Biomedical subjects

Jari K Hietanen

Publications and source records attributed to Jari K Hietanen.

12 recordsLinked to original sources

PubMed2006

Automatic attention orienting by social and symbolic cues activates different neural networks: an fMRI study.

Visual attention can be automatically re-oriented by another person's non-predictive gaze as well as by symbolic arrow cues. We investigated whether the shifts of attention triggered by biologically relevant gaze cues and biologically non-relevant arrow cues rely on the same neural systems by comparing the effects of gaze-cued and arrow-cued orienting on blood oxygenation level-dependent (BOLD) signal in humans. Participants detected laterally presented reaction signals preceded by centrally presented non-predictive gaze and arrow cues. Directional gaze cues and arrow cues were presented in separate blocks. Furthermore, two separate control blocks were run in which non-directional cues (straight gaze or segment of a line) were used. The BOLD signals during the control blocks were subtracted from those during the respective blocks with directional cues. Behavioral data showed that, for both cue types, reaction times were shorter on congruent than incongruent trials. Imaging data revealed three foci of activation for gaze-cued orienting: in the left inferior occipital gyrus and right medial and inferior occipital gyri. For arrow-cued orienting, a much more extensive network was activated. There were large postcentral activations bilaterally including areas in the medial/inferior occipital gyri and medial temporal gyri and in the left intraparietal area. Interestingly, arrow cuing also activated the right frontal eye field and supplementary eye field. The results suggest that attention orienting by gaze cues and attention orienting by arrow cues are not supported by the same cortical network and that attention orienting by symbolic arrow cues relies on mechanisms associated with voluntary shifts of attention.

Adult↗

PubMed2006

Gaze distractors influence saccadic curvature: evidence for the role of the oculomotor system in gaze-cued orienting.

We examined the role of the oculomotor system in gaze-triggered orienting of attention by measuring whether perceiving of task-irrelevant gaze distractors and peripheral spatial distractors influence saccadic curvature similarly. Participants performed reflexive, vertical saccades to designated target areas while their eye movements were recorded. Schematic faces with averted gaze or peripheral boxes were presented before or simultaneously (-100 ms/0 ms SOAs) with the imperative signal. Gaze distractors caused the saccades to curve away from the distractor direction at both SOAs and peripheral distractors only at the 0-ms SOA. The results imply that gaze-cued shifts of visual attention involve both cortical attention orienting systems and subcortical oculomotor systems.

Adult↗

PubMed2006

What is a nice smile like that doing in a place like this? Automatic affective responses to environments influence the recognition of facial expressions.

An affective priming paradigm with pictures of environmental scenes and facial expressions as primes and targets, respectively, was employed in order to investigate the role of natural (e.g., vegetation) and built elements (e.g., buildings) in eliciting rapid affective responses. In Experiment 1, images of environmental scenes were digitally manipulated to make continua of priming pictures with a gradual increase of natural elements (and a decrease of built elements). The primes were followed by presentations of facial expressions of happiness and disgust as to-be-recognized target stimuli. The recognition times of happy faces decreased and the recognition times of disgusted faces increased as the quantity of natural/built material present in the primes increased/decreased. The physical changes also influenced the evaluated restorativeness and affective valence of the primes. In Experiment 2, the primes used in Experiment 1 were manipulated in such a way that they were void of any recognizable natural or built elements but contained either similar colours or similar shapes as primes in Experiment 1. This time the results showed no effect of priming. These results were interpreted to give support for a view that the priming effect by environmental pictures is due to the primes representing environmental scenes and not due to the presence of certain low-level colour or shape information in the primes. In all, the present results provide evidence that perception of environmental scenes elicits automatic affective responses and influences recognition of facial expressions.

Adolescent↗

PubMed2006

Skin conductance responses to another person's gaze in children with autism.

The effects of another person's gaze on physiological arousal were investigated by measuring skin conductance responses (SCR). Twelve able children with autism and 12 control children were shown face stimuli with straight gaze (eye contact) or averted gaze on a computer monitor. In children with autism, the responses to straight gaze were stronger than responses to averted gaze, whereas there was no difference in the responses to these gaze conditions in normally developing children. Thus, these results showed that eye gaze elicited differential pattern of SCR in normally developing children and in children with autism. It is possible that the enhanced arousal to eye contact may contribute to the abnormal gaze behaviour frequently reported in the context of autism.

Autistic Disorder↗

PubMed2006

Face and gaze processing in normally developing children: a magnetoencephalographic study.

Magnetoencephalography (MEG) was used to study the neural mechanisms underlying face and gaze processing in ten normally developing boys aged between 8 and 11 years and 12 adult males. The participants performed two tasks in which they had to decide whether images presented sequentially in pairs, depicted the same person or the same motorbike. In the first task, the participants saw pictures of faces in which the eyes were either open or shut and pictures of motorbikes. In the second task, participants saw pairs of faces with gaze averted to the left or right. In children there was no evidence of the face sensitive, low amplitude short latency (30-60 ms) activity seen previously in adults. A strong, midline posterior response at approximately 100 ms was observed in children, which was earlier and somewhat stronger to faces than to motorbikes; in adults the signal at this latency was weak. A clear face sensitive response was seen in adults at 135 ms, predominantly over the right inferior occipito-temporal regions. Although activity was observed in the children at the same latency, it was less prominent, not lateralized and was evoked similarly by faces and motorbikes. Averted gaze conditions evoked strong right-lateralized activity at approximately 245 ms in children only. These findings indicate that even in middle childhood the neural mechanisms underlying face processing are less specialized than in adults, with greater early activation of posterior occipital cortices and less specific activation of ventral occipito-temporal cortex.

Adult↗

PubMed2006

Face- and gaze-sensitive neural responses in children with autism: a magnetoencephalographic study.

Face and gaze processing were studied using magnetoencephalography in 10 children with autism and 10 normally developing children, aged between 7 and 12 years. The children performed two tasks in which they had to discriminate whether images of faces presented sequentially in pairs were identical. The images showed four different categories of gaze: direct gaze, eyes averted (left or right) and closed eyes but there was no instruction to focus on the direction of gaze. Images of motorbikes were used as control stimuli. Faces evoked strong activity over posterior brain regions at about 100 ms in both groups of children. A response at 140 ms to faces observed over extrastriate cortices, thought to be homologous to the N170 in adults, was weak and bilateral in both groups and somewhat weaker (approaching significance) in the children with autism than in the control children. The response to motorbikes differed between the groups at 100 and 140 ms. Averted eyes evoked a strong right lateralized component at 240 ms in the normally developing children that was weak in the clinical group. By contrast, direct gaze evoked a left lateralized component at 240 ms only in children with autism. The findings suggest that face and gaze processing in children with autism follows a trajectory somewhat similar to that seen in normal development but with subtle differences. There is also a possibility that other categories of object may be processed in an unusual way. The inter-relationships between these findings remain to be elucidated.

Autistic Disorder↗

PubMed2004

Depression biases the recognition of emotionally neutral faces.

Functional abnormalities in emotion-related brain systems have been implicated in depression, and depressed patients may therefore attribute emotional valence to stimuli that are normally interpreted as emotionally neutral. The present study examined this hypothesis by comparing recognition of different facial expressions in patients with moderate to severe depression. Eighteen depressed patients and 18 matched healthy controls made a forced-choice response to briefly presented neutral, happy, and sad faces. Recognition accuracy and response time were measured. Twelve patients were retested after showing signs of symptom remission. Depressed patients and controls were equally accurate at recognizing happy and sad faces. Controls also recognized neutral faces as accurately as happy and sad faces, but depressed patients recognized neutral faces less accurately than either happy or sad faces. Depressed patients were also particularly slow to recognize neutral faces. The impairment in processing of neutral faces was still evident after symptom remission. Error analyses showed that depressed patients attributed not only sadness, but also happiness (in remission), to neutral faces. These results suggest that, unlike healthy subjects, depression-prone individuals do not seem to perceive neutral faces as unambiguous signals of emotional neutrality.

Adult↗

PubMed2004

Attention orienting by another's gaze direction in children with autism.

BACKGROUND: The aim of this study was to investigate attention orienting triggered by another's gaze direction in autism. METHOD: Twelve high-functioning children with autism and gender- and age-matched normal control children were studied using two tasks. In the first task, children were asked to detect laterally presented target stimuli preceded by centrally presented facial cue stimuli in which gaze was either straight ahead or averted. The direction of the cue was either congruent, neutral, or incongruent with respect to the laterality of the target stimulus. In the second task, children were asked to discriminate the direction of eye gaze. RESULTS: The results showed that another person's static gaze direction triggered an automatic shift of visual attention, both in children with autism and in normally developing children. The children in both groups were also able to overtly discriminate the direction of the gaze. CONCLUSION: These results seem to suggest that, in children with autism, the visual system processes information about another person's gaze direction and sends this information to those areas that subserve reflexive attention orienting. However, future studies are needed to investigate whether the processing of eyes and gaze direction relies on similar neural mechanisms in children with autism and in normally developing children.

Attention↗

PubMed2003

Positive facial expressions are recognized faster than negative facial expressions, but why?

Three experiments examined the recognition speed advantage for happy faces. The results replicated earlier findings by showing that positive (happy) facial expressions were recognized faster than negative (disgusted or sad) facial expressions (Experiments 1 and 2). In addition, the results showed that this effect was evident even when low-level physical differences between positive and negative faces were controlled by using schematic faces (Experiment 2), and that the effect was not attributable to an artifact arising from facilitated recognition of a single feature in the happy faces (up-turned mouth line, Experiment 3). Together, these results suggest that the happy face advantage may reflect a higher-level asymmetry in the recognition and categorization of emotionally positive and negative signals.

Adolescent↗

PubMed2003

Does facial expression affect attention orienting by gaze direction cues?

In 6 experiments, the authors investigated whether attention orienting by gaze direction is modulated by the emotional expression (neutral, happy, angry, or fearful) on the face. The results showed a clear spatial cuing effect by gaze direction but no effect by facial expression. In addition, it was shown that the cuing effect was stronger with schematic faces than with real faces, that gaze cuing could be achieved at very short stimulus onset asynchronies (14 ms), and that there was no evidence for a difference in the strength of cuing triggered by static gaze cues and by cues involving apparent motion of the pupils. In sum, the results suggest that in normal, healthy adults, eye direction processing for attention shifts is independent of facial expression analysis.

Adult↗

PubMed2003

Affect and face perception: odors modulate the recognition advantage of happy faces.

Previous choice reaction time studies have provided consistent evidence for faster recognition of positive (e.g., happy) than negative (e.g., disgusted) facial expressions. A predominance of positive emotions in normal contexts may partly explain this effect. The present study used pleasant and unpleasant odors to test whether emotional context affects the happy face advantage. Results from 2 experiments indicated that happiness was recognized faster than disgust in a pleasant context, but this advantage disappeared in an unpleasant context because of the slow recognition of happy faces. Odors may modulate the functioning of those emotion-related brain structures that participate in the formation of the perceptual representations of the facial expressions and in the generation of the conceptual knowledge associated with the signaled emotion.

Adult↗

PubMed2002

Social attention orienting integrates visual information from head and body orientation.

Subjects were asked to detect visual, laterally presented reaction signals preceded by head-body cue stimuli in a spatial cueing task. A head rotated towards the reaction signal combined with a front view of a body resulted in shorter reaction times in comparison to the front view of a head and body. In contrast, a cue showing the head and body rotated towards the reaction signal did not result in such a facilitation in reaction times. The results suggest that the brain mechanisms involved in social attention orienting integrate ventrally processed visual information from the head and body orientation. A cue signaling that the other person, in his or her frame of reference, has an averted attention direction shifts the observer's own attention in the same direction.

Adult↗