Neural Basis of Other Stimuli • Sounds of disgust in language and neural links are difficult to track, making this type of prosody tracking a challenge (note: disgust in facial expressions is a common stimulus). • Prosody depends on right hemisphere BUT also on multiple structures distributed between both left and right hemispheres between frontal (right inferior) and parietal (right posterior) lobes as well as left frontal. The role of the amygdala is unclear for prosody. (note: role of amygdala for other affective sounds is clear). • Processing emotional music that results in “shivers down the spine” activates ventral striatum, amydgala and orbitofronal cortex (categorization of this emotional response is uncertain). • The neural basis of fear is well delineated (see next slide). Adolphs, 2002

16. Associative Learning (Fear Response) Before Training – a transient orienting response is induced to the sound Training – sound is paired with the shock After Training – placement in the box induces freezing when the sound is present. What are the neural networks associated with fear…? From: Squire et al., 2003

17. , 1995) Fear Conditioning (LeDoux, 1995) From: Squire et al., 2003

18. Amygdala & Stress Response From: Bear et al., 2007

19. Amygdala & Enhancement of Memory From: Bear et al., 2007

20. Hippocampus & Stress Response Hippocampus has an inhibitory effect on CRF release. As the hippocampal cells die, its capacity to turn off CRF (and subsequently cortisol) decreases. From: Bear et al., 2007

21. We know a few things about emotions… • Social Phobia is related to an acute capacity to process facial information. • Right Ventromedial Prefrontal cortex is capable of discriminating between fear and happiness with 120 msec of stimulus exposure. • Lesions of the right ventral primary and secondary somatosensory cortices impair recognition of emotions from visual stimuli. • Facial expressions of disgust are processed in the insular cortex, an area closely linked to descending control of the viscera. • Damage to basal ganglia interfere with the facial perceptions of disgust (note: occurs in OCD, Parkinson’s Disease, and Huntington’s Disease). • Chronic stress destroys the hippocampal neurons resulting in smaller size. • Overall, very little is known about social emotions, a great deal is known about fear (and anxiety to some degree) as it relates to behavioral and motivational states, and quite a bit is known about approach (behavioral state) and reward (motivational state). • Understanding emotions is one of the hottest fields in Behavioral Neuroscience and wide open for discovery.