Edmund Rolls - Brain and Emotion
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Rolls; Brain and Emotion 1 Prefrontal cortex has undergone great development in primates, and the orbitofrontal cortex is very little developed in rodents, yet is it is one of the major brain areas involved in emotion and motivation and primates including humans.
Rolls; Brain and Emotion 3 A reward is something for which an animal will work. 2
Rolls; Brain and Emotion 3 A punishment is something an animal of will work to escape or avoid. 0
Rolls; Brain and Emotion 4 In classical conditioning, the taste of food (the unconditioned stimulus) might elicit an unconditioned response of salivation, and if the sight of the food is paierd with the taste, then the sight of that food would by learning come to produce salivation, and would become a conditioned stimulus for the conditioned response of salivation. 1
Rolls; Brain and Emotion 4 Pairing the sight of an object with a reward or punishment can lead to stimulus-reinforcement association learning. 0
Rolls; Brain and Emotion 5 Having reward and punishment systems is a solution that evolution has developed to produce appropriate behavior. 1
Rolls; Brain and Emotion 5 Motivational and emotional behavior are the types of behavior in which rewards and punishers operate. 0
Rolls; Brain and Emotion 6 A distinction is that motivated behavior often refers to behavior where the initiating stimulus is an internal, whereas emotional behavior often refers to behavior where the initiating stimulus is an external. 1
Rolls; Brain and Emotion 6 The brain works in motivation and emotion to result in natural selection operating to select genes which optimize our behavior by building into us the appropriate reward and punishment systems. 0
Rolls; Brain and Emotion 23 Responses of hypothalamic neurons in the primate become associated with the sight of food as a result of learning. 17
Rolls; Brain and Emotion 26 There are neurons in the hypothalamus that can respond to the taste (and/or sight) of foods but not of non-foods. 3
Rolls; Brain and Emotion 29 An important food taste that appears to be different from the taste produced by sweet, salt, bitter, or sour is the taste of protein. 3
Rolls; Brain and Emotion 29 The umami taste is common to a diversity of food sources including fish, meats, mushrooms, cheese, and some vegetables such as tomatoes. 0
Rolls; Brain and Emotion 29 Monosodium glutamate (MSG) is an example of umami stimuli. 0
Rolls; Brain and Emotion 96 The primate amygdala contains a population of neurons specialized to respond to faces, and damage to the amygdala can alter the ability to discriminate between different facial expressions. 67
Rolls; Brain and Emotion 96 Connections to the Amygdala 0
Rolls; Brain and Emotion 96 The amygdala is a subcortical region in the anterior part of the temporal lobe. 0
Rolls; Brain and Emotion 96 The amygdala receives massive projections from the overlying temporal lobe cortex. 0
Rolls; Brain and Emotion 96 Inputs to the amygdala come from the inferior temporal visual cortex, the superior temporal auditory cortex, the cortex of the temporal pole, and the cortex of the superior temporal sulcus. 0
Rolls; Brain and Emotion 97 Inputs to the amygdala come from the higher stages of sensory processing in the visual and auditory modalities, and not from early cortical processing areas. 1
Rolls; Brain and Emotion 97 The amygdala also receives inputs that are potentially about primary reinforces, e.g. taste inputs (from the secondary taste cortex, via connections from the orbitofrontal cortex to the amygdala), and somatosensory inputs, potentially about the rewarding or painful aspects of touch (from the somatosensory cortex via the insula). 0
Rolls; Brain and Emotion 97 The amygdala also receives projections from the posterior orbitofrontal cortex. 0
Rolls; Brain and Emotion 98 It has been suggested that the function of backprojections from the amygdala to the cortex include the guidance of information representation and storage in the neocortex, and the recall of the information. 1
Rolls; Brain and Emotion 98 The amygdala has output projections to the entorhinal cortex, which provides a major input to the hippocampus and dentate gyrus, and to the ventral subiculum, which provides a major output to the hippocampus. 0
Rolls; Brain and Emotion 98 Anatomical connections of the amygdala indicate that it is strategically placed to receive highly processed information from the cortex and to influence motor systems, autonomic systems, and some of the cortical areas from which it receives inputs, and other limbic areas. 0
Rolls; Brain and Emotion 112 Orbitofrontal Cortex 14
Rolls; Brain and Emotion 112 Prefrontal cortex is a region of cortex that receives projections from the medial dorsal nucleus of the thalamus and is situated in front of the motor and premotor cortices. 0
Rolls; Brain and Emotion 113 Researchers discovered a taste area in the lateral part of the orbitofrontal cortex and showed that this was secondary taste cortex that receives a major projection from the primary taste cortex. 1
Rolls; Brain and Emotion 118 Convergence of taste and olfactory inputs in the orbitofrontal cortex, forming the representation of flavor. 5
Rolls; Brain and Emotion 118 There is a major visual input to many neurons in the orbitofrontal cortex, and what is represented by these neurons in many cases is the reinforcement association of visual stimuli. 0
Rolls; Brain and Emotion 118 Visual input to the orbitofrontal cortex is from the ventral temporal lobe visual stream concerned with 'what' object is being seen. 0
Rolls; Brain and Emotion 122 Representation of faces in the orbitofrontal cortex. 4
Rolls; Brain and Emotion 124 There is a population of orbitofrontal face-selective neurons that respond in many ways similarly to those in the temporal cortical visual areas. 2
Rolls; Brain and Emotion 124 Orbitofrontal face responsive neurons tend to respond with longer latencies (140-200 ms typically) than temporal lobe neurons (80-100 ms). They also convey information about which face is being seen, by having different responses to different faces. 0
Rolls; Brain and Emotion 124 Some of the orbitofrontal face-selective neurons are responsive to face gesture or movement. 0
Rolls; Brain and Emotion 124 The significance of the face gesture or movement neurons in orbitofrontal cortex is likely to be that faces convey information that is important in social reinforcement, both by conveying face expression and by encoding the identity of an individual, both types of information important in social situations. 0
Rolls; Brain and Emotion 124 Neurophysiological evidence suggests that one function implemented by the orbitofrontal cortex is rapid stimulus-reinforcer association learning, and the correction of these associations when reinforcement contingencies in the environment change. 0
Rolls; Brain and Emotion 124 Orbitofrontal cortex has the necessary representation of primary reinforces, such as taste, and also somatosensory sensory inputs. 0
Rolls; Brain and Emotion 124 Olfactory stimulus can also be conditioned via stimulus-reinforcer association learning in the orbitofrontal cortex, although the learning is slower than for visual. 0
Rolls; Brain and Emotion 124 It is likely that auditory stimuli can be associated with primary reinforcers in the orbitofrontal cortex. 0
Rolls; Brain and Emotion 124 Orbitofrontal cortex neurons which can detect non-reward in a context specific manner, are likely to be used in behavioral extinction and reversal. 0
Rolls; Brain and Emotion 124 It is via the striatal route that the orbitofrontal cortex may directly influence behavior when the orbitofrontal cortex is decoding reinforcement contingencies in the environment. 0
Rolls; Brain and Emotion 126 The amygdala the is concerned with some of the same functions as the orbitofrontal cortex and receives similar inputs. 2
Rolls; Brain and Emotion 126 There is some evidence that the amygdala may function less effectively in the very rapid learning and reversal of stimulus-reinforcement associations, as indicated by the greater difficulty in obtaining reversals from amygdala  neurons. 0
Rolls; Brain and Emotion 127 In primates, the necessity of a very rapid stimulus-reinforcement reevaluation and the development of powerful cortical learning systems may result in the orbitofrontal cortex effectively taking over this aspect of amygdala functions. 1
Rolls; Brain and Emotion 127 Active presynaptic inputs and little postsynaptic activation is the condition for homosynaptic long term depression. 0
Rolls; Brain and Emotion 128 Wisconsin card sorting task (in which cards are to be sorted according to the color, shape, or number of items on each card, depending on whether the examinor says 'right' or 'wrong' to each placement). 1
Rolls; Brain and Emotion 135 Anterior cingulate cortex is connected to the medial orbitofrontal areas, parts of lateral orbitofrontal area 12, the amygdala (which projects strongly to cingulate subgenual area 25), and the temporal pole cortex, and also receives somatosensory inputs from the insula and other somatosensory cortical areas. 7
Rolls; Brain and Emotion 135 Anterior cingulate cortex has output projections to the para-aqueductal gray in the midbrain (which is implicated in pain processing), to the nucleus of the solitary tract and dorsal motor nucleus of the vagus (through which autonomic effects can be elicited), and to the ventral striatum and caudate nucleus (through which behavioral responses could be produced). 0
Rolls; Brain and Emotion 136 The orbitofrontal cortex is involved in the execution of behavioral responses when they are computed by reward or punisher association learning, a function for which the orbitofrontal cortex is specialized. 1
Rolls; Brain and Emotion 137 Orbitofrontal cortex is specialized for reward or punisher association learning in terms of representations of primary (unlearned) reinforcers, and in rapid learning and readjusting associations of stimuli with these primary reinforces. 1
Rolls; Brain and Emotion 143 Adapted value of the cortical strobe provided by the basal magnocellular neurons of the amygdala may be that it facilitates memory storage especially when significant (e.g. reinforcing) environmental stimuli are detected. 6
Rolls; Brain and Emotion 143 Memory storage is likely to be conserved (new memories are less likely to be laid down) when significant environmental stimuli are not present. 0
Rolls; Brain and Emotion 143 Actual memory stored are determined by the act is subset of the thousands of cortical afferents own a strongly activated cortical neuron. 0
Rolls; Brain and Emotion 143 Basal forebrain magnocellular neurons, when activated, increased the probability that a memory will be stored. 0
Rolls; Brain and Emotion 143 Impairment of the normal operation of the basal forebrain magnocellular neurons would be expected to interfere with normal memory, and this interference could contribute to the memory disorder in Alzheimer's disease. 0
Rolls; Brain and Emotion 143 There is typically an onset of the neuronal response at 80-100 ms after the stimulus, followed within 50 ms by the highest firing rate. 0
Rolls; Brain and Emotion 143 When cells are responding fast (e.g. 100 spikes per second) to a visual stimulus. 0
Rolls; Brain and Emotion 143 Source of noradrenergic projection to the neocortex is the locus coeruleus in the pons.    A few thousand of these neurons innervate the whole of the cerebral cortex, as well is the amygdala and other structures. 0
Rolls; Brain and Emotion 143 To the extent that noradrenergic neurons are involved in memory, it is likely they would have a modulatory role on cell excitability, which would influence the extent to which voltage-dependent NMDA receptors are activated, and thus the likelihood that information carried on specific afferents would be stored. 0
Rolls; Brain and Emotion 154 From research studies on animals it has been found that the lateral hypothalamus, orbitofrontal cortex, amygdala, nucleus accumbens, and ventral tegmental area are involved in the neurophysiology of reward. 11
Rolls; Brain and Emotion 155 In the neurophysiology of reward, there is a highly interconnected set of structures, whereby activity in any one will tend to stimulate neurons in the others. 1
Rolls; Brain and Emotion 157 Secondary taste cortex is in the orbitofrontal cortex. 2
Rolls; Brain and Emotion 157 Representation of taste in the secondary taste cortex is of the reward value of taste. 0
Rolls; Brain and Emotion 157 Reward value of olfactory stimuli is represented in the secondary and tertiary cortical olfactory areas in the primate orbitofrontal cortex. 0
Rolls; Brain and Emotion 157 Reward value of visual stimuli such is the sight of food is represented in the primate orbitofrontal cortex, and the learning of the representation of which visual stimuli are rewarding is built in the orbitofrontal cortex by visual-to-taste a reward learning. 0
Rolls; Brain and Emotion 168 Addictive drugs amphetamine and cocaine produce their reward by acting on the dopaminergic projections to the nucleus accumbens. 11
Rolls; Brain and Emotion 168 Dopamine appears to modulate transmission which links rewards systems and structures such as the amygdala and orbitofrontal cortex via their connections to the ventral striatum to behavioral response selection and execution systems. 0
Rolls; Brain and Emotion 168 Two catecholamines in the brain that we are concerned with are dopamine and noradrenaline (which is also known by its Greek name norepinephrine). 0
Rolls; Brain and Emotion 169 After dopamine is released into the synapse, and some of it activates the postsynaptic receptors, the remaining dopamine is removed from the synapse quickly by a number of mechanisms. 1
Rolls; Brain and Emotion 169 One mechanism for removing dopamine from the synapse is reuptake into the presynaptic terminal. 0
Rolls; Brain and Emotion 169 Another mechanism for removing dopamine from the synapse is by monoamine oxidase (MAO), which destroys the dopamine. 0
Rolls; Brain and Emotion 169 Yet another mechanism for removing dopamine from the synapse is diffusion out of the synaptic cleft. 0
Rolls; Brain and Emotion 179 General connectivity of the basal ganglia is for cortical or limbic inputs to reach the striatum, which then projects to the globus  pallidus and substantia nigra, which in turn project via the thalamus back to the cerebral cortex. Within this overall scheme, there is a set of it least partially segregated parallel processing streams. 10
Rolls; Brain and Emotion 179 Limbic and related structures such as the amygdala, orbitofrontal cortex, and hippocampus project to the ventral striatum (which includes the nucleus accumbens), which has connections through the ventral pallidum to the mediodorsal nucleus of the thalamus and  thus to the prefrontal and cingulate cortices. 0
Rolls; Brain and Emotion 191 In one hypothesis, the striatum would be particularly in involved in the selection of behavioral responses. 12
Rolls; Brain and Emotion 191 The selection of behavioral responses process may be achieved by a laterally spreading competitive interaction between striatal or pallidal neurons, which might be implemented by direct connections between nearby neurons in the striatum and globus pallidus. 0
Rolls; Brain and Emotion 191 Inhibitory interneurons within the striatum, via the interconnectivity of their dendrites, may play a part in the interaction between striatal processing streams. 0
Rolls; Brain and Emotion 191 In addition to the response selection function by competition, the basal ganglia may enable signals originating from non-motor parts of the cerebral cortex to be mapped onto motor signals to produce behavioral output. 0
Rolls; Brain and Emotion 192 Short range integration of interactions within the striatum may be produced by the short length (for example 0.5 mm) of the intrastriatal axons of striatal neurons. 1
Rolls; Brain and Emotion 192 A strong input to one part of the striatum could spread like a lateral competition signal.  Such a mechanism could contribute to behavioral response selection in the face of different competing input signals to the striatum. 0
Rolls; Brain and Emotion 192 Lateral inhibition could operate between striatal principle neurons by direct connections they receive from the cortex and could inhibit each other by their local axonal authorizations, which spread in an area as large as their dendritic trees, and which utilize GABA as their inhibitory transmitter. 0
Rolls; Brain and Emotion 193 Lateral inhibition could also operate in the pallidum and substantia nigra.  Here again there are local axon collaterals as extensive as the very large pallidal and nigral dendritic fields. 1
Rolls; Brain and Emotion 193 A selection function between processing streams in the basal ganglia, even without any convergence anatomically between the processing streams, might provide an important computational reason for the basal ganglia. 0
Rolls; Brain and Emotion 193 The direct inhibitory local connectivity between the principal neurons within the striatum and globus pallidus would seem to provide a simple, and perhaps evolutionarily old, way in which to implement competition between neurons in processing streams. This might even be a primitive design principle that characterizes the basal ganglia. 0
Rolls; Brain and Emotion 193 A system such as the basal ganglia with direct inhibitory recurrent collaterals may have evolved easily because it easier to make stable than architectures such is the cerebral cortex with recurrent excitatory connections. 0
Rolls; Brain and Emotion 193 The basal ganglia architecture may have been especially appropriate in motor systems in which instability could produce movement and coordination difficulties. 0
Rolls; Brain and Emotion 193 The hypothesis of lateral competition between neurons of the basal ganglia can be sketched simply.  The inputs from the cortex to striatum are excitatory, and competition between striatal neurons is  implemented by the use of an inhibitory transmitter (GABA), and direct connections between striatal neurons, within an area which is  approximately coextensive with the dendritic arborization. 0
Rolls; Brain and Emotion 193 Given that the lateral connections between the striatal neurons are collaterals of the output axons, the output must be inhibitory onto the pallidal and nigral neurons. 0
Rolls; Brain and Emotion 193 To transmit signals, neurons in the globus pallidus and substantia nigra must have high spontaneous firing rates and respond by reducing their firing rates. 0
Rolls; Brain and Emotion 193 A simple, and perhaps evolutionary early, aspect of basal ganglia architecture is that the striatal, pallidal, and nigral neurons implement competition (for selection) by direct inhibitory recurrent lateral connections. 0
Rolls; Brain and Emotion 194 Because of the slow conduction speed of dopaminergic neurons they are probably only suitable for more tonic, long-term adjustments of sensitivity. 1
Rolls; Brain and Emotion 194 One result of the convergence achieved by the medial pallidal/substantia nigra is that even if inputs from different cortical regions were kept segregated, there might nevertheless well be the possibility for a mutual competition between different  pallidal neurons, implemented by interneurons. 0
Rolls; Brain and Emotion 194 Given the relatively small number of neurons into which the cortical signals have been compressed, it would be feasible to have competition implemented between the relatively small population of neurons so that the competition would spread widely within these nuclei.  This would allow selection by competition between these pathways, i.e. effectively between information processing in different cortical areas. 0
Rolls; Brain and Emotion 196 Neural basis for 'habit' learning in which the basal ganglia have been implicated. 2
Rolls; Brain and Emotion 196 Storage of motor plans in the basal ganglia, which would be instantiated as a series of lookups of the appropriate motor output pattern to an evolving sequence of input information. 0
Rolls; Brain and Emotion 196 Other parts of the motor system, such is a corticocortical pathways, may mediate the control of action in a voluntary, often slow way in the early stages of learning. 0
Rolls; Brain and Emotion 196 The corticocortical pathways would set up the conditions, which because of the continuing repetition, would be learned by the basal ganglia. 0
Rolls; Brain and Emotion 196 If a strong new pattern of inputs was received by the basal ganglia, this would result in a different pattern of outputs being 'looked up' than that currently in progress. 0
Rolls; Brain and Emotion 197 Outputs of the globus pallidus and substantia nigra directed via the thalamus to motor regions such as a supplementary motor cortex and the premotor cortex potentially provide important output routes for the basal ganglia to produce actions. 1
Rolls; Brain and Emotion 197 There are also outputs of the basal ganglia to structures that may not be primarily motor, such as a dorsolateral prefrontal cortex in primates, and the inferior temporal visual cortex. 0
Rolls; Brain and Emotion 197 The hypothesis of basal ganglia function incorporates associative learning of cognitive inputs onto neurons, at both the cortico-striatal stages, and the striato-palladal and nigral stages. 0
Rolls; Brain and Emotion 197 Consistent with this hypothesis of basal ganglia action it has been possible to demonstrate long-term potentiation (LTP) in at least some parts of the basal ganglia. 0
Rolls; Brain and Emotion 197 Researchers have demonstrated LTP of limbic inputs to the nucleus accumbens, and were able to show that such LTP is facilitated by dopamine. 0
Rolls; Brain and Emotion 198 The ventral striatum would still be an area allowing convergence of signals from the amygdala, orbitofrontal cortex, and hippocampus. 1
Rolls; Brain and Emotion 297 A sparse distributed representation is a distributed representation in which a small proportion of the neurons is active at any one time. 99
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