Impulse activity of neurons of the visual and somatosensory regions of the cerebral cortex at different stages of goal-directed behavior

Impulse activity of neurones of the visual and somatosensory cortical areas was studied in free moving cats during performance of conditioned instrumental food-procuring reactions to the presentation of light or sound. It was established that the units of these cortical areas may participate in both all or individual stages of complex instrumental behaviour. The visual cortex neurones are more extensively involved in the formation of successive stages of the goal-directed behavioral act. Significant differences were revealed in the unit responses of the visual and somatosensory cortical areas at the moment of the switching on of the conditioned signal, at the period of "reinforcement anticipation", at the moment of appearance of milk, the reinforcing agent, and during reinforcement, when the milk was lapped by the animal.     

The rules of formation of the olfactory representations found in the orbitofrontal cortex olfactory areas in primates.

Approximately 35% of neurons in the orbitofrontal cortex taste and olfactory areas with olfactory responses provide a representation of odour that depends on the taste with which the odour has been associated previously. This representation is produced by a slowly acting learning mechanism that learns associations between odour and taste. Other neurons in the orbitofrontal cortex respond to both the odour and to the mouth feel of fat. The representation of odour thus moves for at least some neurons in the orbitofrontal cortex beyond the domain of physico-chemical properties of the odours to a domain where the ingestion-related significance of the odour determines the representation provided. Olfactory neurons in the primate orbitofrontal cortex decrease their responses to a food eaten to satiety, but remain responsive to other foods, thus contributing to a mechanism for olfactory sensory-specific satiety. It has been shown in neuroimaging studies that the human orbitofrontal cortex provides a representation of the pleasantness of odour, in that the activation produced by the odour of a food eaten to satiety decreases relative to another food-related odour not eaten in the meal. In the same general area there is a representation of the pleasantness of the smell, taste and texture of a whole food, in that activation in this area decreases to a food eaten to satiety, but not to a food that has not been eaten in the meal.     

Functions of the orbitofrontal and pregenual cingulate cortex in taste, olfaction, appetite and emotion

Complementary neurophysiological recordings in macaques and functional neuroimaging in humans show that the primary taste cortex in the rostral insula and adjoining frontal operculum provides separate and combined representations of the taste, temperature, and texture (including viscosity and fat texture) of food in the mouth independently of hunger and thus of reward value and pleasantness. One synapse on, in the orbitofrontal cortex, these sensory inputs are for some neurons combined by learning with olfactory and visual inputs. Different neurons respond to different combinations, providing a rich representation of the sensory properties of food. The representation of taste and other food-related stimuli in the orbitofrontal cortex of macaques is found from its lateral border throughout area 13 to within 7 mm of the midline, and in humans the representation of food-related and other pleasant stimuli is found particularly in the medial orbitofrontal cortex. In the orbitofrontal cortex, feeding to satiety with one food decreases the responses of these neurons to that food, but not to other foods, showing that sensory-specific satiety is computed in the primate (including human) orbitofrontal cortex. Consistently, activation of parts of the human orbitofrontal cortex correlates with subjective ratings of the pleasantness of the taste and smell of food. Cognitive factors, such as a word label presented with an odour, influence the pleasantness of the odour, and the activation produced by the odour in the orbitofrontal cortex. Food intake is thus controlled by building a multimodal representation of the sensory properties of food in the orbitofrontal cortex, and gating this representation by satiety signals to produce a representation of the pleasantness or reward value of food which drives food intake. A neuronal representation of taste is also found in the pregenual cingulate cortex, which receives inputs from the orbitofrontal cortex, and in humans many pleasant stimuli activate the pregenual cingulate cortex, pointing towards this as an important area in motivation and emotion.     

Brain mechanisms underlying flavour and appetite

Complementary neurophysiological recordings in macaques and functional neuroimaging in humans show that the primary taste cortex in the rostral insula and adjoining frontal operculum provides separate and combined representations of the taste, temperature and texture (including viscosity and fat texture) of food in the mouth independently of hunger and thus of reward value and pleasantness. One synapse on, in the orbitofrontal cortex, these sensory inputs are for some neurons combined by learning with olfactory and visual inputs. Different neurons respond to different combinations, providing a rich representation of the sensory properties of food. In the orbitofrontal cortex, feeding to satiety with one food decreases the responses of these neurons to that food, but not to other foods, showing that sensory-specific satiety is computed in the primate (including human) orbitofrontal cortex. Consistently, activation of parts of the human orbitofrontal cortex correlates with subjective ratings of the pleasantness of the taste and smell of food. Cognitive factors, such as a word label presented with an odour, influence the pleasantness of the odour and the activation produced by the odour in the orbitofrontal cortex. These findings provide a basis for understanding how what is in the mouth is represented by independent information channels in the brain; how the information from these channels is combined; and how and where the reward and subjective affective value of food is represented and is influenced by satiety signals. Activation of these representations in the orbitofrontal cortex may provide the goal for eating, and understanding them helps to provide a basis for understanding appetite and its disorders.     

The interaction of mediators with protein synthesis processes in the visual cortex neurons in the goal-directed behavior of cats]

The chemical sensitivity was studied of the neurones of cats visual cortex at successive stages of food-procuring instrumental behaviour, formed in conditions of intraventricular administration of the blocker of protein synthesis the cyclohexamide. Animals with cyclohexamide had a low chemical sensitivity of the cortical neurones to microionophoretically applied solutions of acetylcholine and noradrenaline. In comparison with the intact animals, in animals with cyclohexamide the number of neurones reacting with change of the impulse activity at the stages of instrumental behaviour as well as the number of areactive cells, did not depend on the nature of the applied neurotransmitter.     

Neuronal specialization of the motor cortex in normal rabbits and following destruction of the visual cortex

The activity of neurones of the anterolateral part of the motor cortex in food-acquisition behaviour was compared in two control rabbits and in three rabbits after the operation of bilateral ablation of the striatal cortex. In two of three operated rabbits the pattern of behavioural specialization lost considerably the specificity peculiar to the motor cortex (predominance of G-neurones activated in grasping of food), approaching (but not becoming identical) the pattern of specialization of the visual cortex neurones: the number of G-neurones decreased in a half, and the number of L-neurones (activated in connection with the acts of instrumental food-acquisition behaviour which animals were trained to in the experimental cage) was doubled. Changes of the activity were significantly less expressed in the third operated rabbit. The number of the neurones activated in food-acquisition behaviour in operated rabbits in comparison with the control ones was reduced in the upper layers of the cortex and increased in the lower layers. The resemblance is discussed of the basic processes of animals learning and behaviour recovery.     

The effect of the acute administration of ethanol on the realization of behavior and its neuronal support

In experiments on rabbits trained to instrumental food procuring behaviour it was cleared up, which changes of activity of neurones of the limbic cortical area corresponded to disturbances of this behaviour (increase in time of realization and in the number of errors) caused by intraperitoneal injection of 12% ethanol solution in a dose of 1 g/kg. In comparison with control (administration of isotonic solution), the number of active cells singled out in the microelectrode track was reduced by 1/3; the pattern of behavioural specialization of neurones involved in provision of the disturbed behaviour was changed. The content of neurones of the most recent systems formed during animals learning instrumental behaviour, decreased from 27 to 11%, and of neurones providing for realization of systems formed at previous stages of individual development increased from 18 to 36%.     

Response activity of different areas of the associative region of the cerebral cortex in the cat

In cats we have simultaneously (monopolarly) recorded the responses in different parts of the associative cortex (ac) (motor cortex, proreal, orbital, anterior marginal, and mid-part of the suprasylvian gyri) appearing for different peripheral stimulations (stimulation of the skin of the forelimbs, a light flash and a sound click). In all the regions of the ac associative responses (ar) almost identical in configuration appeared to all the peripheral stimulations. The ar of the orbitofrontal and the motor cortex differed from the ar of the suprasylvian gyrus in the shorter latent period and greater stability. In each part of the ac we found the same focus of maximum activity for all the peripheral stimulations. For paired stimulations of the same and different modalities the greatest stability in relation to the blocking influence due to the conditioning stimulation characterized the ar which appeared in response to skin stimulation in the orbitofrontal cortex and the ar which appeared in the suprasylvian gyrus on exposure to a light flash. It is assumed that in the orbitofrontal cortex an efferent discharge is formed in response to pulses of different sensory modality whereas in the suprasylvian gyrus there is only sensory integration. Some aspects of afferent convergence are discussed.Institute of Physiology, Academy of Sciences of the Georgian SSR, Tbilisi. Translated from Neirofiziologiya, Vol. 2, No. 2, pp. 126–139, March–April, 1970.     

The neuronal activity of the caudate nucleus in monkeys during the realization of delayed behavior]

A greater part (64%) of recorded neurones of the caudate nucleus head changed its activity at various stages of fulfillment by the monkey of the task of delayed spatial choice. Most of them (46.5% of all studied) reacted at key depressing and/or taking food from the feeder. During signal presentation and with delay the frequency of impulse activity changed respectively in 17% and 14% of the studied neurones. Besides, 2 neurones had spatially-selective activity in the instructive period of the program. It can be suggested that caudate neurones participate in realization of the delayed behaviour not only during motor response fulfillment but in the instructive period as well--at the stage of perception and processing of the visual information and its storing in short-term memory.     

The Woman in the Surgeon's Body: Understanding Difference

Praxis is not simply about learning cultural rules by rote, it is about coming to an understanding of social distinctions through your body.
Much of clinical and practical knowledge [in medicine] is embodied knowledge-knowledge sensed through and with the body. This includes senses of sight, sound, touch, smell.     

Neural coding of basic reward terms of animal learning theory, game theory, microeconomics and behavioural ecology

Neurons in a small number of brain structures detect rewards and reward-predicting stimuli and are active during the expectation of predictable food and liquid rewards. These neurons code the reward information according to basic terms of various behavioural theories that seek to explain reward-directed learning, approach behaviour and decision-making. The involved brain structures include groups of dopamine neurons, the striatum including the nucleus accumbens, the orbitofrontal cortex and the amygdala. The reward information is fed to brain structures involved in decision-making and organisation of behaviour, such as the dorsolateral prefrontal cortex and possibly the parietal cortex. The neural coding of basic reward terms derived from formal theories puts the neurophysiological investigation of reward mechanisms on firm conceptual grounds and provides neural correlates for the function of rewards in learning, approach behaviour and decision-making.     

Plastic changes of the network properties of neurons during learning in the cat

Functional connections between neurones of various types in microareas and between microareas of the motor cortex in cats have been studied during elaboration of an electro-defensive reflex to sound. A difference has been shown between neighbouring neurones in formation of their contacts with nearby neurones located within an area of 500 mc. Neurones generating spikes of high amplitude had more active "outputs" to neurones situated at different distances, while neurones generating spikes of low amplitude had more active "inputs" to them. On the other hand, as a result of conditioning "inputs" to distant neurones underwent more significant changes in the first type of neurones, and in the second type--the "outputs" changed more markedly.     

Neuronal activity of the sensorimotor area of the rabbit cerebral cortex in zoosocial behavior

The present study was aimed to investigate the neural activity during competitor relationships in the social interactions and operant feeding behaviour. In experiments on three pairs of rabbits the activity of 32 sensory-motor cortex neurones were analyzed. 21 neurones were found specialized relatively to different acts of social behaviour. They did not participate in provision for "individual" types of behaviour.     

Separable substrates for anticipatory and consummatory food chemosensation

Perception of the smell of a food precedes its ingestion and perception of its flavor. The neurobiological underpinnings of this association are not well understood. Of central interest is whether the same neural circuits code for anticipatory and consummatory phases. Here, we show that the amygdala and mediodorsal thalamus respond preferentially to food odors that predict immediate arrival of their associated drink (FO+) compared to food odors that predict delivery of a tasteless solution (FO-) and compared to the receipt of the drink. In contrast, the left insula/operculum responds preferentially to the drink, whereas the right insula/operculum and left orbitofrontal cortex respond to FO+ and drink. These findings indicate separable and overlapping representation of anticipatory and consummatory chemosensation. Moreover, since ratings of perceived pleasantness of FO+, FO-, and drink were similar, the response in the amygdala and thalamus cannot reflect acquired affective value but rather predictive meaning or biological relevance.     

The human orbitofrontal cortex: linking reward to hedonic experience

Hedonic experience is arguably at the heart of what makes us human. In recent neuroimaging studies of the cortical networks that mediate hedonic experience in the human brain, the orbitofrontal cortex has emerged as the strongest candidate for linking food and other types of reward to hedonic experience. The orbitofrontal cortex is among the least understood regions of the human brain, but has been proposed to be involved in sensory integration, in representing the affective value of reinforcers, and in decision making and expectation. Here, the functional neuroanatomy of the human orbitofrontal cortex is described and a new integrated model of its functions proposed, including a possible role in the mediation of hedonic experience.     

Differences in the responses of identified neurons to chemical stimuli in satiated and hungry edible snails

Reactions of command neurones for avoidance behaviour to food were investigated in hungry and satiated snails in "CNS-chemoreceptor" preparations, in which hemolymph was washed out by saline. Neuronal responses in hungry animal preparations differed significantly from responses in satiated animals preparations. Perfusion of hungry animal preparations with hemolymph of satiated animals changed significantly the responses of command neurones for avoidance behaviour. These responses resembled the reactions of the same neurones to food after aversive conditioning to food of hungry snails. The role of humoral factor in learning is discussed.     

食物奖赏和渴求行为相关的大鼠左侧眶额叶皮质Delta频段脑电活动(英文）

眶额叶皮质与中脑边缘多巴胺奖赏系统有着复杂的相互纤维联系。先前的研究探讨了药物成瘾过程中眶额叶皮质的脑电活动。在本实验中,将探讨食物奖赏和渴求过程中该皮质的脑电活动。实验采用了两个环境:对照环境和食物刺激相关的环境。首先,训练大鼠在食物刺激相关的环境中吃巧克力花生豆,而后在该环境中设置两种不同的刺激方式:能看到和闻到但不能吃到(渴求实验),或者仍旧可以吃到巧克力花生豆(奖赏实验);同时进行左侧眶额叶皮质的脑电记录。结果发现,在食物刺激相关的环境中大鼠 Delta 频段(2-4 Hz)的脑电活动与食物刺激显著相关,此外,与在对照环境中相比,其相对功率在食物渴求时下降而在食物奖赏时升高。本实验表明,食物相关的奖励可以改变大鼠眶额叶皮质的脑电活动,而且,Delta 频段的脑电活动能够作为监测该奖励的一个指标。     

The dynamics of the activating and inhibitory types of cortical neuron synchronization during the realization of a defensive reflex and internal inhibition

In the visual and sensorimotor areas of the neocortex and in the hippocampus of alert nonimmobilized rabbits, in response to combinations of light flashes with electrocutaneous limb stimulation an increase was observed of synchronization in the activity of the near-by neurones by activation by inhibitory type (coincidence of the presence and absence of impulse activity). In response to flashes against the light background--conditioned inhibitor--in the visual cortex synchronization of neurones increased by inhibitory type, and in the sensorimotor cortex and hippocampus changes of synchronization appeared, similar to the action of pain reinforcement but considerably weaker. The increase of synchronization by the activation type took place mainly in the neurones pairs with unidirected increase of impulses frequency and by the inhibitory one--with its decrease. Along with this, in a considerable part of neurones pairs both changes of synchronization appeared at the impulses frequency changes of different direction.     

Neuronal activity in self-stimulation zones of the hypothalamus in motivational and emotional states induced by electrical and natural stimuli

Study of neuronal activity in hypothalamus areas of self-stimulation in rats showed two types of neurones. Some of them had an increased frequency at food and water deprivation and they had maximum activation at current stimulation, eliciting motivational behaviour. Others had maximum activation at current level, eliciting self-stimulation effects, some of these neurones had positive activating relation to satisfaction of food requirements. The obtained data are considered as morphofunctional substrate of motivational and emotional states.     

Adaptability of the receptive fields of neurons of the posterior temporal cortex and their sensitivity to parameters of photic stimulation in the cat

Study of receptive fields (RFs) of neurones in the postero-temporal cortex (field 21) of alert cat at three levels of visual adaptation: light photopic, light mesopic and practically dark or extremely low scotopic adaptations--revealed invariance of the most part of the studied RFs to the level of visual adaptation. Reorganization of RFs, connected with change of background luminosity were observed only in 12% of visually activated neurones. Significant reduction of responses to optic stimulation is shown at increase of the level of luminosity in 75% of neurones, revealing adaptive reorganizations. It is suggested that these reorganizations may take place in analogy with neurones of the field 17 on account of different involvement of intracortical inhibitory mechanisms (and, probably, not only in the postero-temporal cortex, but also in structures which precede it in visual hierarchy). Study of neurones sensitivity in the field 21 to parameters of optic stimulation revealed their considerable invariance to the length and orientation of the optic stimulus moving through the RF (60% of cases). Testing of RF by a rhombic optic stimulus did not change neuronal reactions, the form and dimensions of RF did not significantly change.